• 한국안전학회지
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• 제35권6호
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• pp.78-84
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• 2020

The F&EI technique is one of the risk assessments with many advantages. It can save time and effort compared to quantitative risk assessment (QRA). By using the evaluation result of this technique, it is possible to check the effectiveness of the investment cost. In addition, a relative risk ranking can be created and used to establish the facility management cycle and to prioritize investment. However, evaluating the target process can be evaluated more than the actual risk since the LCCF, a loss prevention measure, is too limited. In addition, calculating premiums via this method can result in excessive premiums, making it difficult to evaluate the risk precisely. Therefore, new safety guard was added to the LCCF of the F&EI risk assessment with reference to HAZOP and LOPA techniques. Newly added LCCFs are Deflagration arrester, Check valve, SIS, and Vacuum beaker, etc. As a case study, F&EI risk assessment was performed on Acetone storage tank of a API (Active pharmaceutical ingredient) plant to compare actual MPPD. The estimated loss amount was 592,558$ for the existing technique and 563,571$ for the improved technique, which was reduced by about 5% compared to the previous one.This proved that a more precise evaluation is possible and that the efforts for safety at the workplace are reflected in the evaluation results.

• 한국응급구조학회지
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• 제25권3호
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• pp.127-143
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• 2021

Purpose: The purpose of the study is to investigate the actual state of activity on domestic and foreign civil anti-disaster organizations, related suggestions, and development plans. Methods: This study used the documentary survey research method and the technical approach method. Civil anti-disaster organizations' information was derived from detailed scholarly monographs, specialty publications, and previous studies of master doctorate dissertation. Results: Volunteer Fire Department and voluntary crime prevention groups show problems related to budgetary deficits and volunteer deficiency. In order to resolve these issues, laws must be enacted to guarantee interest and support. In addition, the Citizen Corps Active in Disaster (CAIND) organization requires a dedicated salary system to address the investment of its workforce and the cost of heavy equipment. Moreover, deficiencies were revealed regarding the lack of systems in support of occupational education and training. In conclusion, several weak points require close attention. Conclusion: The results of this comparative analysis study about the domestic and foreign civil anti-disaster organizations provide insight into identity materialization and concept establishment.

• 한국도로학회논문집
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• 제18권1호
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• pp.99-107
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• 2016

PURPOSES : This study was initiated to estimate expressway traffic congestion costs by using Vehicle Detection System (VDS) data. METHODS : The overall methodology for estimating expressway traffic congestion costs is based on the methodology used in a study conducted by a study team from the Korea Transport Institute (KOTI). However, this study uses VDS data, including conzone speeds and volumes, instead of the volume delay function for estimating travel times. RESULTS : The expressway traffic congestion costs estimated in this study are generally lower than those observed in KOTI's method. The expressway lines that ranked highest for traffic congestion costs are the Seoul Ring Expressway, Gyeongbu Expressway, and the Youngdong Expressway. Those lines account for 64.54% of the entire expressway traffic congestion costs. In addition, this study estimates the daily traffic congestion costs. The traffic congestion cost on Saturdays is the highest. CONCLUSIONS : This study can be thought of as a new trial to estimate expressway traffic congestion costs by using actual traffic data collected from an entire expressway system in order to overcome the limitations of associated studies. In the future, the methodology for estimating traffic congestion cost is expected to be improved by utilizing associated big-data gathered from other ITS facilities and car navigation systems.

• 대한조선학회논문집
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• 제58권5호
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• pp.294-302
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• 2021

In this study, the 3D printing technique called design for additive manufacturing (DfAM) that is widely used in various industries was applied to marine leisure ships of equipment. The DfAM for the stanchion for crew safety was applied to the equipment used in an actual recreational craft. As design constraints, the design alternatives were not to exceed the safety and weight of the existing stainless steel material, which were reviewed, and the production of a low-cost FFF-type 3D printing method that can be used even in small shipyards was considered. Until now, additive manufacturing has been used for manufacturing only prototypes owing to its limitations of high manufacturing cost and low strength; however, in this study, it was applied to the mass production process to replace existing products. Thus, a design was developed with low manufacturing cost, adequate performance maintenance, and increased design freedom, and the optimal design was derived via structural analysis comparisons for each design alternative. In addition, a life-cycle assessment based on the ISO 1404X was conducted to develop sustainable products. Through this study, the effectiveness of additive manufacturing was examined for future applications in the shipbuilding industry.

• 동아시아식생활학회지
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• 제13권6호
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• pp.501-513
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• 2003

This study was conducted to investigate the relationship between general characteristics and the eating-out behaviors of 643 male/female industrial workers. The results of the study was summarized as follows. 1. The frequency rate of eating-out was higher for male than female, college graduates than high school graduates, high income earner than low income earner, and unmarried than married(p<0.05). 2. Average cost for eating-out was higher for male than female, for high educated and high income earner than low educated person. Age, married or not, personal health conditions and BMI, however, didn't make any difference in the average cost for eating-out. 3. Reasons fur eating-out was very different due to gender, age, degree of education income rate, married or not, BMI(p<0.05) but basically eating-out was due to get together with friends or colleagues. Also, people who thought they were not in good health answered that they did not eat-out in any conditions. Overweighted people ate out more often than normal or under-weighted people. 4. The method in gathering information about eating-out was different according to the level of education and whether married or not. On the other hand, gender, age, income rate, personal health condition and BMI did not make a big difference in its method. However, most People who Participated in the survey gathered information from people around them, such as friends/colleagues. 5. Taste was the most important factor in deciding the actual eating-out restaurant among the respondents and gender, age, level of education, married or not also made significant differences (p<0.05). 6. Besides personal health conditions and BMI, all the general characteristics including age made significant differences in selecting the most frequently visited restaurant. 7. Besides the personal health conditions, the transportation vehicle was different due to gender, age, level of education, income rate, married or not and BMI. As seen from the results, the eating-out behaviors mostly differed due to general characteristics. In order to searching for a new eating-out market, the general characteristics and the trend of the target customers has to be analyzed to activate the eating-out industry. In addition the need for highly nutritional food with low calorific value has to be emphasized along with the taste.

• 정보보호학회논문지
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• 제29권6호
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• pp.1413-1424
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• 2019

암호 화폐는 블록체인 합의 프로토콜의 확장성 문제들로 인하여 실제 지불 수단으로 사용되기에는 한계점이 존재하였으며, 이러한 한계점들을 해결하기 위한 다양한 오프체인 솔루션들이 연구되고 있다. 본 논문에서는 단방향 해시 함수를 활용한 효율적인 오프체인 결제 채널을 설계하고 설계한 결제 채널을 이더리움 스마트 컨트랙트를 사용하여 구현하였으며 이전에 구현되었던 플라즈마 MVP와 동일한 환경에서 배포하여 각 메소드에 대한 실행 시간과 비용을 측정 및 분석하는 실험을 진행하였다. 그 결과, 플라즈마 MVP와 비교하여 제안된 솔루션은 전체 누적 시간의 경우에는 약 34%로 단축할 수 있었으며 전체 실행 비용은 약 41%로 절약할 수 있었다.

• 한국산학기술학회논문지
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• 제20권10호
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• pp.468-477
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• 2019

다양한 재료와 신기술의 개발로 방수공사 시공방법이 변화되고 현장에 적용되고 있으나, 공사비산정기준은 현장실태를 제대로 반영하지 못하고 있다. 본 연구에서는 공사비산정기준을 개정하기 위해 시방기준분석과 현장실태 조사를 통한 주요개정내용 및 결과를 분석하였다. 먼저 현재 공사비산정기준에서 정하는 각 항목들을 분석하여 현장조사를 통한 실태와 비교 분석하였다. 주요 조사 내용으로는 현장의 바탕면 품질수준 향상으로 바탕처리 난이도가 감소하였으며, 재료의 기능향상으로 시공시간 단축과 다양한 시공방 법이 적용되고 있었다. 또한, 두 가지 이상의 재료를 복합적으로 사용하는 복합방수공법의 적용이 늘어나고 있었으며, 시공장소, 부위에 따라 생산성의 차이가 나타나는 것으로 분석되었다. 이 결과를 바탕으로 방수항목을 세분화하여 복합공법에 적용이 가능하도록 하였으며, 재료별, 시공방법별 투입 품을 차별화 하였다. 시공부위에 따라 구분된 기준을 제시하며, 적용성이 떨어지는 항목은 삭제하여 시방기준에 적합하고 현장시공실태를 반영한 개정으로 공사비산정기준의 적정성이 확보되었다. 향후 시방기준과 현장의실태의 변화에 유연하게 대응할 수 있는 세부화된 공사비산정기준 마련이 필요하다.

• Ocean and Polar Research
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• 제40권4호
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• pp.237-247
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• 2018

This study aims to estimate optimal harvests, fishing efforts, and stock levels of hairtail harvested by the large pair bottom trawl, the large otter trawl, the large purse seine, the offshore long line, and the offshore angling fisheries by using the surplus production models and the current value Hamiltonian method. Processes of this study are as follows. First of all, this study estimates the standardized fishing efforts regarding the harvesting of the hairtail by the above five fishing gears based on the general linear model developed by Gavaris. Secondly, this study estimates environmental carrying capacity (k), intrinsic growth rate (r), and catchability coefficient (q) by applying the Clarke Yoshimoto Pooley (CY&P) model among various surplus production models. Thirdly, this study estimates the optimal harvests, fishing efforts, and stock levels regarding the hairtail by the current value Hamiltonian method, including the average landing price, the average unit cost, and the social discount rate. Finally, this study attempts a sensitivity analysis to figure out changes in optimal harvests, fishing efforts, and stock levels due to changes in the average landing price and the average unit cost. As results induced by the current value Hamiltonian method, the optimal harvests, fishing efforts, and stock levels regarding the hairtail caught by several fishing gears were estimated as 33,133 tons, 901,080 horse power, and 79,877 tons, respectively. In addition, from the results of the sensitivity analysis, first of all, if the average landing price of the hairtail constantly increases, the optimal harvests of it increase at a decreasing rate, and then harvests finally slightly decrease as a result of decreases in stock levels. Secondly, if the average unit cost of fishing efforts continuously increases, the optimal fishing efforts decreases, but optimal stock levels increase. Optimal harvests start climbing and then decrease continuously due to increases in the average unit cost. In summary, this study suggests that the optimal harvests (33,133 tons) were larger than actual harvests (25,133 tons), but the optimal fishing efforts (901,080 horse power) were much less than estimated standardized fishing efforts (1,277,284 horse power), corresponding to the average of the recent three years (2014-2016). This result implies that the hairtail has been inefficiently harvested and recently overfished due to excessive fishing efforts. Efficient management and conservation policies on stock levels need to be urgently implemented. Some appropriate strategies would be to include the hairtail in the Korean TAC species or to extend the closed fishing season for this species.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제1권2호
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• pp.79-86
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• 2012

선박경제운항이란 기상예측정보를 활용하여 연료소모량을 최소화하도록 선박을 운항하는 것으로서 최근 다양한 선박경제운항 시스템이 연구되고 있다. 성공적인 선박경제운항을 위해서는 효율적인 최적의 지리적 경로탐색 방법이 필요한데 기존의 시스템에서는 주로 Dijkstra 알고리즘 기반의 최소정적비용 경로탐색 알고리즘으로 접근하고 있다. 그러한 접근법을 적용하기 위해서는 특히 연료소모량으로 정의되는 간선의 비용을 고정해야 하는데 선박이 그 간선을 실제 지날 때의 기상 상황에 따라 연료소모량이 변할 수 있다는 점에서 적절하지 않은 가정이다. 이에 본 논문에서는 그러한 단점을 극복하기 위해 Dijkstra 알고리즘을 변형한 최소동적비용 경로탐색 알고리즘을 제안한다. 또한, 실행시간을 단축하기 위해 $A^*$ 알고리즘을 활용하여 탐색공간을 효과적으로 줄이기 위한 방법도 제시한다. 총 10개의 테스트 노선에 대해서 본 논문에서 제안된 시스템을 기존의 단순한 최단거리 운항방법과 비교한 결과, 운항소요시간은 거의 차이가 없으면서도 연료소모량을 평균 2.36%, 최대 4.82% 개선시킬 수 있었다.

• 응용통계연구
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• 제31권5호
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• pp.587-597
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• 2018

조사목적에 부합하는 표본 자료를 얻기 위해서는 추출방법 및 조사방법 결정, 설문지 작성 등의 절차가 필요하며 중요한 결정 중 하나가 표본크기 공식의 적용이다. 표본크기 공식은 추출방법에 따른 목표오차와 총비용 등을 설정함으로써 결정되는데 본 논문에서는 단순임의추출에서 목표오차와 예상 응답률이 주어져 있을 때 과거 및 현재 시점의 모집단의 변동과 과거 자료의 추정오차 및 응답률을 사용한 표본크기 공식을 제안한다. 실제조사에서는 설계가중치 외에도 여러 가중치가 복합적으로 적용되는 추정량을 사용하고 있는데 본 논문에서는 설계가중치와 무응답 보정계수를 사용한 추정량에서의 표본크기 공식을 유도하며 이것은 시점별 조사방법이 달라질 경우 응답률에 차이가 발생하는 현상을 반영한 공식이 될 수 있다. 또한 모의 실험을 통하여 기존의 표본크기 공식과 비교함으로써 제안된 공식의 다양한 적용방안을 살펴본다.