• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2006년도 춘계학술대회
• /
• pp.485-488
• /
• 2006

In order to investigate the possibility of waste mushroom logs as biomass resource chemical and physical characteristics of normal woods and waste mushroom logs such as crystallinity value, energy consumption, total sugar yield after hydrolysis chemical compounds and molecular weight distribution after acid hydrolysis, were examined. In the results, crystallinity of waste mushroom logs which were three year passed after the inoculation was decreased drastically from 49% to 33% during the cultivation. Lignin contents as chemical compounds of normal woods and waste mushroom logs were 21.07% and 18.78%, respectively. By the results of measurement of energy consumption, the size reduction of normal woods required a significantly higher energy than that of waste mushroom logs. In the hydrolysis, total sugar yield by enzyme and acid hydrolysis were high in waste mushroom logs(53% 57.5%) than in normal woods(42.9%, 47.17%). According to the molecular weight distribution using GPC, low molecular weight compounds were distributed in waste mushroom logs. Based on these results, waste mushroom logs have enough potential as material for developing alternative energy because of easily conversion to sugar by various hydrolysis methods and requirement of low energy consumption during size reduction.

• Journal of Forest and Environmental Science
• /
• 제40권1호
• /
• pp.35-42
• /
• 2024

The Japanese larch (Larix kaempferi [Lamb.] Carriere) is a major timber species in Korea. However, studies on bucking rates and merchantable logs of this species are insufficient in South Korea. To bridge these gaps, in this study, the bucking rate of Japanese larch (Larix kaempferi [Lamb.] Carriere) was computed and the number of long logs and merchantable log volumes were analyzed. Sample trees were bucked according to the log grade for trading, and collected from a forest field in Gangwon Province. The bucking rate of all Japanese larch logs was >89%. The highly profitable 2-4 logs of 3.6 m length from trees with ≤30 cm diameter at breast height (DBH) and 5-6 logs with ≥34 cm DBH were produced. The bucking rate of long logs was >84%; thus, Japanese larch was found to be suitable for the supply of high-grade timber. Additionally, to follow reasonable wood supply plans, merchantable volume tables were offered based on 3.6 m-long number of logs and small-end diameter classes. Understanding the proportion of merchantable log volumes, bucking rates, and the number of long and short logs has large-scale applications in practical forestry.

• Journal of the Korean Wood Science and Technology
• /
• 제18권3호
• /
• pp.53-68
• /
• 1990

This research has been executed for maximization of lumber yield and more efficient use of small diameter logs. Sample logs from thinnings carne from densed artificial stands at the Kwangnung Experimental Forests situated in the central region of Korean peninsula. Species of sample logs were obtained to execute sawing and strength test for larch, and lumber strength test in full size for pitch pine and Korean pine. A survey on sawmills consuming domestic logs was carried out to know sawmill production, costs and utilization structure of lumber as a guide to business analysis. Results showed that sawing pattern from small logs less than 15cm in diameter was necessary to cut 9cm by 9cm square per one log in order to obtain high lumber recovery and provide for wide market needs. The total lumber yield of squares plus side boards was 56 percent to 58 percent from small logs and the yield for log sweep in 30 percent decreased by 24.5 percent in sawing production, compared to yield for straight logs. In sawing efficiency, production of lumber by twin band saw could be improved 238 percent higher than lumber of the same species produced by conventional sawmilling methods, and sawing accuracy with twin band saw was much higher at the lumber production than band saw. Lumber from the small larch logs has shown 70 knots per $m^2$ on its faces and also lumber showed lots of face checkings by air drying on the yard, compared to other species. MOR in bending of lumber in full size from small logs of larch was found ranging from 380kg/$cm^2$ to 460kg/$cm^2$, resulting in 40 percent less than the strength from clear small specimens. In lumber containing knots, cross grain, etc, longitudinal stress wave speed was delayed about 48 percent by defects in lumber from both larch and pitch pine logs. The surveyed sample sawmills consumed the domestic logs at the rate of 54 percent to 84 percent in the total timber consumption, showing high consumption at mills located in the mountains.

• Journal of Forest and Environmental Science
• /
• 제33권3호
• /
• pp.233-238
• /
• 2017

This study was carried out to figure out the number of logs for sawtimber by DBH and height class and to compare merchantable volume ratio by categorizing into sawtimber, lagging board and pulpwood, and others for Pinus densiflora, Pinus koraiensis, and Larix kaempferi. Logs for sawtimber were hardly produced in small DBH class of three species, but produced evidently from medium DBH class. In large DBH class, the number of logs for sawtimber were noticeably different among species: 4.3 logs for L. kaempferi, 2.6 logs for P. densiflora, and 1.0 logs for P. koraiensis on average. Similarly, merchantable volume ratio for sawtimber were largely different among species in large DBH class with higher than 15 m: 82% logs for L. kaempferi, 60% logs for P. densiflora, and 44% logs for P. koraiensis. When compared to the upper diameter and upper height by species with regard to the last log of a tree produced for sawtimber, upper diameter was smallest with 14.1 cm and upper height was highest with 12.2 m in L. kaempferi. Overall, L. kaempferi was considered as the more commercial species for sawtimber production than P. densiflora and P. koraiensis.

• 한국컴퓨터정보학회논문지
• /
• 제23권10호
• /
• pp.11-21
• /
• 2018

In this paper we propose a novel log template discovery algorithm which achieves high quality of discovered log templates through iterative log filtering technique. Log templates are the static string pattern of logs that are used to produce actual logs by inserting variable values during runtime. Identifying individual logs into their template category correctly enables us to conduct automated analysis using state-of-the-art machine learning techniques. Our technique looks at the group of logs column-wise and filters the logs that have the value of the highest proportion. We repeat this process per each column until we are left with highly homogeneous set of logs that most likely belong to the same log template category. Then, we determine which column is the static part and which is the variable part by vertically comparing all the logs in the group. This process repeats until we have discovered all the templates from given logs. Also, during this process we discover the custom patterns such as ID formats that are unique to the application. This information helps us quickly identify such strings in the logs as variable parts thereby further increasing the accuracy of the discovered log templates. Existing solutions suffer from log templates being too general or too specific because of the inability to detect custom patterns. Through extensive evaluations we have learned that our proposed method achieves 2 to 20 times better accuracy.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제17권2호
• /
• pp.486-503
• /
• 2023

Logs play an important role in mastering the health of the system, experienced operation and maintenance engineer can judge which part of the system has a problem by checking the logs. In recent years, many system architectures have changed from single application to distributed application, which leads to a very huge number of logs in the system and manually check the logs to find system errors impractically. To solve the above problems, we propose a method based on Message Middleware and ATT-GRU (Attention Gate Recurrent Unit) to detect the logs anomaly of distributed systems. The works of this paper mainly include two aspects: (1) We design a high-performance distributed logs collection architecture to complete the logs collection of the distributed system. (2)We improve the existing GRU by introducing the attention mechanism to weight the key parts of the logs sequence, which can improve the training efficiency and recognition accuracy of the model to a certain extent. The results of experiments show that our method has better superiority and reliability.

• 한국인터넷방송통신학회논문지
• /
• 제19권1호
• /
• pp.1-8
• /
• 2019

대량의 로그 자료로부터 가장 적합한 정보를 추출하기 위한 방법 중 귀납 추리를 이용한 방법이 있다. 본 논문에서는 디지털 포렌식 분석에서 침입 흔적 로그의 순위를 결정하기 위하여 귀납 추리를 이용한 방법 중 분류에 있어서 우수한 SVM(Support Vector Machine)을 이용한다. 이를 위하여, 훈련 로그 집합의 로그 데이터를 침입 흔적 로그와 정상 로그로 분류한다. 분류된 각 집합으로부터 연관 단어를 추출하여 연관 단어 사전을 생성하고, 생성된 사전을 기반으로 각 로그를 벡터로 표현한다. 다음으로, 벡터로 표현된 로그를 SVM을 이용하여 학습하고, 학습된 로그 집합을 기반으로 테스트 로그 집합을 정상 로그와 침입 흔적 로그로 분류한다. 최종적으로, 포렌식 분석가에게 침입 흔적 로그를 추천하기 위하여 침입 흔적 로그의 추천 순위를 결정한다.

• 한국산림과학회지
• /
• 제6권1호
• /
• pp.37-42
• /
• 1967

이 시험(試驗) 전남(全南) 광양연습림(光陽演習林)에 있는 약(約) 40여년생(餘年生)의 리기다소나무임분(林分)에서 하계벌(夏季伐)과 동계벌(冬季伐)을 실시(實施)한 다음 조재목(造材木)에 완전박피(完全剝皮), 외피박피(外皮剝皮)(내피부재(內皮付材)) 그리고 무박피처리(無剝皮處里)를 하여 이들이 천연건조(天然乾燥)에 미치는 박피처리(剝皮處理)의 효과(効果)를 구명(究明)하기 위(爲)하여 실시(實施)되었다. 이 시험(試驗)의 결과(結果)를 요약(要約)하면 다음과 같다. (1) 완전박피재(完全剝皮材)는 대체(大體)로 내피부재(內皮付材)나 무박피재(無剝皮材)에 비교(比較)하여 속(速)히 건조(乾燥)하나 건열피해(乾裂被害)를 많이 이르킨다. (2) 하계벌(夏季伐)을 실시(實施)한 완전박피재(完全剝皮材), 내피부재(內皮付材) 및 무박피재(無剝皮材)를 비교(比較)하면 완전박피재(完全剝皮材)와 내피부재(內皮付材) 및 무박피재간(無剝皮材間)에는 차이(差異)가 인정(認定)되어도 내피부재(內皮付材)와 무박피재간(無剝皮材間)에는 차이(差異)가 없다. (3) 동계벌(冬季伐)을 실시(實施)한 경우 내피부재(內皮付材)와 완전박피재간(完全剝皮材間)에는 차이(差異)가 없어도 완전박피재(完全剝皮材) 및 내피부재(內皮付材)와 무박피재간(無剝皮材間)에는 현저(顯著)한 차이(差異)가 있었다. 따라서 내피부재(內皮付材)의 건조효과(乾燥効果)는 완전박피재(完全剝皮材)의 효과(効果)와 같다고 생각(生覺)한다. (4) 이 시험(試驗)에서 하계벌(夏季伐)의 완전박피재(完全剝皮材) 그리고 동계벌(冬季伐)의 내피부재(內皮付材) 및 완전박피재(完全剝皮材)는 모두 4개월(個月) 이내(以內)에 평형함수량(平衡含水量)에 도달(到達)한다고 예상된다.

• 임산에너지
• /
• 제22권2호
• /
• pp.60-68
• /
• 2003

목재의 기계적 특성을 평가하기 위하여 여러 가지 비파괴 측정 기술이 도입되고 있다. 본 실험은 낙엽송(Larix kaempferi Carr.) 소경재 원목을 초음파의 통과 속도와 종진동의 고유진동수를 이용한 비파괴 측정 기술로 영계수를 측정하여 휨강도 실험을 통해 얻은 실측 영계수와 휨파괴계수의 상관관계를 검토하였다. 실험에는 50본의 소경재 원목이 사용되었다. 종진동의 고유진동수를 이용한 영계수와 실측 영계수는 비교적 높은 상관관계를 나타내었다. 초음파를 이용한 비파괴 영계수 측정은 옹이의 출현빈도가 높은 원목의 선별에 효과적이었으며 종진동의 고유진동수를 이용한 측정은 할렬의 출현빈도가 높은 원목의 선별에 효과적임을 확인하였다.

• Mycobiology
• /
• 제42권3호
• /
• pp.279-281
• /
• 2014

Severe bark decay disease was observed on oak logs at a shiitake cultivation farm in Geochang-gun, Gyeongnam province. The symptoms observed were fruiting bodies that had developed on the top and side surface of oak logs. As a result, the bark came off easily exposing the sapwood. Slime mold specimens collected from oak logs showed developing fruiting bodies comprising of stalks, hypothallus, capillitium, and columella, and the causal agent of bark decay disease was identified as Stemonitis splendens on the basis of morphological characteristics. To our knowledge, this is the first report of Stemonitis splendens causing bark decay of oak logs used for shiitake mushroom cultivation in Korea.