• Communications for Statistical Applications and Methods
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• v.15 no.3
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• pp.451-464
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• 2008

Six sigma is the rating that signifies "best in clas", with only 3.4 defects per million units or operations. Higher sigma quality level is generally perceived by customers as improved performance by assigning a correspondingly higher satisfaction score. The process capability indices and the sigma level $Z_{st}$ have been widely used in six sigma industries to assess process performance. Most evaluations on process capability indices focus on point estimates, which may result in unreliable assessments of process performance. In this paper, we consider statistical inference for process capability indices $C_p$, $C_{pk}$ and $C_{pm}$. Also, we study better testing procedure on assessing sigma level $Z_{st}$ and capability index $C_{pm}$, for practitioners to use in determining whether a given process is capable. The proposed method is easy to use and the decision making is more reliable. Whether a process is clearly normal or nonnormal, our bootstrap testing procedure could be applied effectively without the complexity of calculation. A numerical result based on our proposed method is illustrated.

• Journal of Korea Water Resources Association
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• v.46 no.5
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• pp.519-530
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• 2013

To provide a reliable tool for runoff simulations of ungauged watersheds upstream of reservoirs, a daily runoff simulation model, Tank model, is restructured, the parameter regionalization of the model is conducted, and the model's applicability is evaluated. Taking into account the characteristics of runoffs from the watersheds, a three-tank model is employed. The percolation process of the model's third tank is eliminated, considering the water budgets of the watersheds, and its evapotranspiration component is improved, reflecting the conditions of meteorological observation in South Korea. The sensitivity analysis of the model shows that the model's behaviors, varying with a sensitive parameter, ${\alpha}$, are reasonable. The regional parameter estimation equations are determined, using the characteristics and land uses of the watersheds as variables. The model is applied for the runoff simulations of three watersheds and the water stage simulation of one reservoir, and the simulation results are then compared with the observed values, which prove to be in close agreement with the observations. In addition, the results from simulating inflows of twenty-four reservoirs using the model show that the averages of evapotranspiration rate and runoff rate are 42.8% and 56.6%, respectively, which are resonable. Consequently, it is concluded that the model is practically applicable to simulating runoffs from watersheds upstream of reservoirs, and simulated inflow data are useful for watershed management and reservoir planning, design, and operation.

• Journal of Wetlands Research
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• v.17 no.2
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• pp.163-175
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• 2015

In this paper, soil erosion and soil loss management system (SMS) of the City of Calgary in Albert, Canada was reviewed. Regulatory basis supporting this soil management system, permit process and conditions, guidelines and principles for the SMS, and monitoring and repair duties, inspection were discussed. Permit process in the City of Calgary is handled mainly by Urban Development Division, in which special task force called CPAG (Coorporative Planning Application Group) (if necessary circulated through related subdivisions). Inspects all the permit conditions and decides permit or refusal, and LUM (Land Use and Mobility) advertises the approval, if there is no appeals, permit is released to developers. If permit is rejected, applicant can appeals Development Appeal Board, it can approve or reject. In addition to permit, the city has manual for soil management plan, which includes BMP selection, design, monitoring, maintenance, and inspection activities. Perfect SMS policy does not necessarily guarantee relieving the soil-particle related pollution problem, but in Korea, we have to recognize that construction works during development is potentially the most destructive stage of environmental pollution. The central and local governments must make preparations for the effective and tight regulations and ordinance which is appropriate for regional social-economic conditions.

• Journal of Wetlands Research
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• v.20 no.3
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• pp.256-262
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• 2018

Multiple temporal scale can be a useful method to understand population dynamics in ecosystem. The multi-temporal scale approach for population dynamics has rarely been researched till lately. This study was carried out to identify the factors in affecting the population dynamics of herons, including Eastern Cattle Egret (Bubulcus coromadus), Grey Heron (Ardea cinerea), Great Egret (A. alba), Intermediate Egret (Egretta intermedia) and Little Egret (E. garzetta), at rice paddy fields of Seokmun-myeon in the city of Dangjin, South Chungcheong Province during the main breeding periods from 2014 to 2017. We identified the population dynamics of herons at different time interval (day and month) using the unmanned monitoring system. As a result, monthly population dynamics was mostly affected by time, mean temperature and mean precipitation, whereas daily population dynamics was affected by mean temperature and habitat types. The results suggest that there are differences in the factors affecting the population dynamics of herons according to the time scale.

• Korean Journal of Food Science and Technology
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• v.42 no.2
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• pp.147-154
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• 2010

Gulbi, made of fresh yellow corvenia (Psendosciaena manchurica) that has been salted and dried, is one of the most popular traditional marine foods in Korea. The objective of this study was to develop a method to safely manufacture Gulbi with low levels of oxidation and contamination, by a hot air drying method. Changes in total acidity, pH, salt concentration, thiobarbituric acid-reactive substance (TBARS) and volatile basic nitrogen (VBN) were measured during drying at 30, 35 and $40^{\circ}C$ for 15 days in a hot air-dryer using a semi-dried method. Acidity increased with increasing drying time at all drying temperatures. The pH decreased gradually with increasing drying time. Salt concentration was increased as drying time increased at all drying temperatures due to moisture loss. The VBN increased as drying time increased for all drying temperatures. Data indicate that the drying at $35^{\circ}C$ appears to have a significant sensory and physicochemical advantage in Gulbi products.

• Journal of Korean Society of Forest Science
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• v.78 no.4
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• pp.381-395
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• 1989

The main purpose of this research is to provide scientific informations about standard wage and performance tariffs in forest management with special reference to working time for thinning. To identify relationships between net working time and tree characteristics, three geographically different sample plots were established at Yangsan, Bongpyung and Jinan and 460 oaks, 372 Japanese larches, 232 red pine and 240 pitch pine mere selected at each sample plots. The results of statistical analysis using multiple regression are as follows ; 1. Five independent variables of breast height diameter(DBH), mid-diameter(MD) large end diameter(LD), log-length(L), No. of branches(NOB) were stable independent of worker and tree species. 2. Comparing correlation coefficient of five independent variables, the best predictive variables, breast height diameter and No. of branches, were selected. Breast height diameter and No. of branches were identified as the most important independent variables in terms of effect on the dependent variable of the working time. 3. Comparing coefficient of determination (Rp) and residual mean square (MSEp), the best Linear regression equation for each tree species was selected as follower : $WT=a+b1{\times}NOB+b2{\times}DBF$ 4. Proportion of hang-up time to total working time in thinning were 66% in oak stand, 74%, in Japanese larch stand, 55%, in red pine stand and 52% in pitch pine stand, respectively. 5. Based on the best regression equation, a table of working time was made by strata of number of branches and breast height diameter. 6. Total working time using the best regression equation in Table 5 can be predicted in terms of felling time, limbing time, hang-up time, i.e., total working time increases by 11 to 13 seconds with every 1 centimeter increase in breast height diameter from 7 to 16 centimeter.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.10
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• pp.1723-1730
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• 2008

The national IT outsourcing is actively achieved centering around the manufacturing enterprise and financial institution. The If outsourcing of the public institution is generalized. The IT development and operation management task are the field in which first an outsourcing is introduced due to a factor including the technological change, the efper increase in demand, and etc. Particularly, the core business of the public institution is the public service. Therefore, the core business of the public institution can concentrate on the core business and by drastically outsourcing the etc task ran improve an efficiency. Therefore, as to the IT outsourcing, the innovative method that can enhance the quality of the public service can become. In this paper, We analyze how the Supply Administration introducing the service level agreement (SLA: Service Level Agreement) and the problem that the Samsung SDS is faced with were solved. And the practical affairs guide-line for managing elements which can minimize trial and error and successfully implement the IT outsourcing is presented.

• Journal of The Geomorphological Association of Korea
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• v.19 no.1
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• pp.99-108
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• 2012

To consider geomorphological and geological characteristics to Gatbawi(the 500th natural monument), it was investigated with the aspect of scale, form, mineralogy, chemistry and weathered state. Showing typically erosional features, micro-terrains as sea cliffs, sea notches, marine plateaus and tafoni developed well on coastal areas near the monument. Sea cliffs are vertical and form sea notches in their bases. Coastal terraces are 3.5m in width and 20m in trace. Tafoni are honey combed. The monument is mainly composed of quartz, plagioclase, microcline, biotite, sericite in mineral and corresponded to crystalline tuff dominated in quartz and plagioclase. It has 23.60~28.27 wt.% of $Al_2O_3$, 3.27~5.80 wt.% of $Na_2O$, and 0.11~0.20 wt.% of Cl in chemical contents, leveling higher than those of earth crust standards. It is considerably weathered on the basis of CAI(77.42~83.93%). The monument is very useful for natural perspective tourism and education. Therefore, it is necessary that several ideas as guide plates, observing telescope, explaining guider, education programs connected with related services, touring goods, picture for books on utilization on the monument must establish.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.40-40
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• 2019

시민인식은 하천관리를 포함한 공공정책 수립에 결정적 요소들 중 하나로 강조되고 있다. 따라서 하천관리체계의 변화에 따른 사회적 하천관리에 미치는 영향을 파악하고, 특히 우리나라 물관리 일원화 후 하천의 이용과 관리 및 정책에 대한 시민 인식을 조사하는 것은 향후 하천 정책 수립에 매우 중요하다. 본 연구의 목적은 하천의 이용, 관리(주체), 정책, 기후변화 등에 대한 시민의 관심도와 만족도를 조사하는 것이다. 이번 설문 대상은 전국의 남녀 4,500명(10대~60대)이었으며 패널 참여 방식으로 조사되었다. 설문 문항의 구성은 크게 하천 이용, 하천 관리, 그리고 물관리 일원화와 기후변화 등을 포함한 하천정책 등으로 3대 주제로 세부 문항들이 개발되었다. 설문조사의 주요 결과는 조사대상 시민들의 약 22.9%는 매주 하천을 방문하는 것으로 분석되었으며, 1년간 1번은 하천을 방문(이용)하는 시민들은 85.5%로 나타났다. 자주 방문하는 하천의 규모 혹은 위치는 중(中)하천이 42.2%로 가장 높았고, 대(大)하천은 23.9%, 소(小)하천은 17.5%, 도랑이나 개울은 15.5%로 나타났다. 기타(0.9%)로는 하천 외에도 물을 접할 수 있는 저수지, 인공하천 및 호수공원 등을 이용하는 것으로 나타났다. 하천 방문자 중 최소 2시간을 체류하는 시민 중 약 96.4%는 걸어서 하천을 접근하고, 지하철을 이용하여 하천을 접근하는 방문자는 최소 1시간에서 2시간 이상을 체류하는 것으로 조사되었다. 조사대상 시민들은 하천관리 중에서 접근 편의성(28.4%), 친수시설(자전거 도로, 산책로 등) 관리(24.2%), 수질관리(9.9%)로 만족하는 것으로 나타났다. 반면에 수질(27.4%, WQ(water quality))과 냄새 및 쓰레기(25.5%, OW(odor and waste))가 가장 높게 하천관리의 불만족도를 가지고 있었다. 기후변화 영향에 대한 시민들의 관심도는 WQ (29.6 %), OW (17.7%), 그리고 물부족 (15.1%)의 순서로 조사되었다. 하천의 바람직한 미래상에 대한 관심도는 깨끗한 수질의 하천(36.1%, WQ), 휴식과 산책을 즐길 수 있는 하천(22.9%), 다양한 동 식물의 생태서식공간(14.6%)의 순으로 나타났다. 또한 시민들은 하천관리 기관의 가져야할 역량은 '전문성'이 가장 중요하게 인식하고 있는 것으로 조사되었다. 우리나라 물관리 정책 중 가장 큰 문제로 우선순위 1~3순위 누적 조사 결과, 수질악화(79.9%, WQ), 하천 수생물 훼손(49.6%), 정부부처 간 협력부족(37.6%)으로 인식하는 것으로 나타났다. 끝으로 2018년 추진된 물관리 일원화 후 정부의 물관리 및 하천 정책에 대한 시민들의 관심도는 WQ (46.0%), 물공급 관리 (17.6%), 그리고 생태계 복원 (8.4%)의 순서로 조사되었다. 본 연구의 결론들 중 하나는 현재와 미래 하천에 대한 가장 높은 시민들의 수요는 깨끗한 수질과 생태서식공간이었으며 이는 향후 하천 정책 수립에 있어서 중요한 기초가 될 것으로 전망된다.

• Journal of Aerospace System Engineering
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• v.12 no.1
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• pp.10-16
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• 2018

In 2018 and 2019, GEO-KOMPSAT-2A and GEO-KOMPSAT-2B will be launched in order to succeed the COMS mission. The two satellites will be collocated in $128.25{\pm}0.05$ degrees East. For precise ranging and orbit determination, the GEO-KOMPSAT-2B will be equipped with LRA (Laser Retroreflector Assembly) and SLR (Satellite Laser Ranging) systems will be utilized. This systems are located in Geochang. In this case, the laser beam emitted from the SLR station can cause problems in terms of safety of optical payloads and image quality. As a solution of this possibility, the laser ranging will be done during the night time when the shutters of the optical payloads remain closed. Still, the optical payload of the GEO-KOMPSAT-2A is not safe from the laser beam because its optical payload shall continue its mission for 24 hours a day. In order to handle this problem, the laser ranging shall be limited to time slots when the angular distance between two satellites observed from the Geochang SLR station is large enough. In this paper, through orbit simulations, the characteristics of variation of the angular distance between the two satellites is analyzed to figure out the time slots when laser ranging is allowed.