• 산업경영시스템학회지
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• 제24권69호
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• pp.121-132
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• 2001

South and North Korea have many questions pending .Inter-Korea trade is the best actual problem among question pending. The biggest problem of inter-Korea trade in logistics cost. The logistics cost of inter-Korea is the highest position in the middle of foreign trade. We present that the cost reduction is possible by inter-Korea logistics standardization. This paper also shows logistics standardization strategy of South and North Korea.

• 사물인터넷융복합논문지
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• 제9권6호
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• pp.83-92
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• 2023

본 연구 목적은 기업의 지식재산활동을 통한 경영성과를 제고할 수 있는 합리적인 경영전략을 제공하는 것이다. 이러한 연구를 통하여 변화하는 글로벌 환경에서 경쟁력을 강화할 수 있는 대응 방안을 모색하고자 한다. 2023년 9월 1일부터 10월 30일까지 200개 기업을 대상으로 설문조사를 실시하였다. 통계분석은 빈도분석, 탐색적 요인 분석, 신뢰도 분석, 상관관계분석, 다중회귀분석, 차이분석을 실시하였다. 결론은 다음과 같다. 첫째, 지식재산활동에서 경영성과에 미치는 영향은 창출활동과 활용활동으로 나타났다. 둘째, 경영전략에서 경영성과에 미치는 영향은 차별화 전략, 원가우위 전략, 집중화 전략으로 나타났다. 셋째, 원가우위 전략은 지식재산활동의 창출활동과 경영성과의 관계에서 부분매개효과가 확인되었다. 넷째, 차별화 전략은 지식재산활동의 창출활동과 경영성과의 관계에서 부분매개효과가 확인되었다. 또한 차별화 전략은 지식재산활동의 활용활동과 성과의 영향관계에서 완전매개효과가 확인되었다. 다섯째, 집중화 전략은 지식재산활동의 활용활동과 경영성과의 관계에서 부분매개효과가 확인되었다. 여섯째, 벤처인증 여부에 따른 창출활동, 보호활동, 활용활동, 원가우위 전략, 차별화 전략, 재무성과, 비재무성과는 차이가 나타났다. 기술패권 시대에 지식재산의 중요성은 높아지고 있기 때문에 사물인터넷 기업의 미래 경쟁력 확보를 위해서는 기업의 벤처 인증과 지식재산을 활용한 전략으로 경영성과를 상승시켜야 할 것이다. 이러한 연구를 기반으로 사물인터넷 기업이 지식재산활동을 고려한 효율적인 전략 추진으로 성과가 극대화되길 기대한다.

• Journal of Microbiology and Biotechnology
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• 제25권2호
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• pp.185-195
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• 2015

Glucoamylase is an important industrial enzyme. Glucoamylase production by industrial Aspergillus niger strain featured with two major problems: (i) empirical substrate feeding methods deteriorating the fermentation performance; and (ii) the high raw materials cost limiting the economics of the glucoamylase product with delegated specification. In this study, we first proposed a novel three-stage varied-rate substrate feeding strategy for efficient glucoamylase production in a 5 L bioreactor using the standard feeding medium, by comparing the changing patterns of the important physiological parameters such as DO, OUR, RQ, etc., when using different substrate feeding strategies. With this strategy, the glucoamylase activity and productivity reached higher levels of 11,000 U/ml and 84.6 U/ml/h, respectively. The performance enhancement in this case was beneficial from the following results: DO and OUR could be controlled at the higher levels (30%, 43.83 mmol/l/h), while RQ was maintained at a stable/lower level of 0.60 simultaneously throughout the fed-batch phase. Based on this three-stage varied-rate substrate feeding strategy, we further evaluated the economics of using alternative carbon sources, attempting to reduce the raw materials cost. The results revealed that cornstarch hydrolysate could be considered as the best carbon source to replace the standard and expensive feeding medium. In this case, the production cost of the glucoamylase with delegated specification (5,000 U/ml) could be saved by more than 61% while the product quality be ensured simultaneously. The proposed strategy showed application potential in improving the economics of industrial glucoamylase production.

• KIEAE Journal
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• 제15권4호
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• pp.37-43
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• 2015

Purpose : The study applied control strategy to reduce through optimal control and operation of pump by applying control on variable speed to the circulation pump of HVAC system in the office building. The study has the purpose to review validity of control on variable speed as ESMs(Energy Saving Measures) and establish the control technology on variable speed pump. The study performed reduction analysis of building energy and economic evaluation of pump through energy effectiveness control strategy of HVAC system. Method: The study sought possible reduction through energy control strategy which can provide proper flow fitting to building load by applying control on variable speed pump. The study applied control strategy to reduce through pressure differential set-point control and operation of pump by applying control on variable speed to the circulation pump of HVAC system in the office building. Result : The results showed that about 16-35% of pump energy could be saved by using these optimal control strategies. In the result of analysis on 10 years life cycle cost of analysis on payback period of initial investment pump, variable speed pump control showed 5.1 years.

• Journal of applied mathematics & informatics
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• 제39권5_6호
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• pp.895-918
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• 2021

Human African Trypanosomiasis (HAT) also known as sleeping sickness, is a neglected tropical vector borne disease caused by trypanosome protozoa transmitted by bites of infected tsetse fly. The basic reproduction number, R₀ derived using the next generation matrix method which shows that the disease persists in the population if the value of R₀ > 1. The numerical simulations of optimal control model carried out to determine the control strategy that can combat HAT under the minimum cost. The results indicate that, the use of both education campaign, treatment and insecticides are more efficient and effective to eliminate HAT in African community but too costly. Furthermore, the cost-effectiveness of the control measures (education campaign, treatment and insecticides) were determined using incremental cost-effectiveness ratio (ICER) approach and the results show that, the use of education and treatment of infected people as the best cost effective strategy compared to other strategies.

• 한국정보과학회논문지:데이타베이스
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• 제37권3호
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• pp.165-170
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• 2010

본 논문에서는 센서 네트워크에서 효율적인 조인 처리를 수행하여 통신비용을 최소화할 수 있는 인-네트워크 조인 기법인 SBJ(Semi & Bloom Join)를 제안하였다. SBJ는 하이브리드 기법으로 배터리 소모를 줄이기 위하여 송, 수신하는 데이터의 크기를 줄이는 방법으로 블룸 필터(Bloom Filter)를 이용하여 데이터의 내용을 필터링하도록 하였다. 기존 데이터 대신 작은 크기의 필터링 된 값을 전송함으로써 배터리 소모를 줄이게 된다. SBJ는 조인 처리의 이른 단계에서 조인 결과에 해당되지 않는 데이터를 제거하여 불필요한 통신비용을 감소하여 통신비용을 최소화하기 위한 네트워크 내에서 효율적인 조인 질의 수행 방법이다. 시뮬레이션을 통하여 기존의 조인 기법들과 비교한 결과 SBJ 기법은 블룸 필터를 이용하여 데이터를 필터링 함으로서 센서 노드 배터리 소모량을 크게 줄였으며, 통신 반경에 대한 통신비용도 훨씬 효과적이었다.

• Smart Structures and Systems
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• 제18권3호
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• pp.569-584
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• 2016

This paper presents a method for stochastic modelling of fatigue crack growth and optimising inspection and maintenance strategy for the structural members of steel bridges. The fatigue crack evolution is considered as a stochastic process with uncertainties, and the Gamma process is adopted to simulate the propagation of fatigue crack in steel bridge members. From the stochastic modelling for fatigue crack growth, the probability of failure caused by fatigue is predicted over the service life of steel bridge members. The remaining fatigue life of steel bridge members is determined by comparing the fatigue crack length with its predetermined threshold. Furthermore, the probability of detection is adopted to consider the uncertainties in detecting fatigue crack by using existing damage detection techniques. A multi-objective optimisation problem is proposed and solved by a genetic algorithm to determine the optimised inspection and maintenance strategy for the fatigue affected steel bridge members. The optimised strategy is achieved by minimizing the life-cycle cost, including the inspection, maintenance and failure costs, and maximizing the service life after necessary intervention. The number of intervention during the service life is also taken into account to investigate the relationship between the service life and the cost for maintenance. The results from numerical examples show that the proposed method can provide a useful approach for cost-effective inspection and maintenance strategy for fatigue affected steel bridges.

• 한국데이타베이스학회:학술대회논문집
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• 한국데이타베이스학회 1998년도 국제 컨퍼런스: 국가경쟁력 향상을 위한 디지틀도서관 구축방안
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• pp.3-48
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• 1998

Drivers for Increased Need for Digital Content ■ Falling cost of computing -Multimedia capability at reasonable cost ■ Decrease in digital storage cost -Magnetic, optical and tape -Cost of digital storage decreases 40％ / year ■ World Wide Web users explosion and falling cost of communications -17M web servers(1/97) -Number of users doubles every 6 months - Network bandwidth triples every year(omitted)

• 대한전자공학회논문지TC
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• 제42권7호
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• pp.1-6
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• 2005

증가하는 이동 통신망 가입자를 수용하기 위한 셀 크기의 소형화는 잦은 위치 갱신을 유발시켜 위치 관리 비용의 증가를 가져왔다. 본 논문에서는 [l]에서 향후과제로 남겨두었던 호 수신 확률에 근거한 위치 관리 기법의 비용을 분석하여 제안된 기법이 기존의 방식(IS-41)보다 위치 관리 비용을 줄일. 수 있음을 증명하였다. 그리고 분석에 의해 계산된 위치 관리 비용을 시뮬레이션 결과와 비교해 보았다. 그 결과, 제안된 기법은 단말의 호 도착률이 낮은 경우, 위치 갱신을 생략하는데서 얻어지는 비용의 감소로 기존의 위치 관리 기법보다 전체 위치 관리 비용을 줄일 수 있으며, 호 도착률이 높아지더라도 위치 관리 비용이 기존 방식의 위치 관리 비용을 초과하지 않음을 보였다.

• 한국항해항만학회지
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• 제38권6호
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• pp.567-575
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• 2014

In recent times, an obvious strategy in liner shipping markets that has come to the fore is slow steaming. Nowadays, most liner shipping companies have decelerated the voyage speed to 15-18 knots on major routes, and some leading liner shipping companies have a plan to reduce it to below 15 knots. Slow steaming is helpful in reducing the operating cost and the amount of greenhouse-gas emissions on a single vessel with lower fuel consumption. However, it also creates various negative effects such as the opportunity cost, additional fixed costs and an in-transit inventory cost on a loop. Hence, the net operating cost on a loop is changing dynamically due to the changes of voyage speed based on various slow steaming effects. The aim of this study is to analyze the slow steaming effects in the liner shipping, and to find the best voyage speed that minimizes the operating cost on a loop. Moreover, this study suggests the recommendable strategy for liner shipping companies. To achieve the aim of this study, a simulation model has been designed using System Dynamics.