• Nutritional Sciences
• /
• 제7권2호
• /
• pp.92-97
• /
• 2004

Despite the universal recommendation to eat a variety of foods, we still do not know whether and to what extent the variety affects dietary quality. This study was performed to evaluate the dietary variety scores as tools for assessing the dietary quality of Korean young adults. The 1-day dietary intake data were collected from 144 male and 214 female college students (>18 years) using the 24-hour recall method Relative nutrient intake compared to Korean Recommended Dietary Allowance (KRDA) as the nutrient adequacy ratio (NAR), were computed Also, the mean adequacy ratio (MAR) was calculated. Dietary variety score (DVS) was determined by counting the number of food items consumed daily, and the dietary diversity score (DDS) by counting the number of food groups consumed daily. Results showed that DVS, DDS and MAR were significantly correlated to each other. The MAR score significantly increased as DDS increased in both men and women. When different DVS (20$\leqDVS\leq$ 30) was evaluated for its sensitivity, specificity, measured prevalence, true prevalence, and positive and negative predictive values towards MAR, DVS 21 was revealed to be optimal dietary variety score as a cutoff point to differentiate Korean young adults with or without an adequate and balanced diet. Nutrient intakes of subjects who had DVS<21 were significantly lower than those of subjects with DVS$\qeq$ 21. These results indicate that the dietary variety score appeared to be an effective tool for evaluating the adequacy of diet in Korean young adults.

• 한국산림과학회지
• /
• 제95권1호
• /
• pp.12-22
• /
• 2006

자기안내식 해설판의 정보전달 효과를 높이기 위해서는 해설판 글자의 가독성에 대한 이해가 필요하다. 본 연구에서는 해설판의 글자속성에 따른 가독성을 각각 비교하였다. 2004년도 9-11월중 무등산도립공원 내 너덜겅 지역에서 총 1391명의 응답자를 대상으로 설문조사를 실시하였다. 본 연구에서 선정된 5개 글자속성(글자체, 글자정렬, 글줄간격, 글자간격, 한 줄의 글자수)의 가독성 비교 결과, 글자크기 58포인트의 경우 글자체는 'Hy 견명조', 글자정렬은 '양단정렬', 글줄간격은 190%(한글 2002), 글자간격은 10(한글 2002), 한 줄의 글자수는 25자일 때 각 글자속성의 가독성이 최적으로 나타났다. 최적 가독성으로 나타난 각각의 글자속성을 조합하여 제작한 해설판의 글자를 예시하였으며, 가독성과 관련하여 해설판 글자디자인과 추후 연구 문제에 대하여 토의하였다.

• 한국임상수의학회지
• /
• 제29권1호
• /
• pp.58-62
• /
• 2012

To protect aquatic animal health of importing countries from the potential risks associated with exotic diseases introduced through international trade of live aquatic animals, inspection of designated commodities at ports of entry is a critical component of the safeguarding system. The only way to be 100% confident that no fishes in a shipment are infected with a specific agent is to test every fish in the commodity imported with a perfect diagnostic test. For the majority of cases, this is unrealistic since the group of interest may very large particularly for aquatic animals, or imperfect tests are often available. It is, therefore, more common to test a fixed proportion of a group by preplanned sampling schemes. However, decision making based on results of testing the sample can provide quite a chance that infected groups may be misclassified as uninfected, depending on sampling strategy employed. The objective of this study was to determine the possibility that one or more fishes in the group imported being infected but tests negative after inspecting samples. This question is critical to government authorities to examine whether sampling plan is sufficient to achieve the purpose intended for. At fixed population size, the maximum number of infected fishes when all tests negative was decreased as the sampling fraction increased. The probability of including at least one undetected but infected fish in a group for negative tests increased with the number of fish tested or true prevalence. The risk was much lesser where high sensitivity test was assumed; when increasing test sensitivity from 0.9 to 0.99, this risk was dramatically reduced to about a tenth or a fourth for prevalence ranges from 2 to 10%, given sample size ranges from 10 to 200. Based on the preliminary analysis, the author concluded that current sampling plan testing 4-8% of the import proposal for human consumption still can yield high false negative results. Therefore, from the quarantine inspection point of view, an enforced commodity-specific sampling design that accounts for the cost of testing with an imperfect test at the specified design prevalence is urgent.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 1999년도 추계학술대회 논문집
• /
• pp.46-53
• /
• 1999

As of July 1999, i,185 lomocotives(excluding metropolitan area electric locomotives) are in Korean National Railroad(KNR). With this limited number of resources assigning locomotives to each trains of timetable is very important in the entire railway management point of view because schedule can be regarded as goods in transportation industry. On a simple rail network, it is rather easier to assign proper locomotives to trains with the experience of operating experts and get optimal assignment solution. However, as the network is getting bigger and complicated, the number of trains and corresponding locomotives will be dramatically increased to rover all the demands required to service all of the trains in timetable. There will be also numerous operational constraints to be considered. Assigning proper locomotives to trains and building optimal cyclic rotations of locomotive routings will result in increasing efficiency of schedule and giving a guarantee of more profit. The purpose of this study is two fold: (1) we consider a planning-level locomotive scheduling problem with the objective of minimizing the wasting cost under various practical constraints and (2) development of implementation prototype program of its assigning result. Not like other countries, i.e. Canada, Sweden, Korean railroad operates on n daily schedule basis. The objective is to find optimal assignment of locomotives of different types to each trains, which minimize the wasting cost. This problem is defined on a planning stage and therefore, does not consider operational constraints such as maintenance and emergency cases. Due to the large scale of the problem size and complexity, we approach with heuristic methods and column generation to find optimal solution. The locomotive scheduling prototype consists of several modules including database, optimization engine and diagram generator. The optimization engine solves MIP model and provides an optimal locomotive schedule using specified optimization algorithms. A cyclic locomotive route diagram can be generated using this optimal schedule through the diagram generator.

• Journal of Ecology and Environment
• /
• 제43권3호
• /
• pp.320-331
• /
• 2019

Background: Dioecious plant species having both male and female plants have been investigated regarding sex-related characteristics such as sex ratio, sex-differential resource requirements, and spatial segregation of the sexes. Habitat loss and fragmentation are major threats to the survival of plant populations, but dioecious species are particularly more prone to such habitat degradation than non-dioecious species because of their dimorphic sexual system. We examined the sex-related demographics of two Ilex cornuta populations being different regarding land use history. Methods: During 2016-2017, we examined I. cornuta trees with a basal diameter ${\geq}1.5cm$ in the Yongsu-ri population (YS population) and the Gotjawal Provincial Park population (GP population). Plant sex (male, female, or unsexed) was identified. The tree size (basal diameter and height of the main stem), clonal production (the ramet numbers per genet), and vitality for each clone were measured. The associations between population, sex, tree size, clonal production, and vitality were examined using ANOVAs and contingency table analyses. Finally, point pattern analyses using O-ring statistics were conducted to assess spatial patterns. Results: Upon excluding unsexed trees, the YS population with 74 trees was significantly male-biased (0.66), while the GP population with only 26 trees had a 1:1 sex ratio. In both populations, males and females did not differ in tree size. Although the mean number of ramets differed significantly between populations, females tended to produce more ramets than males. The proportion of weak trees was significantly higher in the YS than in the GP population. Neither population showed evidence of spatial segregation of the sexes. Conclusions: The two populations of dioecious I. cornuta are characterized by the small number of trees and relatively high frequencies of non-reproductive trees. Both indicate that these populations are quite susceptible to environmental and genetic stochasticity. On the other hand, the differences between populations in sex ratio, clonal production, and vitality suggest that conservation efforts for I. cornuta need to be population-specific. In order to help recover and enable this vulnerable species to persist, it is necessary to find ways to enhance their sexual reproduction and simultaneously reduce habitat disturbances due to anthropogenic activities.

• 아태비즈니스연구
• /
• 제11권3호
• /
• pp.229-242
• /
• 2020

Purpose - To study the factors that are related with compliance for the voluntary surrender program of drive's license for senior drives and to estimate the rate of voluntary surrender. Design/methodology/approach - We online surveyed 147 individuals in order to analyze the intention to comply the program. The surveyees were driver's license holders aged 54 to 65 and drawn to answer their willingness to comply in a 5-point Likert scale. We developed an ordered probit model to analyze the data. Findings - According to the main results of the empirical analysis, the higher the average number of driving per week, regardless of gender and age, the more negative was the driver toward voluntarily surrender of driver's license. Various policy measures need to be prepared to activate the voluntary surrender system using the willingness to voluntarily surrender the driver's license and the characteristics of the voluntary returners, and the implementation of customized safe driving training for elderly drivers may be one such method. Research implications or originality - Population aging is known to cause various social problems, and in the transportation field, the number of elderly drivers and traffic accidents by elderly drivers are also increasing. The government is implementing a program for elderly drivers to voluntarily surrender of their driver's licenses in order to reduce traffic accidents caused by elderly drivers. If only elderly drivers who rarely drive surrender their driver's licenses then traffic accidents may not reduce as much as the program targets, however, and further policy instruments may be needed.

• Journal of the Korean Wood Science and Technology
• /
• 제49권2호
• /
• pp.122-133
• /
• 2021

The radon gas from nature mainly considers a cause of radon problems, and it is closely affect human life cycle. Korean yellow residual soil, Hwangtoh, widely used as a building material, is considered to be one of major sources of indoor radon. However, there have, as yet, been no studies about radon from Hwangtoh in mass market brands. Here, we investigated the indoor radon concentrations and exhalation rates in four Hwangtohs from different brand names and regional features. The Closed Chamber Method (CCM) conducted by a Continuous Radon Monitor (CRM) has been used for the rates of radon exhalation. Based on equations of previous references, the indoor radon concentrations were deducted. As a result, the radon surface exhalation rates resulted in the 1.4208 to 3.0293 Bq·㎡·h-1 range. Significant differences were found among Hwangtohs according to production regions. Materials with higher radon concentration required a longer time to reach a quasi-steady state in a given environment, in other words, the number of half-life cycles increased from a set starting point. The experimentally identified Hwangtohs demonstrated its safety for construction purposes. There exists, so far, a possibility to exert influence radon emanation due to unidentified factors. Therefore, it is necessary to corroborate with more research by increasing the number of Hwangtohs, considering the other references reported high radon exhalation rates. In addition, it is highly recommended that the radon exhalation rates should be measured for all building materials for preventing human health before the material usage.

• 실천공학교육논문지
• /
• 제13권3호
• /
• pp.507-514
• /
• 2021

본 연구에서는 K대학교 공과대학에서 학위 연계형 일학습병행제 학습근로자들에게 최초로 학위를 수여한 2020년 2월 졸업자를 대상으로 이루어진 조별 졸업 작품 제작과 그 결과를 공학 논문 체계로 완성하는 단계까지 진행한 과정을 제시하고, 대상자들에게서 얻어진 39개 항목의 설문조사 결과를 같은 학년도 졸업자인 같은 전공의 전일제 학생들의 결과들과 비교 분석하였다. 5개 대표 응답 문항을 집단별로 구분하여 통계 분석을 시도하였으나, 각 집단별 인원이 30명 미만으로 응답 결과의 정규성 검정 및 모수적 방법에 의한 통계 분석이 제한되었다. 그러나 가능한 일표본 t-검정을 중심으로 작품 주제 변경 횟수와 조원간 만족도, 작품 지도에 관련된 응답 항목에서 5점 척도 기준 집단간 평균 0.8점 이상 차이가 남을 확인하였고, 이에 대한 대처 방안을 제시하였다.

• International Journal of Internet, Broadcasting and Communication
• /
• 제16권1호
• /
• pp.17-28
• /
• 2024

As listed as one of the most important requirements for Post-Quantum Cryptography standardization process by National Institute of Standards and Technology, the resistance to various side-channel attacks is considered very critical in deploying cryptosystems in practice. In fact, cryptosystems can easily be broken by side-channel attacks, even though they are considered to be secure in the mathematical point of view. The timing attack(TA) and the simple power analysis attack(SPA) are such side-channel attack methods which can reveal sensitive information by analyzing the timing behavior or the power consumption pattern of cryptographic operations. Thus, appropriate measures against such attacks must carefully be considered in the early stage of cryptosystem's implementation process. The Montgomery multiplier is a commonly used and classical gadget in implementing big-number-based cryptosystems including RSA and ECC. And, as recently proposed as an alternative of building blocks for implementing post quantum cryptography such as lattice-based cryptography, the big-number multiplier including the Montgomery multiplier still plays a role in modern cryptography. However, in spite of its effectiveness and wide-adoption, the multiplier is known to be vulnerable to TA and SPA. And this paper proposes a new countermeasure for the Montgomery multiplier against TA and SPA. Briefly speaking, the new measure first represents a multiplication operand without 0 digits, so the resulting multiplication operation behaves in a very regular manner. Also, the new algorithm removes the extra final reduction (which is intrinsic to the modular multiplication) to make the resulting multiplier more timing-independent. Consequently, the resulting multiplier operates in constant time so that it totally removes any TA and SPA vulnerabilities. Since the proposed method can process multi bits at a time, implementers can also trade-off the performance with the resource usage to get desirable implementation characteristics.

• 한국융합학회논문지
• /
• 제9권8호
• /
• pp.77-85
• /
• 2018

본 연구는 일 지역 내 요양병원의 경도인지장애환자의 일반적 특성, 입원 및 진료특성을 분석하여 경도인지장애 환자에 대한 효율적 관리에 필요한 자료를 제공하고자 시행하였다. 연구대상은 2016년 일 지역에 소재하는 요양병원에서 경도인지장애(F067)를 주진단으로 하는 입원환자 303명의 명세서 건이다. 본 연구결과, 재원일수는 계절별로는 ADL 6~12점, ADL 13~20점 그룹 모두 겨울이 가장 긴 것으로 나타났다. 진료결과는 ADL 6~12점, ADL 13~20점 그룹 모두 퇴원일 때 재원일수가 긴 것으로 나타났다. 총 진료비는 계절별로는 ADL 6~12점, ADL 13~20점 그룹에서 겨울이 높았다. 환자 분류군는 ADL 4~5점 그룹에서는 인지장애군의 진료비가 가장 높았고, ADL 6~12점, ADL 13~20점 그룹 모두 문제행동군이 가장 높은 것으로 나타났다. 이와 같은 결과 경도인지장애에 대한 조기발견과 치료는 잠재적인 치매환자 발생과 그에 따른 사회적 비용 감소에 효과적인 방안이자 대단히 중요한 과제임을 알 수 있다.