• Journal of Korea Port Economic Association
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• v.26 no.3
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• pp.130-142
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• 2010

The purpose of this paper is to propose applying agent-based model(ABM) for analyzing logistics system. Logistics problems become more complex and multi-faceted. As a result, the behavior of the system becomes more and more difficult to predict, we see the limitations of the traditional top-down approach in handling complexity. The ABM, that is the bottom-up approach, provides new modeling framework in system modeling. The ABM focuses on the interactions of subsystem or agents in whole system. Then the macroscopic picture of the whole system behavior is emerged as the microscopic interactions of agents are aggregated. The ABM assumes that each agent acts based on simple rules learned from dynamic interactions among other agents or its surrounding environment. The ABM has a great advantage in understanding emergent phenomenon that cannot be explained only through considering individual attributes. The ABM is an extremely useful method to analyze complex system such as logistics system. Therefore, the great research efforts and applications on the ABM to logistics system are encouraged in future.

• Journal of the Economic Geographical Society of Korea
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• v.15 no.4
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• pp.695-707
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• 2012

This study focuses on the importance of macro socio-economic factors to explain the successes of Hallyu(Korean Wave). Studies of Hallyu have mainly discussed the contents of Hallyu products, emphasizing the excellence of Korean culture or cultural similarities in the East Asia. Analyzing cultural industrial factors, the study purports to contribute to more comprehensive explanations of Hallyu. To do so, the study analyzes the Japanese case, because Japan is considered as society where Hallyu is most institutionalized. The study suggests the importance of cultural exchanges between Korea and Japan as the background factors for Hallyu's success in Japan. In addition, the study shows the interactions of 'push factors' in Korea and 'pull factors' from Japan. As for push factors in Korea, this paper suggests the decline of music records(CD and DVD) industry and growing competition in broadcasting industry in Korea. Regarding the pull factors from Japan, robust music industry and changing broadcasting system are discussed. Although this paper try to suggest as many evidences as possible, the macro data suggested are not fully comprehensive enough to explain the importance of cultural industrial factors. In addition, micro-level analyses on the interactions among people who are working in the cultural industries are also necessary, and thus remained for the future studies.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.911-917
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• 2015

The objective of this work focuses on the analysis of injection rate and macroscopic spray behavior characteristics with injection pressures as well as combustion and exhaust emission characteristics with injection timing and injection pressure by using a common rail single-cylinder diesel engine. The injection rate was measured by applying the Bosch method, and macroscopic spray behavior characteristics were analyzed with a constant-volume vessel and a high-speed camera. In addition, combustion and emission characteristics were analyzed in a common-rail single-cylinder diesel engine with precise control of fuel injection timing and pressure. For injection pressures of 30MPa and 50MPa, the injection rate was higher at 50 MPa, and the spray development (penetration) was also higher in the same elapsed time. The peak in-cylinder pressure and rate of heat release showed a tendency to decline as injection timing was delayed, and the peak in-cylinder pressure and rate of heat release were slightly higher for higher injection pressures. Higher injection pressures also reduced the mean effective pressure, while the indicated mean effective pressure and torque increased as injection timing was delayed to TDC. Nitrogen oxides had a peak level at injection timings of $BTDC20^{\circ}$(30MPa) and $BTDC15^{\circ}$(50MPa); carbon monoxide emissions were reduced by delaying injection timing from $BTDC30^{\circ}$.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.226-228
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• 2002

현재 유전자 서열 분석이 완료된 유전체들이 점점 늘어나고 있다. 따라서 이에 대한 방대한 정보가 생성됨에 따라 다양한 생물체들에 대하여 대사 네트웍을 통한 다차원적 분석이 가능하게 되었다. 대사 네트웍은 단백질 또는 효소들의 전체적인 상호작용을 표현하기 때문에 생물학적 메카니즘에 대하여 보다 풍부한 정보를 제공해 준다. 본 논문에서는 일차원적인 유전자 서열에 의한 종의 계통 분류가 아니라 메타 수준의 생리 구조적 비교를 통하여 계통분류학에 대하여 새로운 방법의 접근을 제안하고자 한다. 제안된 방법은 기존의 상동성 비교에 의한 계통 분류와 함께 좀 더 포괄적이고 거시적인 분석을 가능하게 한다.

• Journal of Energy Engineering
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• v.17 no.3
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• pp.145-152
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• 2008

Approaching to the era of high energy price and energy sources scarcity, the demand for governmental intervention to mitigate the short-term shocks is highly increasing. When any energy policy is implemented, double-side effects would be derived. To begin with positive aspect, by decreasing energy import, unnecessary currency outflow can be prevented and the resultant saved money will be appropriately allocated. Furthermore, industrial competitiveness will be assured by reducing use of expensive energy. On the contrary, inappropriate energy saving policy may lead to unexpected negative effects that would hinder improvement in productivity due to indiscreet replacing energy by equipments. In order to enhance effectiveness of energy policy, efforts should be made in advance to understand the energy use pattern of each industry sector which composes the economy. Therefore, in this study, an energy input-output method, one of the macroscopic approaches, is applied to analyze energy use patterns of each industry sector in Korea. Using this method, a quantitative assessment is performed to obtain the energy use intensity and the amount of energy uses with respect to energy types.

• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.163-174
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• 2008

The conventional four-step travel demand model is still widely used as the state-of-practice in most transportation planning agencies even though it does not provide reliable estimates of travel demand. In order to improve the accuracy of travel demand estimation, implementing an alternative approach would be critical as much as acquiring reliable socioeconomic and travel data. Recently, the role of travel demand model is diverse to satisfy the needs of microscopic analysis regarding various policies of travel demand management and traffic operations. In this context, the activity-based approach for travel demand estimation is introduced and a case study of developing a spatial-temporal activity presence-based approach that estimates travel demand through forecasting number of people present at certain place and time is accomplished. Results show that the spatial-temporal activity presence-based approach provides reliable estimates of both number of people present and trips actually people made. It is expected that the proposed approach will provide better estimates and be used in not only long-term transport plans but short-term transport impact studies with respect to various transport policies. Finally, in order to introduce the spatial-temporal activity presence-based approach, the data such as activity-based travel diary and land use based on geographic information system are essential.

• Journal of the Korean Society for information Management
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• v.23 no.3 s.61
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• pp.187-204
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• 2006

The main purpose of the archives is to maintain a history of the organization's functions and activities. Selecting valuable records for the permanent archives through objective appraisal from among many records that reflects the activities of organization is very important but also very difficult. The quantity and complexity of comtemporary records has rapidly expanded because of electronic storage, and with the information environment, and it is now possible to manage and control the records an entire lifetime. In this study, it is proposed the appraisal methods based on a business analysis that is combined the macro-appraisal factor and micro-appraisal factor; The former is functions and organizations as the objective guideline of selecting valuable records from the beginning and the latter is a contents appraisal (evidential value) of the individual records.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.6
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• pp.116-126
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• 2016

In this study, lane-wise traffic flow characteristics were analysed on uninterrupted flow using a new notion of "lane-wise travel speed reversal (LTSR)" which is defined as a phenomena that travel speed in the median lane is lower than other lanes. Mathematical formulation was also proposed to calculate the strength of LTSR. The experiment road site is Seoul Outer Ring Expressway (Jayuro-IC~Jangsoo-IC), and travel trajectories for each four lane were collected for weekdays (Mon. through Fri.) during morning peak. Comparing lane-wise travel speeds for entire test road section, no LTSR was observed, meaning that the travel speed in the median lane is the fastest, followed by 2nd, 3rd, and 4th lane as in order. Howerver, the result of microscopic analysis using 100-meter discrete road section based data shows that LTSR occurs many times. Especially the strength of LTSR is higher in congestion area and freeway merge and diverge segment. It is expected that these results could be used as a fundamental data when establishing lane-by-lane traffic operation strategy and developing lane-wise traffic information collection and dissemination technology.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.539-546
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• 2010

In this paper, lattice Boltzmann method(LBM) results for a laminar flow in a microchannel with rough surface are presented. The surface roughness is modeled as an array of rectangular modules placed on the top and bottom surface of a parallel-plate channel. The effects of relative surface roughness, roughness distribution, and roughness size are presented in terms of the Poiseuille number. The roughness distribution characterized by the ratio of the roughness height to the spacing between the modules has a negligible effect on the flow and friction factors. Finally, a significant increase in the Poiseuille number is observed when the surface roughness is considered, and the effects of roughness on the microflow field mainly depend on the surface roughness.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.9
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• pp.1095-1101
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• 2012

A process heat exchanger (PHE) in a nuclear hydrogen system is a key component that transfers the large amount of heat generated in a very high temperature reactor (VHTR) to a chemical reaction that yields a large quantity of hydrogen. A performance test on a small-scale and a medium-scale PHE prototype made of Hastelloy$^{(R)}$-X is being conducted on in a small-scale nitrogen gas loop at the Korea Atomic Energy Research Institute. Previous research on the macroscopic high-temperature structural analysis of PHE prototypes had been performed using base material properties owing to a lack of weld material properties. In this study, macroscopic high-temperature structural analyses considering the weld material properties were performed and the results were compared with those of a previous study.