• Korean Journal of Agricultural Science
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• v.4 no.2
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• pp.344-390
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• 1977

The purpose of this paper was to schedule optimum cutting strategy which could maximize the total yield under certain restrictions on periodic timber removals and harvest areas from an industrial forest, based on a linear programming technique. Sensitivity of the regulation model to variations in restrictions has also been analyzed to get information on the changes of total yield in the planning period. The regulation procedure has been made on the experimental forest of the Agricultural College of Seoul National University. The forest is composed of 219 cutting units, and characterized by younger age group which is very common in Korea. The planning period is devided into 10 cutting periods of five years each, and cutting is permissible only on the stands of age groups 5-9. It is also assumed in the study that the subsequent forests are established immediately after cutting existing forests, non-stocked forest lands are planted in first cutting period, and established forests are fully stocked until next harvest. All feasible cutting regimes have been defined to each unit depending on their age groups. Total yield (Vi, k) of each regime expected in the planning period has been projected using stand yield tables and forest inventory data, and the regime which gives highest Vi, k has been selected as a optimum cutting regime. After calculating periodic yields and cutting areas, and total yield from the optimum regimes selected without any restrictions, the upper and lower limits of periodic yields(Vj-max, Vj-min) and those of periodic cutting areas (Aj-max, Aj-min) have been decided. The optimum regimes under such restrictions have been selected by linear programming. The results of the study may be summarized as follows:- 1. The fluctuations of periodic harvest yields and areas under cutting regimes selected without restrictions were very great, because of irregular composition of age classes and growing stocks of existing stands. About 68.8 percent of total yield is expected in period 10, while none of yield in periods 6 and 7. 2. After inspection of the above solution, restricted optimum cutting regimes were obtained under the restrictions of Amin=150 ha, Amax=400ha, $Vmin=5,000m^3$ and $Vmax=50,000m^3$, using LP regulation model. As a result, about $50,000m^3$ of stable harvest yield per period and a relatively balanced age group distribution is expected from period 5. In this case, the loss in total yield was about 29 percent of that of unrestricted regimes. 3. Thinning schedule could be easily treated by the model presented in the study, and the thinnings made it possible to select optimum regimes which might be effective for smoothing the wood flows, not to speak of increasing total yield in the planning period. 4. It was known that the stronger the restrictions becomes in the optimum solution the earlier the period comes in which balanced harvest yields and age group distribution can be formed. There was also a tendency in this particular case that the periodic yields were strongly affected by constraints, and the fluctuations of harvest areas depended upon the amount of periodic yields. 5. Because the total yield was decreased at the increasing rate with imposing stronger restrictions, the Joss would be very great where strict sustained yield and normal age group distribution are required in the earlier periods. 6. Total yield under the same restrictions in a period was increased by lowering the felling age and extending the range of cutting age groups. Therefore, it seemed to be advantageous for producing maximum timber yield to adopt wider range of cutting age groups with the lower limit at which the smallest utilization size of timber could be produced. 7. The LP regulation model presented in the study seemed to be useful in the Korean situation from the following point of view: (1) The model can provide forest managers with the solution of where, when, and how much to cut in order to best fulfill the owners objective. (2) Planning is visualized as a continuous process where new strateges are automatically evolved as changes in the forest environment are recognized. (3) The cost (measured as decrease in total yield) of imposing restrictions can be easily evaluated. (4) Thinning schedule can be treated without difficulty. (5) The model can be applied to irregular forests. (6) Traditional regulation methods can be rainforced by the model.

• Journal of Korean Society of Forest Science
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• v.29 no.1
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• pp.54-101
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• 1976

This study was conducted on the major factors affecting soil erosion and surface run-off. In order to investigate the processes and mechanisms of soil erosion on denuded forest-land in Korea, and to systematize the magnitudes of influences and interactions between individual factors, the five major factors adopted in these experiments are soil textures (coarse sand and clay loam), slope steepness ($10^{\circ}$, $20^{\circ}$, $30^{\circ}$ and $40^{\circ}$), rainfall intensities (50, 75 and 100mm/hr), slope mulching methods (bare, coarse straw-mat mulching, grass mulching and anti-erosion liquid mulching) and vegetation densities (sparse, moderate and dense). The processes and mechanisms of soil erosion, and the effects of mulchings on soil erosion as well as surface run-off rates were studied algebraically with four parts of laboratory experiments under the simulated rainfall and another part of field experiment under the natural rainfall. The results in this study are summarized as follows: 1. Experiment factors and surface run-off rates The surface run-off rates under the natural rainfall were resulted about 24.7~28.7% from the bare slopes, about 14.0~16.4% from the straw-mat mulched slopes, about 7.9~9.1% from the liquid mulched slopes, and about 5.6~7.2% from the grass mulched slopes respectively. The surface run-off rates under the simulated rainfall differed greatly according to the rainfall intensity and the mulching method. 2. Magnitudes of influences and interactions of the individual factor on the surface run-off rates. The experimental analyses on the major factors(soils, slopes, rainfalls, mulchings and vegetations) affecting the rates of surface run-off, show that the mean differences of surface run-off rate are significant at 5% level between the soil texture factors, among the slope steepness factors, among the rainfall intensity factors, among the mulching method factors, and among the vegetation density factors respectively. The interactions among the individual factor have a great influence(significant at 1% level) upon the rate of surface run-off, except for the interactions of the factors between soils and slopes; between slopes and vegetations; among soils, slopes and rainfalls; and among soils, slopes and mulchings respectively. On the bare slopes under the simulated rainfall, the magnitude of influences of three factors(soils, slopes and rainfalls) affecting the rate of surface run-off is in the order of the factor of rainfalls, soils and slopes. The magnitude of influences of three factors (soils, rainfalls and mulchings) affecting the rate of surface run-off, on the mulched slopes under the simulated rainfall is in the order of the factor of mulchings, rainfalls and soils and that of influences of the factor of soils, slopes and mulchings is in the order of the factor of mulchings, soils and slopes. On the vegetation growing slopes under the simulated rainfall, the magnitude of influences of three factors (soils, slopes and vegetations) affecting the rate of surface run-off is in the order of the factor of vegetations, soils and slopes. In the same condition of treatments on the field experiment under the natural rainfall, the order of magnitude of influences affecting the rate of surface run-off is the factor of mulchings, soils and slopes. 3. Experiment factors and soil losses The soil losses of the experiment plots differed according to the factors of soil texture, slope steepness, rainfall intensity and mulching method. The soil losses from the coarse soil were increased about 1.1~1.3 times as compared with that of fine soil under the natural rainfall, while the soil losses from the fine soil were increased about 1.2~1.3 times compared with that of coarse soil under the simulated rainfall. The equation of $E=aS^b$ (a, b are constant) between the slope steepness (log S) and soil losses (log E) under the simulated rainfall were developed. The equation of $E=aI^b$ (a, b are constant) between the rainfall intensity (log I) and soil losses (log E) were developed, and b values have a decreasing tendency according to the increase of the slope steepness and rainfall intensity. The soil losses under the natural rainfall were appeared about 38~41% from the coarse straw-mat mulched slopes, about 20~22% from the liquid mulched slopes, about 14~15% from the grass mulched slopes as compared with that of the bare slopes respectively. The soil loss from the vegetation plots showed about 7.1~16.4 times from the sparse plot, about 10.0~17.9 times from the moderate plot and about 11.1~28.1 times from the dense plot as compared with that of the bare slopes. 4. Magnitudes of influences and interactions of the individual factor on the soil erosion. The experimental analyses on the major factors(soils, slopes, rainfalls, mulchings and vegetations) affecting the soil erosion, show that the mean differences of soil losses are highly significant between the soil texture factors, among the slope steepness factors, among the rainfall intensity factors, among the mulching method factors and among the vegetation density factors respectively. The interactions among the individual factor have mostly great influences upon the soil erosion. The magnitude of influences of three factors (soils, slopes and rainfalls) affecting the soil erosion on the bare slopes under the simulated rainfall is in order of the factor of rainfalls, soils and slopes. On the mulched slopes under the simulated rainfall, the magnitude order of influences of three factors(soils, rainfalls and mulchings) affecting the soil erosion is the factor of mulchings, rainfalls and soils, and the order of influences of factor of soils, slopes and mulchings is the factor of mulchings, soils and slopes. On the vegetation growing slopes under the simulated rainfall, the magnitude of influences of three factors (soils, slopes and vegetations) affecting the soil erosion is in the order of the factor of slopes. vegetations and soils. In the same condition of treatments on the field experiment under the natural rainfall, the order of magnitude of influences of three factors (soils, slopes and mulchings) affecting the soil erosion is the factor of mulchings, of slopes and of soils.

• Journal of Information Management
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• v.6 no.5
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• pp.131-134
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• 1973

본고(本稿)시리이즈의 제1보(第一報)에서 우리는 물리(物理), 사회과학(社會科學) 및 공학분야(工學分野)의 12,442명(名)의 과학자(科學者)와 기술자(技術者)에 대한 정보교환활동(情報交換活動)의 78례(例)에 있어서 일반과정(一般過程)과 몇 가지 결과(結果)를 기술(記述)한 바 있다. 4년반(年半) 이상(以上)의 기간(其間)($1966{\sim}1971$)에서 수행(遂行)된 이 연구(硏究)는 현재(現在)의 과학지식(科學知識)의 집성체(集成體)로 과학자(科學者)들이 연구(硏究)를 시작(始作)한 때부터 기록상(記錄上)으로 연구결과(硏究結果)가 취합(聚合)될 때까지 각종(各種) 정형(定形), 비정형(非定形) 매체(媒體)를 통한 유통정보(流通情報)의 전파(傳播)와 동화(同化)에 대한 포괄적(包括的)인 도식(圖式)으로 표시(表示)할 수 있도록 설정(設定)하고 또 시행(施行)되었다. 2보(二報), 3보(三報), 4보(四報)에서는 데이터 뱅크에 수집(蒐集) 및 축적(蓄積)된 데이터의 일반적(一般的)인 기술(記述)을 적시(摘示)하였다. (1) 과학(科學)과 기술(技術)의 정보유통(情報流通)에 있어서 국가적(國家的) 회합(會合)의 역할(役割)(Garvey; 4보(報)) 국가적(國家的) 회합(會合)은 투고(投稿)와 이로 인한 잡지중(雜誌中) 게재간(揭載間)의 상대적(相對的)인 오랜 기간(期間)동안 이러한 연구(硏究)가 공개매체(公開媒體)로 인하여 일시적(一時的)이나마 게재여부(揭載如否)의 불명료성(不明瞭性)을 초래(招來)하기 전(前)에 과학연구(科學硏究)의 초기전파(初期傳播)를 위하여 먼저 행한 주요(主要) 사례(事例)와 마지막의 비정형매체(非定形媒體)의 양자(兩者)를 항상 조직화(組織化)하여 주는 전체적(全體的)인 유통과정(流通過程)에 있어서 명확(明確)하고도 중요(重要)한 기능(機能)을 갖는다는 것을 알 수 있었다. (2) 잡지(雜誌)에 게재(揭載)된 정보(情報)의 생산(生産)과 관련(關聯)되는 정보(情報)의 전파과정(傳播過程)(Garvey; 1보(報)). 이 연구(硏究)를 위해서 우리는 정보유통과정(情報流通過程)을 따라 많은 노력(努力)을 하였는데, 여기서 유통과정(流通過程)의 인상적(印象的)인 면목(面目)은 특별(特別)히 연구(硏究)로부터의 정보(情報)는 잡지(雜誌)에 게재(揭載)되기까지 진정으로는 공개적(公開的)이 못된다는 것과 이러한 사실(事實)은 선진연구(先進硏究)가 자주 시대(時代)에 뒤떨어지게 된다는 것을 발견할 수 있었다. 경험(經驗)이 많은 정보(情報)의 수요자(需要者)는 이러한 폐물화(廢物化)에 매우 민감(敏感)하며 자기(自己) 연구(硏究)에 당면한, 진행중(進行中)이거나 최근(最近) 완성(完成)된 연구(硏究)에 대하여 정보(情報)를 얻기 위한 모든 수단(手段)을 발견(發見)코자 하였다. 예를 들어, 이들은 잡지(雜誌)에 보문(報文)을 발표(發表)하기 전(前)에 발생(發生)하는 정보전파과정(情報傳播過程)을 통하여 유루(遺漏)될지도 모르는 정보(情報)를 얻기 위하여 한 잡지(雜誌)나 2차자료(二次資料) 또는 전형적(典型的)으로 이용(利用)되는 다른 잡지류중(雜誌類中)에서 당해정보(當該情報)가 발견(發見)되기를 기다리지 않는다는 것이다. (3) "정보생산 과학자(情報生産 科學者)"에 의한 정보전파(情報傳播)의 계속성(繼續性)(이 연구(硏究) 시리이즈의 결과(結果)는 본고(本稿)의 주내용(主內容)으로 되어 있다.) 1968/1969년(年)부터 1970/1971년(年)의 이년기간(二年期間)동안 보문(報文)을 낸 과학자(科學者)(1968/1969년(年) 잡지중(雜誌中)에 "질이 높은" 보문(報文)을 발표(發表)한)의 약 2/3는 1968/1969의 보문(報文)과 동일(同一)한 대상영역(對象領域)의 연구(硏究)를 계속(繼續) 수행(遂行)하였다. 그래서 우리는 본연구(本硏究)에 오른 대부분(大部分)의 저자(著者)가 정상적(正常的)인 과학(科學), 즉 연구수행중(硏究遂行中) 의문(疑問)에 대한 완전(完全)한 해답(解答)을 얻게 되는 가장 중요(重要)한 추구(追求)로서 Kuhn(제5보(第5報))에 의하여 기술(技術)된 방법(방법)으로 과학(연구)(科學(硏究))을 실행(實行)하였음을 알았다. 최근(最近)에 연구(硏究)를 마치고 그 결과(結果)를 보문(報文)으로서 발표(發表)한 이들 과학자(科學者)들은 다음 단계(段階)로 해야 할 사항(事項)에 대하여 선행(先行)된 동일견해(同一見解)를 가진 다른 연구자(硏究자)들의 연구(硏究)와 대상(對象)에 밀접(密接)하게 관련(關聯)되고 있다. 이 계속성(繼續性)의 효과(效果)에 대한 지표(指標)는 보문(報文)과 동일(同一)한 영역(領域)에서 연구(硏究)를 계속(繼續)한 저자(著者)들의 약 3/4은 선행(先行) 보문(報文)에 기술(技術)된 연구결과(硏究結果)에서 직접적(直接的)으로 새로운 연구(硏究)가 유도(誘導)되었음을 보고(報告)한 사항(事項)에 반영(反映)되어 있다. 그렇지만 우리들의 데이터는 다음 영역(領域)으로 기대(期待)하지 않은 전환(轉換)을 일으킬 수도 있음을 보여주고 있다. 동일(同一) 대상(對象)에서 연구(硏究)를 속행(續行)하였던 저자(著者)들의 1/5 이상(以上)은 뒤에 새로운 영역(領域)으로 연구(硏究)를 전환(轉換)하였고 또한 이 영역(領域)에서 연구(硏究)를 계속(繼續)하였다. 연구영역(硏究領域)의 이러한 변화(變化)는 연구자(硏究者)의 일반(一般) 정보유통(情報流通) 패턴에 크게 변화(變化)를 보이지는 않는다. 즉 새로운 지적(知的) 문제(問題)에 대한 변화(變化)에서 야기(惹起)되는 패턴에 있어서 저자(著者)들은 오래된 문제(問題)의 방법(方法)과 기술(技術)을 새로운 문제(問題)로 맞추려 한다. 과학사(科學史)의 최근(最近) 해석(解釋)(Hanson: 6보(報))에서 예기(豫期)되었던 바와 같이 정상적(正常的)인 과학(科學)의 계속성(繼續性)은 항상 절대적(絶對的)이 아니며 "과학지식(科學知識)"의 첫발자욱은 예전 연구영역(硏究領域)의 대상(對象)에 관계(關係)없이 나타나는 다른 영역(領域)으로 내딛게 될지도 모른다. 우리들의 연구(硏究)에서 저자(著者)의 1/3은 동일(同一) 영역(領域)의 대상(對象)에서 속계적(續繼的)인 연구(硏究)를 수행(遂行)치 않고 새로운 영역(領域)으로 옮아갔다. 우리는 이와 같은 데이터를 (a) 저자(著者)가 각개과학자(各個科學者)의 활동(活動)을 통하여 집중적(集中的)인 과학적(科學的) 노력(努力)을 시험(試驗)할 때 각자(各自)의 연구(硏究)에 대한 많은 양(量)의 계속성(繼續性)이 어떤 진보중(進步中)의 과학분야(科學分野)에서도 나타난다는 것과 (b) 이 계속성(繼續性)은 과학(科學)에 대한 집중적(集中的) 진보(進步)의 필요적(必要的) 특질(特質)이라는 것을 의미한다. 또한 우리는 이 계속성(繼續性)과 관련(關聯)되는 유통문제(流通問題)라는 새로운 대상영역(對象領域)으로 전환(轉換)할 때 연구(硏究)의 각단계(各段階)의 진보(進步)와 새로운 목적(目的)으로 전환시(轉換時) 양자(兩者)가 다 필요(必要)로 하는 각개(各個) 과학자(科學者)의 정보수요(情報需要)를 위한 시간(時間) 소비(消費)라는 것을 탐지(探知)할 수 있다. 이러한 관찰(觀察)은 정보(情報)의 선택제공(選擇提供)시스팀이 현재(現在) 필요(必要)로 하는 정보(情報)의 만족(滿足)을 위하여는 효과적(效果的)으로 매우 융통성(融通性)을 띠어야 한다는 것을 암시(暗示)하는 것이다. 본고(本稿)의 시리이즈에 기술(記述)된 전정보유통(全情報流通) 과정(過程)의 재검토(再檢討) 결과(結果)는 과학자(科學者)들이 항상 그들의 요구(要求)를 조화(調和)시키는 신축성(伸縮性)있는 유통체제(流通體制)를 발전(發展)시켜 왔다는 것을 시사(示唆)해 주고 있다. 이 시스팀은 정보전파(情報傳播) 사항(事項)을 중심(中心)으로 이루어 지며 또한 이 사항(事項)의 대부분(大部分)의 참여자(參與者)는 자기자신(自己自身)이 과학정보(科學情報) 전파자(傳播者)라는 기본적(基本的)인 정보전파체제(情報傳播體制)인 것이다. 그러나 이 과정(過程)의 유통행위(流通行爲)에서 살펴본 바와 같이 우리는 대부분(大部分)의 정보전파자(情報傳播者)가 역시 정보(情報)의 동화자(同化者)-다시 말해서 과학정보(科學情報)의 생산자(生産者)는 정보(情報)의 이용자(利用者)라는 것을 알 수 있다. 이 연구(硏究)에서 전형적(典型的)인 과학자((科學者)는 과학정보(科學情報)의 생산(生産)이나 전파(傳播)의 양자(兩者)에 연속적(連續的)으로 관계(關係)하고 있음을 보았다. 만일(萬一) 연구자(硏究者)가 한 편(編)의 연구(硏究)를 완료(完了)한다면 이 연구자(硏究者)는 다음에 무엇을 할 것이냐 하는 관념(觀念)을 갖게 되고 따라서 "완료(完了)된" 연구(硏究)에 관한 정보(情報)를 이용(利用)하여 동시(同時)에 새로운 일을 시작(始作)하게 된다. 예를 들어, 한 과학자(科學者)가 동일(同一) 영역(領域)의 다른 동료연구자(同僚硏究者)에게 완전(完全)하며 이의(異議)에 방어(防禦)할 수 있는 보고서(報告書)를 제공(提供)할 수 있는 단계(段階)에 도달(到達)하였다면 우리는 이 과학자(科學者)가 정보유통과정(情報流通過程)에서 많은 역할(役割)을 해낼 수 있다는 것을 알 것이다. 즉 이 과학자(科學者)는 다른 과학자(科學者)들에게 최신(最新)의 과학적(科學的) 결과(結果)를 제공(提供)할 때 하나의 과학정보(科學情報) 전파자(傳播者)가 되며, 이 연구(硏究)의 의의(意義)와 타당성(妥當性)에 관한 논평(論評)이나 비평(批評)을 동료(同僚)로부터 구(求)하는 관점(觀點)에서 보면 이 과학자(科學者)는 하나의 정보탐색자(情報探索者)가 된다. 또한 장래(將來)의 이용(利用)을 위하여 증정(贈呈)이나 동화(同化)한 이 정보(情報)로부터 피이드백을 받아 드렸을 때의 범주(範疇)에서 보면 (잡지(雜誌)에 투고(投稿)하기 위하여 원고(原稿)를 작성(作成)하는 경우에 있어서와 같이) 과학자(科學者)는 하나의 정보이용자(情報利用者)가 되고 이러한 모든 가능성(可能性)에서 정보생산자(情報生産者)는 다음 정보생산(情報生産)에 이미 들어가 있다고 볼 수 있다(저자(著者)들의 2/3는 보문(報文)이 게재(揭載)되기 전(前)에 이미 새로운 연구(硏究)를 시작(始作)하였다). 과학자(科學者)가 자기연구(自己硏究)를 마치고 예비보고서(豫備報告書)를 만든 후(後) 자기연구(自己硏究)에 관한 정보(情報)의 전파(傳播)를 계속하게 되는데 이와 관계(關係)되는 일반적(一般的)인 패턴을 보면 소수(少數)의 동료(同僚)그룹에 출석(出席)하는 경우 (예로 지역집담회)(地域集談會))와 대중(大衆) 앞에서 행(行)하는 경우(예로 국가적 회합(國家的 會合)) 등이 있다. 그러는 동안에 다양성(多樣性) 있는 성문보고서(成文報告書)가 이루어진다. 그러나 과학자(科學者)들이 자기연구(自己硏究)를 위한 주정보전파목표(主情報傳播目標)는 과학잡지중(科學雜誌中)에 게재(揭載)되는 보문(報文)이라는 것이 명확(明確)한 사실(事實)인 것이다. 이러한 목표(目標)에 도달(到達)할 때까지의 각(各) 정보전파단계(情報傳播段階)에서 과학자(科學者)들은 목표달성(目標達成)을 위하여 청중(聽衆), 자기동화(自己同化)된 정보(情報) 및 이미 이용(利用)된 정보(情報)로부터 피이드백을 탐색(探索)하게 된다. 우리가 본고(本稿)의 시리이즈중(中)에 표현(表現)하려 했던 바와 같이 이러한 활동(活動)은 조사수임자(調査受任者)의 의견(意見)이 원고(原稿)에 반영(反映)되고 또 그 원고(原稿)가 잡지게재(雜誌揭載)를 위해 수리(受理)될 때까지 계속적(繼續的)으로 정보(情報)를 탐색(探索)하는 과학자(科學者)나 기타(其他)사람들에게 효과적(效果的)이었다. 원고(原稿)가 수리(受理)되면 그 원고(原稿)의 저자(著者)들은 그 보문(報文)의 주내용(主內容)에 대하여 적극적(積極的)인 정보전파자(情報傳播者)로서의 역할(役割)을 종종 중지(中止)하는 일이 있는데 이때에는 저자(著者)들의 역할(役割)이 변화(變化)하는 것을 볼 수 있었다. 즉 이 저자(著者)들은 일시적(一時的)이긴 하나 새로운 일을 착수(着手)하기 위하여 정보(情報)의 동화자(同化者)를 찾게 된다. 또한 전(前)에 행한 일에 대한 의견(意見)이나 비평(批評)이 새로운 일에 영향(影響)을 끼치게 된다. 동시(同時)에 새로운 과학정보생산(科學情報生産) 과정(過程)에 들어가게 되고 현재(現在) 진행중(進行中)이거나 최근(最近) 완료(完了)한 연구(硏究)에 대한 정보(情報)를 항상 찾게 된다. 활발(活潑)한 연구(硏究)를 하는 과학자(科學者)들에게는, 동화자(同化者)로서의 역할(役割)과 전파자(傳播者)로서의 역할(役割)을 분리(分離)시킨다는 것은 실제적(實際的)은 못된다. 즉 후자(後者)를 완성(完成)하기 위해서는 전자(前者)를 이용(利用)하게 된다는 것이다. 과학자(科學者)들은 한 단계(段階)에서 한 전파자(傳播者)로서의 역할(役割)이 뚜렷하나 다른 단계(段階)에서는 정보교환(情報交換)이 기본적(基本的)으로 정보동화(情報同化)에 직결(直結)되고 있는 것이다. 정보전파자(情報傳播者)와 정보동화자간(情報同化者間)의 상호관계(相互關係)(또는 정보생산자(情報生産者)와 정보이용자간(情報利用者間))는 과학(科學)에 있어서 하나의 필수양상(必修樣相)이다. 과학(科學)의 유통구조(流通構造)가 전파자(傳播者)(이용자(利用者)로서의 역할(役割)보다는)의 필요성(必要性)에서 볼 때 복잡(複雜)하고 다이나믹한 시스팀으로 구성(構成)된다는 사실(事實)은 과학(科學)의 발전과정(發展過程)에서 필연적(必然的)으로 나타난다. 이와 같은 사실(事實)은 과학정보(科學情報)의 전파요원(傳播要員)이 국가적 회합(國家的 會合)에서 자기연구(自己硏究)에 대한 정보(情報)의 전파기회(傳播機會)를 거절(拒絶)하고 따라서 전파정보(電波情報)를 판단(判斷)하고 선별(選別)하는 것을 감소(減少)시키며 결과적(結果的)으로 잡지(雜誌)나 단행본(單行本)에서 비평(批評)을 하고 추고(推敲)하는 것이 배제(排除)될 때는 유형적(有形的) 과학(科學)은 급속(急速)히 비과학성(非科學性)을 띠게 된다는 것을 Lysenko의 생애(生涯)에 대한 Medvedev의 기술중(記述中)[7]에 지적(指摘)한 것과 관계(關係)되고 있다.

• Journal of Intelligence and Information Systems
• /
• v.25 no.4
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• pp.1-33
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• 2019

The small and medium sized enterprises (hereinafter SMEs) are already at a competitive disadvantaged when compared to large companies with more abundant resources. Manufacturing SMEs not only need a lot of information needed for new product development for sustainable growth and survival, but also seek networking to overcome the limitations of resources, but they are faced with limitations due to their size limitations. In a new era in which connectivity increases the complexity and uncertainty of the business environment, SMEs are increasingly urged to find information and solve networking problems. In order to solve these problems, the government funded research institutes plays an important role and duty to solve the information asymmetry problem of SMEs. The purpose of this study is to identify the differentiating characteristics of SMEs that utilize the public information support infrastructure provided by SMEs to enhance the innovation capacity of SMEs, and how they contribute to corporate performance. We argue that we need an infrastructure for providing information support to SMEs as part of this effort to strengthen of the role of government funded institutions; in this study, we specifically identify the target of such a policy and furthermore empirically demonstrate the effects of such policy-based efforts. Our goal is to help establish the strategies for building the information supporting infrastructure. To achieve this purpose, we first classified the characteristics of SMEs that have been found to utilize the information supporting infrastructure provided by government funded institutions. This allows us to verify whether selection bias appears in the analyzed group, which helps us clarify the interpretative limits of our study results. Next, we performed mediator and moderator effect analysis for multiple variables to analyze the process through which the use of information supporting infrastructure led to an improvement in external networking capabilities and resulted in enhancing product competitiveness. This analysis helps identify the key factors we should focus on when offering indirect support to SMEs through the information supporting infrastructure, which in turn helps us more efficiently manage research related to SME supporting policies implemented by government funded institutions. The results of this study showed the following. First, SMEs that used the information supporting infrastructure were found to have a significant difference in size in comparison to domestic R&D SMEs, but on the other hand, there was no significant difference in the cluster analysis that considered various variables. Based on these findings, we confirmed that SMEs that use the information supporting infrastructure are superior in size, and had a relatively higher distribution of companies that transact to a greater degree with large companies, when compared to the SMEs composing the general group of SMEs. Also, we found that companies that already receive support from the information infrastructure have a high concentration of companies that need collaboration with government funded institution. Secondly, among the SMEs that use the information supporting infrastructure, we found that increasing external networking capabilities contributed to enhancing product competitiveness, and while this was no the effect of direct assistance, we also found that indirect contributions were made by increasing the open marketing capabilities: in other words, this was the result of an indirect-only mediator effect. Also, the number of times the company received additional support in this process through mentoring related to information utilization was found to have a mediated moderator effect on improving external networking capabilities and in turn strengthening product competitiveness. The results of this study provide several insights that will help establish policies. KISTI's information support infrastructure may lead to the conclusion that marketing is already well underway, but it intentionally supports groups that enable to achieve good performance. As a result, the government should provide clear priorities whether to support the companies in the underdevelopment or to aid better performance. Through our research, we have identified how public information infrastructure contributes to product competitiveness. Here, we can draw some policy implications. First, the public information support infrastructure should have the capability to enhance the ability to interact with or to find the expert that provides required information. Second, if the utilization of public information support (online) infrastructure is effective, it is not necessary to continuously provide informational mentoring, which is a parallel offline support. Rather, offline support such as mentoring should be used as an appropriate device for abnormal symptom monitoring. Third, it is required that SMEs should improve their ability to utilize, because the effect of enhancing networking capacity through public information support infrastructure and enhancing product competitiveness through such infrastructure appears in most types of companies rather than in specific SMEs.

• Journal of Korean Society of Forest Science
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• v.34 no.1
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• pp.31-46
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• 1977

The study was made to give some helpful information for policy-making on ornamental tree cultivation by doing a survey on general situations, management analysis, and future prospects of the ornamental tree growing. The study was carried out through literature studies related to the subject, questionaire surveys, and on-the-spot investigation. The questionaire surveys could be divided into two parts: pre-questionaire survey and main-questionaire survey. In the pre-questionaire survey, the researchers intended to identify the total number of ornamental tree growers, cultivation areas in size and their locations. The questionaires were sent to each town and county administration authorities, forest cooperatives, and related organizations through-out the nation. The main-questionaires were prepared for detailed study and the questionaires were sent to 200 tree growers selected by option by taking considerations of the number of tree growers and the size of cultivating areas in regions. The main findings and some information obtained in the survey were as follows: 1. The total land for ornamental tree growing was amounted to 1,873.02 hectares and the number of cultivators was totaled to 2,717. 2. The main occupations of the ornamental tree growers were found in horticulture (41.9%), agronomy (25.9%), officialdom (11.3%), animal husbandry (6.5%), business circle(4.8%), and forestry (3.2%) in sequence. 3. The ornamental trees were cultivated mostly upperland (54.8), forest land (19.4%), rice paddy (11.3%) and others. 4. The educational training of the tree growers seemed quite high. The results of the survey indicated that a large number of tree growers was occupied by college graduates (38.7%), and then high school graduates (34.7%), middle school graduates (12.9%) in order. 5. The tree farming was undertaken as a side-job (41.9%) rather than main-job (23.4%), but a few of respondents rated as subsidiary-job (18.6%). 6. The management status classified by the rate of hired labors used was likely to belong to three categories: independant enterprise management (41.9%); half independant management (31.5%); and self-management (32.4%). 7. The majority of the tree growers sold their products to the consumers through middle-man channel (48.4%), or directly to the house-holder and detailers (13.7%), but a few of the respondents answered that they disposed of their products by bidding (11.2%) or by direct selling to the contractors (4.8%). 8. The channel cf marketing seemed somewhat complicated. The results of the survey were as: (1) producers ${\rightarrow}$consumers (22.6%) (2) producers ${\rightarrow}$field middle-men${\rightarrow}$consumers (33.1%) (3) producers ${\rightarrow}$field middle-men${\rightarrow}$first stage brokers${\rightarrow}$consumers (15.3%) (4) producers ${\rightarrow}$field middle-men${\rightarrow}$second stage middle-men${\rightarrow}$brokers${\rightarrow}$consumers (5.7%) (5) producers${\rightarrow}$field middle-men${\rightarrow}$third stage middle-men${\rightarrow}$second stage middlemen${\rightarrow}$brokers${\rightarrow}$consumers (4.8%) 9. It was responded that the margin for each stage of middle-men or brokers was assumed to be 30-50%(33.1%), 20-30%(32.3%), 50-100%(9.7%), and 100-200%(2.4%) in sequence. 10. The difference between the delivery price of consumers and field selling price of the producers seemed quite large. Majority of producers responded that they received half a price compared to the consumer's prices. 11. About two thirds of the respondents opposed to the measure of "Law on Preservation and Utilization of Agricultural Land" in which says that all the ornamental trees grown on flat agricultural lands less than 8 degrees in slope must be transplanted within three years to other places more than 8 degrees in slope. 12. The tree growers said that they have paid rather high land taxes than they ought to pay (38.7%), but come responded that land tax seemed to be appropriate (15.3%), and half of the respondents answered "not known". 13. The measures for the standardization of ornamental trees by size were backed up by a large number of respondents (57.3%), but one third of the respondents showed negative answer (29.8%). 14. About half of the respondents favored the systematic marketing through organization such as forest cooperatives (54%), but quite a few respondents opposed to organizing the systematic marketing channel (36.3%). 15. The necessary measures for permission in ornamental tree cultivation was rejected by a large number of respondents (49.2%) than those of favored (43.6%).

• Journal of Korean Society of Forest Science
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• v.20 no.1
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• pp.1-44
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• 1973

Needless to say, the management of national forest in all countries is very important in view of the national mission and management purposes. Korean national forest is also in particular significant in promoting national economy for the continuous increasing of the demand for wood, conservation of the land and social welfare. But there's no denying the fact that the leading aim of the Korean forest policy has been based upon the conservation of forest resources and recovery of land conservation function instead of improvement of the forest productive capacity. Therefore, the management of national forest should be aimed as an industry in the chain of the Korean national economy. And the increment of the forest productive capacity based on rationalized forest management is also urgently needed. Not only the increment of the timber production but also the establishment of the good forest in quality and quantity are to bring naturally many functions of conservation and other public benefits. In 1908 Korean national forest was historically established for the first time as a result of the notification for ownership, and was divided into two kinds in 1911-1924, such as indisposable national forest for land conservation, forest management, scientific research and public welfare, and the other national forest to be disposed. Indisposable forest is mostly under the jurisdiction of national forest stations (Chungbu, Tongbu, Nambu), and the tother national forests are under custody of respective cities and provinces, and under custody of the other government authorities. As of the end of 1971, national forest land is 19.5% (1,297,708 ha) of the total forest land area, but growing stock is 50.1% ($35,406,079m^3$) of the total forest growing stock, and timber production of national forest is 23.6% ($205,959m^3$) of the year production of total timber in Korea. Accordingly, it is the important fact that national forest occupies the major part of Korean forestry. The author positively affirms that success or failure of the management of national forest controls rise or fall of forestry in Korea. All functions of forest are very important, but among others the function of timber production is most important especially in Korea, that unavoidably imports a large quantity of foreign wood every year (in 1971 import of foreign wood-$3,756,000m^3$, 160,995,000 dollars). So, Korea urgently needs the improvement of forest productive capacity in national forest. But it is difficult that wood production meets the rapid increase of demand for wood to the development of economy, because production term of forestry is long, so national forest management should be rationalized by the effective investment and development of forestry techniques in the long view. Although Korean national forest business has many difficulties in the budget, techniques and the lack of labour due to outflow of rural village labour by development of national economy, and the increase of labour wages and administrative expenses etc. the development of national forest depends on adoption of the suitable forest techniques and management adapted for social and economical development. In this view point the writer has investigated and analyzed the status of the management of national forest in Korea to examine the irrational problems and suggest an improvement plan. The national forestry statistics cited in this study is based on the basic statistics and the statistics of the forest business as of the end of 1971 published by Office of Forestry, Republic of Korea, and the other depended on the data presented by the national forest stations. The writer wants to propose as follows (seemed to be helpful in improvement of Korean national forest management). 1) In the organization of national forest management, more national forest stations should be established to manage intensively, and the staff of working plan officials should be strengthened because of the importance of working plan. 2) By increasing the staff of protection officials, forest area assigned for each protection official should be decreased to 1,000-2,000 ha. 3) The frequent personnel changes of supervisor of national forest station(the responsible person on-the-spot) obstructs to accomplish the consistent management plan. 4) In the working plan drafting for national forest, basic investigations should be carefully practiced with sufficient expenditure and staff not to draft unreal working plan. 5) The area of working-unit should be decreased to less than 2,000 ha on the average for intensive management and the principle of a working-unit in a forest station should be realized as soon as possible. 6) Reforestation on open land should be completed in a short time with a debt of the special fund(a long term loan), and the land on which growing hardwood stands should be changed with conifers to increase productivity per unit area, and at the same time techical utilization method of hardwood should be developed. 7) Expenses of reforestation should be saved by mechanization and use of chemicals for reforestation and tree nursery operation providing against the lack of labour in future. 8) In forest protection, forest fire damage is enormous in comparison with foreign countries, accordingly prevention system and equipment should be improved, and also the minimum necessary budget should be counted up for establishment and manintenance of fire-lines. 9) Manufacture production should be enlarged to systematize protection, processing and circulation of forest business, and, by doing this, mich benefit is naturally given for rural people. 10) Establishment and arrangement of forest road networks and erosion control work are indispensable for the future development of national forest itself and local development. Therefore, these works should be promoted by the responsibility of general accounting instead of special accounting. 11) Mechanization of forest works should be realized for exploiting hinterlands to meet the demand for timber increased and for solving lack of labour, consequently it should promote import of forest machines, home production, training for operaters and careful adminitration. 12) Situation of labour in future will grow worse. Therefore, the countermeasure to maintain forest labourers and pay attention to public welfare facilities and works should be considered. 13) Although the condition of income and expenditure grows worse because of economical change, the regular expenditure should be fixed. So part of the surplus fund, as of the end of 1971, should be established for the fund, and used for enlarging reforestation and forest road networks(preceding investment in national forest).

• Korean small business review
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• v.31 no.4
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• pp.67-93
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• 2009

The purpose of this paper is to explore the relations between financial constraints and dividend smoothing of innovative small and medium sized enterprises(SMEs) listed on Korea Securities Market and Kosdaq Market of Korea Exchange. The innovative SMEs is defined as the firms with high level of R&D intensity which is measured by (R&D investment/total sales) ratio, according to Chauvin and Hirschey (1993). The R&D investment plays an important role as the innovative driver that can increase the future growth opportunity and profitability of the firms. Therefore, the R&D investment have large, positive, and consistent influences on the market value of the firm. In this point of view, we expect that the innovative SMEs can adjust dividend payment faster than the noninnovative SMEs, on the ground of their future growth opportunity and profitability. And also, we expect that the financial unconstrained firms can adjust dividend payment faster than the financial constrained firms, on the ground of their financing ability of investment funds through the market accessibility. Aivazian et al.(2006) exert that the financial unconstrained firms with the high accessibility to capital market can adjust dividend payment faster than the financial constrained firms. We collect the sample firms among the total SMEs listed on Korea Securities Market and Kosdaq Market of Korea Exchange during the periods from January 1999 to December 2007 from the KIS Value Library database. The total number of firm-year observations of the total sample firms throughout the entire period is 5,544, the number of firm-year observations of the dividend firms is 2,919, and the number of firm-year observations of the non-dividend firms is 2,625. About 53%(or 2,919) of these total 5,544 observations involve firms that make a dividend payment. The dividend firms are divided into two groups according to the R&D intensity, such as the innovative SMEs with larger than median of R&D intensity and the noninnovative SMEs with smaller than median of R&D intensity. The number of firm-year observations of the innovative SMEs is 1,506, and the number of firm-year observations of the noninnovative SMEs is 1,413. Furthermore, the innovative SMEs are divided into two groups according to level of financial constraints, such as the financial unconstrained firms and the financial constrained firms. The number of firm-year observations of the former is 894, and the number of firm-year observations of the latter is 612. Although all available firm-year observations of the dividend firms are collected, deletions are made in the case of financial industries such as banks, securities company, insurance company, and other financial services company, because their capital structure and business style are widely different from the general manufacturing firms. The stock repurchase was involved in dividend payment because Grullon and Michaely (2002) examined the substitution hypothesis between dividends and stock repurchases. However, our data structure is an unbalanced panel data since there is no requirement that the firm-year observations data are all available for each firms during the entire periods from January 1999 to December 2007 from the KIS Value Library database. We firstly estimate the classic Lintner(1956) dividend adjustment model, where the decision to smooth dividend or to adopt a residual dividend policy depends on financial constraints measured by market accessibility. Lintner model indicates that firms maintain stable and long run target payout ratio, and that firms adjust partially the gap between current payout rato and target payout ratio each year. In the Lintner model, dependent variable is the current dividend per share(DPS_t), and independent variables are the past dividend per share(DPS_t-1) and the current earnings per share(EPS_t). We hypothesized that firms adjust partially the gap between the current dividend per share(DPS_t) and the target payout ratio(Ω) each year, when the past dividend per share(DPS_t-1) deviate from the target payout ratio(Ω). We secondly estimate the expansion model that extend the Lintner model by including the determinants suggested by the major theories of dividend, namely, residual dividend theory, dividend signaling theory, agency theory, catering theory, and transactions cost theory. In the expansion model, dependent variable is the current dividend per share(DPS_t), explanatory variables are the past dividend per share(DPS_t-1) and the current earnings per share(EPS_t), and control variables are the current capital expenditure ratio(CEA_t), the current leverage ratio(LEV_t), the current operating return on assets(ROA_t), the current business risk(RISK_t), the current trading volume turnover ratio(TURN_t), and the current dividend premium(DPREM_t). In these control variables, CEA_t, LEV_t, and ROA_t are the determinants suggested by the residual dividend theory and the agency theory, ROA_t and RISK_t are the determinants suggested by the dividend signaling theory, TURN_t is the determinant suggested by the transactions cost theory, and DPREM_t is the determinant suggested by the catering theory. Furthermore, we thirdly estimate the Lintner model and the expansion model by using the panel data of the financial unconstrained firms and the financial constrained firms, that are divided into two groups according to level of financial constraints. We expect that the financial unconstrained firms can adjust dividend payment faster than the financial constrained firms, because the former can finance more easily the investment funds through the market accessibility than the latter. We analyzed descriptive statistics such as mean, standard deviation, and median to delete the outliers from the panel data, conducted one way analysis of variance to check up the industry-specfic effects, and conducted difference test of firms characteristic variables between innovative SMEs and noninnovative SMEs as well as difference test of firms characteristic variables between financial unconstrained firms and financial constrained firms. We also conducted the correlation analysis and the variance inflation factors analysis to detect any multicollinearity among the independent variables. Both of the correlation coefficients and the variance inflation factors are roughly low to the extent that may be ignored the multicollinearity among the independent variables. Furthermore, we estimate both of the Lintner model and the expansion model using the panel regression analysis. We firstly test the time-specific effects and the firm-specific effects may be involved in our panel data through the Lagrange multiplier test that was proposed by Breusch and Pagan(1980), and secondly conduct Hausman test to prove that fixed effect model is fitter with our panel data than the random effect model. The main results of this study can be summarized as follows. The determinants suggested by the major theories of dividend, namely, residual dividend theory, dividend signaling theory, agency theory, catering theory, and transactions cost theory explain significantly the dividend policy of the innovative SMEs. Lintner model indicates that firms maintain stable and long run target payout ratio, and that firms adjust partially the gap between the current payout ratio and the target payout ratio each year. In the core variables of Lintner model, the past dividend per share has more effects to dividend smoothing than the current earnings per share. These results suggest that the innovative SMEs maintain stable and long run dividend policy which sustains the past dividend per share level without corporate special reasons. The main results show that dividend adjustment speed of the innovative SMEs is faster than that of the noninnovative SMEs. This means that the innovative SMEs with high level of R&D intensity can adjust dividend payment faster than the noninnovative SMEs, on the ground of their future growth opportunity and profitability. The other main results show that dividend adjustment speed of the financial unconstrained SMEs is faster than that of the financial constrained SMEs. This means that the financial unconstrained firms with high accessibility to capital market can adjust dividend payment faster than the financial constrained firms, on the ground of their financing ability of investment funds through the market accessibility. Futhermore, the other additional results show that dividend adjustment speed of the innovative SMEs classified by the Small and Medium Business Administration is faster than that of the unclassified SMEs. They are linked with various financial policies and services such as credit guaranteed service, policy fund for SMEs, venture investment fund, insurance program, and so on. In conclusion, the past dividend per share and the current earnings per share suggested by the Lintner model explain mainly dividend adjustment speed of the innovative SMEs, and also the financial constraints explain partially. Therefore, if managers can properly understand of the relations between financial constraints and dividend smoothing of innovative SMEs, they can maintain stable and long run dividend policy of the innovative SMEs through dividend smoothing. These are encouraging results for Korea government, that is, the Small and Medium Business Administration as it has implemented many policies to commit to the innovative SMEs. This paper may have a few limitations because it may be only early study about the relations between financial constraints and dividend smoothing of the innovative SMEs. Specifically, this paper may not adequately capture all of the subtle features of the innovative SMEs and the financial unconstrained SMEs. Therefore, we think that it is necessary to expand sample firms and control variables, and use more elaborate analysis methods in the future studies.

• Magazine of the Korean Society of Agricultural Engineers
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• v.11 no.4
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• pp.1775-1782
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• 1969

The results of the study on the consumptine use of irrigated water in paddy fields during the growing season of rice plants are summarized as follows. 1. Transpiration and evaporation from water surface. 1) Amount of transpiration of rice plant increases gradually after transplantation and suddenly increases in the head swelling period and reaches the peak between the end of the head swelling poriod and early period of heading and flowering. (the sixth period for early maturing variety, the seventh period for medium or late maturing varieties), then it decreases gradually after that, for early, medium and late maturing varieties. 2) In the transpiration of rice plants there is hardly any difference among varieties up to the fifth period, but the early maturing variety is the most vigorous in the sixth period, and the late maturing variety is more vigorous than others continuously after the seventh period. 3) The amount of transpiration of the sixth period for early maturing variety of the seventh period for medium and late maturing variety in which transpiration is the most vigorous, is 15% or 16% of the total amount of transpiration through all periods. 4) Transpiration of rice plants must be determined by using transpiration intensity as the standard coefficient of computation of amount of transpiration, because it originates in the physiological action.(Table 7) 5) Transpiration ratio of rice plants is approximately 450 to 480 6) Equations which are able to compute amount of transpiration of each variety up th the heading-flowering peried, in which the amount of transpiration of rice plants is the maximum in this study are as follows: Early maturing variety ; Y=0.658+1.088X Medium maturing variety ; Y=0.780+1.050X Late maturing variety ; Y=0.646+1.091X Y=amount of transpiration ; X=number of period. 7) As we know from figure 1 and 2, correlation between the amount evaporation from water surface in paddy fields and amount of transpiration shows high negative. 8) It is possible to calculate the amount of evaporation from the water surface in the paddy field for varieties used in this study on the base of ratio of it to amount of evaporation by atmometer(Table 11) and Table 10. Also the amount of evaporation from the water surface in the paddy field is to be computed by the following equations until the period in which it is the minimum quantity the sixth period for early maturing variety and the seventh period for medium or late maturing varieties. Early maturing variety ; Y=4.67-0.58X Medium maturing variety ; Y=4.70-0.59X Late maturing variety ; Y=4.71-0.59X Y=amount of evaporation from water surface in the paddy field X=number of period. 9) Changes in the amount of evapo-transpiration of each growing period have the same tendency as transpiration, and the maximum quantity of early maturing variety is in the sixth period and medium or late maturing varieties are in the seventh period. 10) The amount of evapo-transpiration can be calculated on the base of the evapo-transpiration intensity (Table 14) and Tablet 12, for varieties used in this study. Also, it is possible to compute it according to the following equations with in the period of maximum quantity. Early maturing variety ; Y=5.36+0.503X Medium maturing variety ; Y=5.41+0.456X Late maturing variety ; Y=5.80+0.494X Y=amount of evapo-transpiration. X=number of period. 11) Ratios of the total amount of evapo-transpiration to the total amount of evaporation by atmometer through all growing periods, are 1.23 for early maturing variety, 1.25 for medium maturing variety, 1.27 for late maturing variety, respectively. 12) Only air temperature shows high correlation in relation between amount of evapo-transpiration and climatic conditions from the viewpoint of Korean climatic conditions through all growing periods of rice plants. 2. Amount of percolation 1) The amount of percolation for computation of planning water requirment ought to depend on water holding dates. 3. Available rainfall 1) The available rainfall and its coefficient of each period during the growing season of paddy fields are shown in Table 8. 2) The ratio (available coefficient) of available rainfall to the amount of rainfall during the growing season of paddy fields seems to be from 65% to 75% as the standard in Korea. 3) Available rainfall during the growing season of paddy fields in the common year is estimated to be about 550 millimeters. 4. Effects to be influenced upon percolation by transpiration of rice plants. 1) The stronger absorbtive action is, the more the amount of percolation decreases, because absorbtive action of rice plant roots influence upon percolation(Table 21, Table 22) 2) In case of planting of rice plants, there are several entirely different changes in the amount of percolation in the forenoon, at night and in the afternoon during the growing season, that is, is the morning and at night, the amount of percolation increases gradually after transplantation to the peak in the end of July or the early part of August (wast or soil temperature is the highest), and it decreases gradually after that, neverthless, in the afternoon, it decreases gradually after transplantation to be at the minimum in the middle of August, and it increases gradually after that. 3) In spite of the increasing amount of transpiration, the amount of daytime percolation decreases gadually after transplantation and appears to suddenly decrease about head swelling dates or heading-flowering period, but it begins to increase suddenly at the end of August again. 4) Changs of amount of percolation during all growing periods show some variable phenomena, that is, amount of percolation decreases after the end of July, and it increases in end August again, also it decreases after that once more. This phenomena may be influenced complexly from water or soil temperature(night time and forenoon) as absorbtive action of rice plant roots. 5) Correlation between the amount of daytime percolation and the amount of transpiration shows high negative, amount of night percolation is influenced by water or soil temperature, but there is little no influence by transpiration. It is estimated that the amount of a daily percolation is more influenced by of other causes than transpiration. 6) Correlation between the amount of night percoe, lation and water or soil temp tureshows high positive, but there is not any correlation between the amount of forenoon percolation or afternoon percolation and water of soil temperature. 7) There is high positive correlation which is r=+0.8382 between the amount of daily percolation of planting pot of rice plant and amount and amount of daily percolation of non-planting pot. 8) The total amount of percolation through all growin. periods of rice plants may be influenced more from specific permeability of soil, water of soil temperature, and otheres than transpiration of rice plants.

• Journal of the Korean Wood Science and Technology
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• v.13 no.1
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• pp.19-62
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• 1985

This study was performed to investigate: (i) the bending processing properties of silk worm oak (Quercus acutissima Carr.) and Korean red pine (Pinus densiflora S. et Z.) by boiling and steaming treatments; (ii) the effects of interrelated factors - sapwood and heartwood, annual ring placement, softening temperature and time, moisture content. and wood defects on bending processing properties; (iii) the changing rates of bending radii after release from a tension strap, and (iv) the improving methods of bending process by treatment with chemicals. The size of specimens tested was $15{\times}15{\times}350mm$ for boiling and steaming treatments and $5{\times}10{\times}200mm$ for treatments with chemicals. The specimens were green for boiling treatments and dried to 15 percent for steaming treatments. The specimens for treatments with chemicals were soaked in saturated urea solution, 35 percent formaldehyde solution, 25 percent polyethylene glycol -400 solution, and 25 percent ammonium hydroxide solution for 5 days and immediately followed the bending process, respectively. The results obtained were as follows: 1. The internal temperature of silk worm oak and Korean red pine by boiling and steaming time was raised slowly to $30^{\circ}C$ but rapidly from $30^{\circ}C$ to $80-90^{\circ}C$ and then slowly from $80-90^{\circ}C$ to $100^{\circ}C$. 2. The softening time required to the final temperature was directly proportional to the thickness of specimen. The time required from $25^{\circ}C$ to $100^{\circ}C$ for 15mm-squared specimen was 9.6-11.2 minutes in silk worm oak and 7.6-8.1 minutes in Korean red pine. 3. The moisture content (M.C.) of specimen by steaming time was increased rapidly first 4 minutes in the both species, and moderately from 4 to 20 minutes and then slowly and constantly in silk worm oak, and moderately from 4 to 15 minutes and then slowly and constantly in Korean red pine. The M.C. of 15mm-squared specimen in 50 minutes of steaming was increased to 18.0 percent in the oak and 22.4 percent in the pine from the initial conditioned M.C. of 15 percent The rate of moisture adsorption measured was therefore faster in the pine than in the oak. 4. The mechanical properties of the both species were decreased significantly with the increase of boiling rime. The decrement by the boiling treatment for 60 minutes was measured to 36.6-45.0 percent in compressive strength, 12.5-17.5 percent in tensile strength, 31.6-40.9 percent in modulus of rupture, and 23.3-34.6 percent in modulus of elasticity. 5. The minimum bending radius (M.B.R.) of sapwood and heartwood was 60-80 mm and 90 mm in silk worm oak, and 260 - 300 mm and 280 - 300 mm in Korean red pine, respectively. Therefore, the both species showed better bending processing properties in sapwood than in heartwood. 6. The M.B.R. of edge-grained and flat-grained specimen in suk worm oak was 60-80 mm, but the M.B.R. in Korean red pine was 240-280 mm and 260-360 mm, respectively. Comparing the M.B.R. of edge-grained with flat-grained specimen, in the pine the edge-grained showed better bending processing property than the flat-grained. 7. The bending processing properties of the both species were improved by the rising of softening temperature from $40^{\circ}C$ to $100^{\circ}C$. The minimum softening temperature for bending was $90^{\circ}C$ in silk worm oak and $80^{\circ}C$ in Korean red pine, and the dependency of softening temperature for bending was therefore higher in the oak than in the pine. 8. The bending processing properties of the both species were improved by the increase of softening time as well as temperature, but even after the internal temperature of specimen reaching to the final temperature, somewhat prolonged softening was required to obtain the best plastic conditions. The minimum softening time for bending of 15 mm-squared silk worm oak and Korean red pine specimen was 15 and 10 minutes in the boiling treatment, and 30 and 20 minutes in the steaming treatment, respectively. 9. The optimum M.C. for bending of silk worm oak was 20 percent, and the M.C. above fiber saturation point rather degraded the bending processing property, whereas the optimum M.C. of Korean red pine needed to be above 30 percent. 10. The bending works in the optimum conditions obtained as seen in Table 24 showed that the M.B.R. of silk worm oak and Korean red pine was 80 mm and 240 mm in the boiling treatment, and 50 mm and 280 mm in the steaming treatment, respectively. Therefore, the bending processing property of the oak was better in the steaming than in the boiling treatment, but that of the pine better in the boiling than in the steaming treatment. 11. In the bending without a tension strap, the radio r/t of the minimum bending radius t to the thickness t of silk worm oak and Korean red pine specimen amounted to 16.0 and 21.3 in the boiling treatment, and 17.3 and 24.0 in the steaming treatment, respectively. But in the bending with a tension strap, the r/t of the oak and the pine specimen decreased to 5.3 and 16.0 in t he boiling treatment, and 3.3 and 18.7 in the steaming treatment, respectively. Therefore, the bending processing properties of the both species were significantly improved by the strap. 12. The effect of pin knot on the degradation of bending processing property was very severe in silk worm oak by side, e.g. 90 percent of the oak specimens with pin knot on the concave side were ruptured when bent to a 100 mm radius but only 10 percent of the other specimens with pin knot on the convex side were ruptured. 13. The changing rate in the bending radius of specimen bent to a 300 mm radius after 30 days of exposure to room temperature conditions was measured to 4.0-10.3 percent in the boiling treatment and 13,0-15.0 percent in the steaming treatment. Therefore, the degree of spring back after release was higher in the steaming than in the boiling treatment. And the changing rate of moisture-proofing treated specimen by expoxy resin coating was only -1.0.0 percent. 14. Formaldehyde, 35 percent solution, and 25 percent polyethylene glycol-400 solution found no effect on the plasticization of the both species, but saturated urea solution and 25 percent ammonium hydroxide solution found significant effect in comparison to non-treated specimen. But the effect of the treatment with chemicals alone was inferior to that of the steaming treatment, and the steaming treatment after the treatment with chemicals improved 10-24 percent over the bending processing property of steam-bent specimen. 15. Three plasticity coefficients - load-strain coefficient, strain coefficient, and energy coefficient - were evaluated to be appropriate for the index of bending processing property because the coefficients had highly significant correlation with the bending radius. The fitness of the coefficients as the index was good at load-strain coefficient, energy coefficient, and strain coefficient, in order.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.3
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• pp.1-40
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• 1965

To measure variations in some of the important agronomic characteristics of rice varieties under shifting of seedling dates, this study has been carried out at the Paddy Crop Division of Crop Experiment Station(then Agricultural Experiment Station) in Suwon for the period of three years 1958 to 1960. The varieties used in this study were Kwansan, Suwon ＃82, Mojo, Paltal and Chokwang, which have the different agronomic characteristics such as earliness and plant type. Seeds of each variety were sown at 14 different dates in 10-day interval starting on March 2. The seedlings were grown on seed bed for 30, 40, 50, 60, 70 and 80 days, respectively. The results of this study are as follows: A. Heading dates. 1. As the seeding date was delayed, the heading dates was almost proportionally delayed. The degree of delay was higher in early varieties and lower in late varieties and the longer the seedling stage, the more delayed the heading date. 2. Number of days to heading was proportionally lessened as seeding was delayed in all the varieties but the magnitude varied depending upon variety. In other words, the required period for heading in case of late planting was much shortened in late variety compared with early one. Within a variety, the number of days to heading was less shortened as the seedling stage was prolonged. Early variety reached earlier than late variety to the marginal date for the maximum shortening of days to heading and the longer the seeding stage, the limitted date came earlier. There was a certain limit in seeding date for shortening of days to heading as seeding was delayed, and days to heading were rather prolonged due to cold weather when seeded later than that date. 3. In linear regression equation, Y=a+bx obtained from the seeding dates and the number of days to heading, the coefficient b(shortening rate of days to heading) was closely correlated with the average number of days to heading. That is, the period from seeding to heading was more shortened in late variety than early one as seeding was delayed. 4. To the extent that the seedling stage is not so long and there is a linear relationship between delay of seeding and shortening of days to heading, it might be possible to predict heading date of a rice variety to be sown any date by using the linear regression obtained from variation of heading dates under the various seeding dates of the same variety. 5. It was found out that there was a close correlation between the numbers of days to heading in ordinary culture and the other ones. When a rice variety was planted during the period from the late part of March to the middle of June and the seedling ages were within 30 to 50 days, it could be possible to estimate heading date of the variety under late or early culture with the related data of ordinary culture. B. Maturing date. 6. Within (he marginal date for maturation of rice variety, maturing date was proportionally delayed as heading was delayed. Of course, the degree of delay depended upon varieties and seedling ages. The average air temperature (Y) during the ripening period of rice variety was getting lower as the heading date. (X) was delayed. Though there was a difference among varieties, in general, a linear regression equation(y=25.53-0.182X) could be obtained as far as heading date were within August 1 to September 13. 7. Depending upon earliness of a rice variety, the average air temperature during the ripening period were greatly different. Early variety underwent under 28$^{\circ}C$ in maximum while late variety matured under as low as 22$^{\circ}C$. 8. There was a highly significant correlation between the average air temperature (X) during the ripening period, and number of day (Y) for the maturation. And the relationship could be expressed as y=82.30-1.55X. When the average air temperature during the period was within the range of 18$^{\circ}C$ to 28$^{\circ}C$, the ripening period was shortened by 1.55 days with increase of 1$^{\circ}C$. Considering varieties, Kwansan was the highest in shortening the maturing period by 2.24 days and Suwon ＃82 was the lowest showing 0.78 days. It is certain that ripening of rice variety is accelerated at Suwon as the average air temperature increases within the range of 18$^{\circ}C$ to 28$^{\circ}C$. 9. Between number of days to heading (X) related to seeding dates and the accumulated average air temperature (Y) during the ripening period, a positive correlation was obtained. However, there was a little difference in the accumulated average air temperature during the ripening period even seeding dates were shifted to a certain extent. C. Culm- and ear-lengths. 10. In general all the varieties didn't show much variation in their culm-lengths in case of relatively early seeding but they trended to decrease the lengths as seeding was delayed. The magnitude of decreasing varied from young seedlings to old ones. Young seedlings which were seeded during May 21 to June 10 didn't decrease their culm-lengths, while seedlings old as 80 days decreased the length though under ordinary culture. 11. Variation in ear-length of rice varieties show the same trend as the culm-length subjected to the different seeding dates. When rice seedlings aged from 30 to 40 days, the ear-length remained constant but rice plants older than 40 days obviously decreased their ear-lengths. D. Number of panicles per hill. 12. The number of panicles per hill decreased up to a certain dates as seeding was delayed and then again increased the panicles due to the development of numerous tillers at the upper internodes. The seeding date to reach to the least number of panicles of rice variety depended upon the seedling ages. Thirty- to 40-day seedlings which were seeded during May 31 to June 10 developed the lowest number of panicles and 70- to 80-day seedlings sown for the period from April 11 to April 21 reached already to the minimum number of panicles. E. Number of rachillae. 13. To a certain seeding date, the number of rachillae didn't show any variation due to delay of seeding but it decreased remarkably when seeded later than the marginal date. 14. Variation in number of rachillae depended upon seedling ages. For example, 30- to 40-day old seedlings which, were originally seeded after May 31 started to decrease the rachillae. On the other hand, 80-day old seedlings which, were seeded on May 1 showed a tendency to decrease rachillae and the rice plant sown on May 31 could develop narrowly 3 or 4 panicles. F. Defective grain and 1.000-grain weights. 15. Under delay of the seeding dates, weight of the defective grains gradually increased till a certain date and then suddenly increased. These relationships could be expressed with two different linear regressions. 16. If it was assumed that the marginal date for ripening was the cross point of these two lines, the date seemed. closely related with seedling ages. The date was June 10- in 30- to 40-day old seedlings but that of 70- to 80-day old seedlings was May 1. Accordingly, the marginal date for ripening was getting earlier as the seedling stage was prolonged. 17. The 1.000-grain weight in ordinary culture was the heaviest and it decreased in both early and late cultures. G. Straw and rough rice weights. 18. Regardless of earliness of variety, rice plants under early culture which were seeded before March 22 or April 1 did not show much variation in straw weight due to seedling ages but in ordinary culture it gradually decreased and the degree was became greater in late culture. 19. Relationship between seeding dates (X) and grain weight related to varieties and seedling ages, could be expressed as a parabola analogous to a line (Y=77.28-7.44X$_1$-1.00lX$_2$). That is, grain yield didn't vary in early culture but it started to decrease when seeded later than a certain date, as seeding was delayed. The variation was much greater in cases of late planting and prolongation of seedling age. 20. Generally speaking, the relationship between grain yield (Y) and number of days to heading (X) was described with linear regression. However, the early varieties were the highest yielders within the range of 60 to 110, days to heading but the late variety greatly decreased its yield since it grows normally only under late culture. The grain yield, on the whole, didn't increase as number of days to heading exceeded more than 140 days.