• Nuclear Engineering and Technology
• /
• 제27권1호
• /
• pp.8-17
• /
• 1995

최근 디지탈 기술을 응용하여 원자력 발전소 제어 시스템의 성능을 향상시키려는 많은 노력이 있어 왔고, 차세대 원자로에 구현할 것을 목표로 디지탈 제어 시스템 개발에 관한 장기적인 계획이 수립되어 있다. 디지탈 제어 시스템을 구축하고자 할 때 적정한 샘플링 주기를 정하는 것은 중요한 과정이다. 제어기의 안정성과 성능은 샘플링 주기에 밀접한 관련이 있다 현재 디지탈 제어기의 샘플링 주기를 체계적으로 정하는 전형적인 방법은 없다. 일반적으로 디지탈 제어기의 안정성을 고려해서 연속시간역 제어의 대역폭의 20∼30배의 역수 정도의 샘플링 주기를 흔히 쓴다. 이 논문에서는 안정성 뿐 아니라 시간역에서의 좋은 성능을 보장받을 수 있는 적정한 샘플링 주기를 얻을 수 있는 방법을 제시하였다. 이 방법으로 Irving의 모델을 이용하여 디지탈제어기의 적정 샘플링 주기를 예측하고, 고리 2호기의 마이크로 시뮬레이터와 WDPF 디지탈 제어기를 이용한 증기 발생기 수위제어 모사시스템에서 검증해 본 결과, 고리 2호기 원자력발전소 중기 발생기 수위제어를 위한 디지탈 제어기의 원자로 전 출력영역에 대한 적정 샘플링 주기 가 1초가 되는 것을 알게 되었다.

• 대한수의학회지
• /
• 제47권4호
• /
• pp.417-423
• /
• 2007

Serological surveillance programs in animal populations are becoming increasingly important to estimate prevalence of a specific disease and subsequently to document disease-free status in a region or a country. For these purposes, the programs need to be based on both theoretical and economical aspects from the designing phase. From Aujeszky's disease (AD)-eradication program point of view, group of animals (aggregates, herds) not individual animal is the more important sampling unit of concern. In this study the authors therefore attempted to compute an appropriate sample size tailored to a current surveillance program against AD, assuming that the goal of this program is either herd-level prevalence estimation or documentation of AD-freedom. For prevalence estimation, assuming a finite population with imperfect sensitivity (Se) and specificity (Sp) of ELISA kit for AD diagnosis, the number of herds present, expected herd prevalence, and desired accuracy for a certain level of confidence, sample size was estimated at herd-level in the first stage and individual animal-level in the second stage. A two-stage sampling design was used to calculate a sample size to indicate AD-freedom. In this instance, the computation was based on the possible detection of a predetermined prevalence at a certain herd-level Se and Sp. This study indicated that the sample size varied with predetermined confidence, tolerance, Se and Sp at herd- and animal-level, and within- and among-herd prevalence. In general, smaller sample size was required to estimate AD prevalence than to document of AD-freedom. Compared to individual-based samples, two-stage sampling strategy requires a larger sample size to show disease-freedom. Statistical considerations including herd-level test characteristics when designing surveillance program also are further discussed.

• Journal of Forest and Environmental Science
• /
• 제35권3호
• /
• pp.205-211
• /
• 2019

The objective of this research was to assess the amount of carbon stock of coarse woody debris (CWD) in Bombo-Lumene Reserve. Data on lying CWD was collected on 35 circular sampling plots using Line Intersect Sampling (LIS) method. A total of 230 samples CWD (${\geq}10cm$ diameter) were inventoried. The mean carbon stocks of CWD was $29.48Mg\;C\;ha^{-1}$, ranging from 4.32 to $73.54Mg\;C\;ha^{-1}$. The CWD carbon stocks displayed a wide range of variation in decay states. The allocation of CWD among the decay class of all the CWD samples reveals that the most important classes were class 1 and class 3 with 323.66 and $321.96Mg\;C\;ha^{-1}$, followed by class 4 with 264.56 and the last one was class 2 with $121.72Mg\;C\;ha^{-1}$. The results suggested that the dead wood component is important in carbon sequestration and should be taken into consideration for quantification of carbon stocks not only in Bombo-Lumene Reserve, but in all forest ecosystems in the Democratic Republic of Congo.

• 정보보호학회논문지
• /
• 제21권1호
• /
• pp.125-133
• /
• 2011

최근 들어, 모바일 단말의 폭발적인 보급 더불어 단말 내의 중요정보가 외부 저장 매체로 불법적으로 유출되는 보안 위협이 증가되고 있다. 따라서, 본 논문에서는 단말 내 중요정보의 외부 저장 매체로의 유출 방지 기법을 설계 및 구현한다. 이 기법은 파일의 임의위치에서 시그니처를 샘플링하고 이를 이용하여 유출 탐지, 차단 기능을 수행한다. 시그니처 샘플링 과정은 대상 파일을 일정 크기의 추출 윈도우로 구분한 후 이 영역 내에서 임의의 위치에서 1개 이상의 시그니처를 추출한다. 그리고, 가장 효과적인 샘플링을 수행하기 위하여 전체 샘플링, 이항분포 샘플링, 동적 샘플링의 다양한 추출 방식을 구현 및 시뮬레이션을 수행 한다. 제안된 기법은 파일의 임의 위치에서 시그니처를 샘플링하여 공격자의 시그니처 예측성을 낮출 수 있고 원본 데이터에 대한 변형 없이 유출 방지기능을 효과적으로 구현할 수 있다는 장점을 가진다. 따라서, 사용자 편의성이 중시되고 비교적 저 사양의 시스템인 모바일 단말에서 효과적으로 유출방지 기능을 구현할 수 있는 기법이다.

• Nuclear Engineering and Technology
• /
• 제35권5호
• /
• pp.387-398
• /
• 2003

For reference human intrusion scenarios constructed in previous study, a probabilistic safety assessment to derive the radionuclide concentration limits for the low- and intermediate- level radioactive waste disposal facility is conducted. Statistical approach by the Latin Hypercube Sampling method is introduced and new assumptions about the disposal facility system are examined and discussed. In our previous study of deterministic approach, the post construction scenarios appeared as most limiting scenario to derive the radionuclide concentration limits. Whereas, in this statistical approach, the post drilling and the post construction scenarios are mutually competing for the scenario selection according to which radionuclides are more important in safety assessment context. Introduction of new assumption shows that the post drilling scenario can play an important role as the limiting scenario instead of the post-construction scenario. When we compare the concentration limits between the previous and this study, concentrations of radionuclides such as Nb-94, Cs-137 and alpha-emitting radionuclides show elevated values than the case of the previous study. Remaining radionuclides such as Sr-90, Tc-99 I-129, Ni-59 and Ni-63 show lower values than the case of the previous study.

• 대한약침학회지
• /
• 제15권3호
• /
• pp.7-12
• /
• 2012

Objective: This study aimed to summarize and analyze the usage of and the satisfaction levels with combined treatment including Oriental and Western medicine. Methods: We searched studies on the usage of and the satisfaction levels with combined treatment including Oriental and Western medicine over the past 10 yrs (2001-2011) from 3 Korean databases (National Assembly Library, Research Information Service System, and National Discovery for Science Leaders). The reviewers also conducted a summarizing analysis by sampling the literature according to the type of study, study period, region, study subjects, sample size, type of sampling, research method, data analysis, study instruments, main results, etc. Results: When the main results of six studies on combined treatment usage and satisfaction levels were considered together, the most important decisive factor in determining the usage of combined treatment was the illness of the patient, followed by the patient's occupation, sex, age, education, marital status, religion, treatment cost, and treatment results. In addition, the most important factor that determined satisfaction levels with combined treatment was age, followed by education, religion, income, health status, treatment procedures, staff attitude, and cleanliness. Conclusions: Elderly patients with musculoskeletal, cerebro-vascular, and circulatory system illnesses are more likely to prefer combined treatment over independent Oriental or Western treatment and are more likely to request specialized, adjusted medical care.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제12권10호
• /
• pp.5143-5158
• /
• 2018

Improving the intrusion detection system (IDS) is a pressing need for cyber security world. With the growth of computer networks, there are constantly daily new attacks. Machine Learning (ML) is one of the most important fields which have great contribution to address the intrusion detection issues. One of these issues relates to the imbalance of the diverse classes of network traffic. Accuracy paradox is a result of training ML algorithm with imbalanced classes. Most of the previous efforts concern improving the overall accuracy of these models which is truly important. However, even they improved the total accuracy of the system; it fell in the accuracy paradox. The seriousness of the threat caused by the minor classes and the pitfalls of the previous efforts to address this issue is the motive for this work. In this paper, we consolidated stratified sampling, cost function and weighted Support Vector Machine (WSVM) method to address the accuracy paradox of ID problem. This model achieved good results of total accuracy and superior results in the small classes like the User-To-Remote and Remote-To-Local attacks using the improved version of the benchmark dataset KDDCup99 which is called NSL-KDD.

• 가족자원경영과 정책
• /
• 제4권1호
• /
• pp.95-111
• /
• 2000

The family financial management is the important element which has a effect on the improvement of family economic well-being. Thus the study sets up human & material resources and requirement as an input factor, family financial management as an throughput factor, and economic well-being as an output factor, and then identifies if there are some relationships among them by using a systematic approach of family financial management. The questionaires were distributed to 600 employed wives by carrying out cluster sampling and disproportional stratified sampling. The 573 cases of them were used as the mean, ratio, Pearson’s Correration, ANOVA, factors analysis, and Stepwise Regression using the SAS/PC+. The major findings of the study are as follows: 1) A practical application of information as on input variable, appears the fator which has an important effect upon the throughput factor, that is, family financial management. The employed wives should manage a lot of resources in rapidly changing social-economic circustances. So it shows that not only they should take informations open to their daily life and then make practical use of them in managing their family finance, but also they must be capable of judging and accepting reasonable informations in order to gain and manage resources suitable to the characteristics of family finance and family members’need. 2) There was significant relationship between the employed wives’family financial management and family economic well-being, focused on the systematic theory of family financial management. This study provides for the information to develope the program for the employed wives’family financial planning and counseling.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권10호
• /
• pp.999-1006
• /
• 2020

This study provides an understanding of the role of job satisfaction as a mediator of compensation and workplace environments for the organizational commitment of employees in the public sector. This study used a structural model using path analysis. The population and sample in this study were all employees at the Population and Civil Registry Office of one of the districts in Indonesia. The sampling technique used was total sampling, due to the considerably smaller amount of the sample size. This study found that compensation and workplace environment could explain job satisfaction variables with a 93.8% confidence level and simultaneously compensation, workplace environment, and job satisfaction that could explain organizational commitment with a variable of 97.4%. This findings also shows that the manifest bonus variable on the latent compensation variable is one of the main indicators that needs to improve to increase job satisfaction and organizational commitment. One of the important things which needs to be done is to increase compensation. The first thing which needs to be done is to increase the bonus. Furthermore, to improve the quality of the workplace environment, facilities, and infrastructure such as stable internet connections, computer specifications are the important criteria that must be met.

• 한국기계기술학회지
• /
• 제13권2호
• /
• pp.45-54
• /
• 2011

A vehicle suspension system performs two functions, the ride quality and the stability, which conflict with each other. Among the various suspension systems, an active suspension system has an external energy source, from which energy is always supplied to the system for continuous control of vehicle motion. In the process of the linearization for the nonlinear active suspension system, the frequency dependent damping method is used for the exact modelling to the real model. The pressure control valve which is controlled by proportional solenoid is the most important component in the active suspension system. The pressure control valve has the dynamic characteristics with 1st order delay. Therefore, It's necessary to adopt the lead compensator to compensate the dynamics of the pressure control valve. The sampling time is also important factor for the control performances. The sampling time value is proposed to satisfy the system performances. After the modelling and simulation for the pressure control valve and vehicle dynamic, the performances of the vehicle ride quality and the stability are enhanced.