• East Asian Economic Review
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• v.26 no.4
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• pp.305-336
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• 2022

This study applied the macro-micro simulation model (i.e., what-if analysis) to investigate the impact of transport related to the Belt and Road Initiative (BRI) on poverty and income inequality in Laos. We selected Laos as a case study of a developing country. We used the standard GTAP model with the GTAP database (version 10) for the macrosimulation, whereas we used the household model with the latest Lao household data from 2019 for the microsimulation. Our findings revealed that the output of the Lao economy was anticipated to increase by up to 0.3%, while the poverty rate was anticipated to decline from 17.0% to 15.7%. However, there would be winners and losers in industries and groups of households in different areas. In particular, rich households with a comparative socioeconomic advantage, such as in education, engagement in nonfarm business, and infrastructure access, would mostly gain benefits; consequently, this would lead to higher inequality in Laos. Therefore, the inequality index (i.e., the Gini coefficient) would increase from 41.2 to 60.1. After a simulation of BRI transport, we also found that some nonpoor households, which are mainly associated with farm activities and lower educational levels, would fall into poverty.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.91-93
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• 2003

It has been estimated that the equivalent of approximately $US 50 billion has been spent on research on the behavior and fate of pesticides in the environment since Rachel Carson published “Silent Spring” in 1962. Much of the resulting knowledge has been summarized explicitly in computer algorithms in a variety of empirical, deterministic, and probabilistic simulation models. These models describe and predict the transport, degradation and resultant concentrations of pesticides in various compartments of the environment during and after application. In many cases the known errors of model predictions are large. For this reason they are typically designed to be “conservative”, i.e., err on the side of over-prediction of concentrations in order to err on the side of safety. These predictions are then compared with toxicity data, from tests of the pesticide on a series of standard representative biota, including terrestrial and aquatic indicator species and higher animals (e.g., wildlife and humans). The models' predictions are good enough in some cases to provide screening of those compounds which are very unlikely to do harm, and to indicate those compounds which must be investigated further. If further investigation is indicated a more detailed (and therefore more complicated) model may be employed to give a better estimate, or field experiments may be required. A model may be used to explore “what if” questions leading to possible alternative pesticide usage patterns which give lower potential environmental concentrations and allowable exposures. We are currently at a maturing stage in this research where the knowledge base of pesticide behavior in the environmental is growing more slowly than in the past. However, innovative uses are being made of the explosion in available computer technology to use models to take ever more advantage of the knowledge we have. In this presentation, current developments in the state of the art as practiced in North America and Europe will be presented. Specifically, we will look at the efforts of the ‘Focus’ consortium in the European Union, and the ‘EMWG’ consortium in North America. These groups have been innovative in developing a process and mechanisms for discussion amongst academic, agriculture, industry and regulatory scientists, for consensus adoption of research advances into risk management methodology.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.112-119
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• 2009

Cam mechanisms are one of the most popular devices for generating irregular motion and are widely used in many automatic equipments, such as textile machinery, internal combustion engines and other automatic devices. In order to obtain the positive motion of follower by rotating cam, its shape should be correctly designed and manufactured. However, complex engineering tasks are required in a design and manufacturing of cams. And also, the manufacturing of general cam is demanded high costs. For the designing of cam, it must be decided that what kind of motion has to be transmitted to follower before selecting the curve of cam and designing profile of cam. However, even though the exact profile of cam is designed at the progress of design, if it doesn't have precision at the manufacturing progress, it's impossible to get expected result. We will develop cam simulation apparatus for measuring cam curve and get profile data before analyzing an error through comparison with design data of cam.

• Journal of Korean Institute of Industrial Engineers
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• v.8 no.1
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• pp.29-39
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• 1982

This paper presents a practical guidence for determining an optimal traffic control system at intersections in the urban areas in Korea. Two alternative systems, unsignalized and signalized, are considered. For analyzing the unsignalized system, two kinds of simulation model are developed ; gap acceptance model and first -in -first - out model. For the signalized system the total delay function for general arrival distribution is developed under the assumption that departure time is constant and it is used to find an optimal cycle time. Finally, the results in these two alternative systems are compared under the minimum average delay criterion and an optimal traffic control system is determined. This approach supports the decision making whether to install a traffic signal system in an intersection with given traffic flows and, if installed, determines what is the optimal cycle time and how the traffic signal phases are divided. And it also gives upper bounds of traffic flows to be passed in the unsignalized and the signalized system, which can be effectively used whenever an intersection is designed.

• Korean Management Science Review
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• v.25 no.1
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• pp.139-147
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• 2008

Conjoint Analysis is marketers' favorite methodology for finding out how buyers make trade-offs among competing products and suppliers. Thousands of applications of conjoint analysis have been carried out over the past three decades. The conjoint analysis has been so popular as a management decision tool due to the availability of a choice simulator. A conjoint simulator enables managers to perform 'what if' question accompanying the output of a conjoint study. Traditionally the First Choice Model (FCM) has been widely used as a choice simulator. The FCM is simple to do, easy to understand. In the FCM, the probability of an alternative is zero until its value is greater than others in the set. Once its value exceeds that threshold, however, it receives 100%. The LOGIT simulation model, which is also called as "Share of Preference", has been used commonly as an alternative of the FCM. In the model part worth utilities aren't required to be positive. Besides, it doesn't require part worth utilities computed under LOGIT model. The simulator can be used based on regression, monotone regression, linear programming, and so on. However, it is not free from the Independent from Irrelevant Alternatives (IIA) problem. This paper proposes the EBA (Elimination-By-Aspects) model as a useful conjoint-like method. One advantage of the EBA model is that it models choice in terms of the actual psychological processes that might be taking place. According to EBA, when choosing from choice objects, a person chooses one of the aspects that are effective for the objects and eliminates all objects which do not have this aspect. This process continues until only one alternative remains.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.89-92
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• 2008

Lecture room, space for student to study, need to get exactly information and show up what students are required So, problems for illuminated environments are low effect of studying, and that students may get weak-sighted. Research is required to get enough lighting for lecture room which students spend most their time. If we compare lighting system for recent college lecture room with computer simulation, lighting system at the lecture room with down light will be improve intensity of illumination. Therefore we can get economical benefit and save energy.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.2
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• pp.159-166
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• 2014

The study is conducted on the subject of optimization of components sizing for series hybrid electric propulsion systems. The components sizing of series type hybrid system is very important because each component of series type is larger than the corresponding component of the parallel type or series-parallel type. If the components sizing is greater or less than what is required to this system, the performance of the system is getting worse. The methodology for the sizing of a driving motor is introduced based on the foundation of determined system configuration and performance target. And the sizing of an engine/generator and a battery is achieved based on simulation results using Dynamic Programming. It is possible to find the optimal sizing of these components by comparing fuel efficiency of hybrid electric propulsion system for 8 driving cycles.

• Journal of the Korea Society of Computer and Information
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• v.23 no.11
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• pp.103-109
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• 2018

This paper presents an idea and framework to automate a full cycle business process management and re-engineering by integrating traditional business process management systems, process mining, data mining, machine learning, and simulation. We build our framework on the cloud-based platform such that various data sources can be incorporated. We design our systems to be extensible so that not only beneficial for practitioners of BPM, but also for researchers. Our framework can be used as a test bed for researchers without the complication of system integration. The automation of redesigning phase and selecting a baseline process model for deployment are the two main contributions of this study. In the redesigning phase, we deal with both the analysis of the existing process model and what-if analysis on how to improve the process at the same time, Additionally, improving a business process can be applied in a case by case basis that needs a lot of trial and error and huge data. In selecting the baseline process model, we need to compare many probable routes of business execution and calculate the most efficient one in respect to production cost and execution time. We also discuss the challenges and limitation of the framework, including the systems adoptability, technical difficulties and human factors.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.602-607
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• 2013

Financial risks associated with capital investments are often measured with different feasibility indicators such as the net present value (NPV), the internal rate of return (IRR), the payback period (PBP), and the benefit-cost ratio (BCR). This paper aims at demonstrating practical applications of probabilistic feasibility analysis techniques for an integrated feasibility evaluation of the IRR and PBP. The IRR and PBP are concurrently analyzed in order to measure the profitability and liquidity, respectively, of a cash flow. The cash flow data of a real wind turbine project is used in the study. The presented approach consists of two phases. First, two newly reported analysis techniques are used to carry out a series of what-if analyses for the IRR and PBP. Second, the relationship between the IRR and PBP is identified using Monte Carlo simulation. The results demonstrate that the integrated feasibility evaluation of stochastic cash flows becomes a more viable option with the aide of newly developed probabilistic analysis techniques. It is also shown that the relationship between the IRR and PBP for the wind turbine project can be used as a predictive model for the actual IRR at the end of the service life based on the actual PBP of the project early in the service life.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1151-1168
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• 2009

Improving packet loss does not necessarily coincide with the improvement in user perceivable QoS because each frame carries different degree of importance. We propose Significance-aware packet scheduling (SAPS) to maximize user perceivable QoS. SAPS carries out two fundamental issues of packet scheduling: "What to transmit" and "When to transmit?" To adapt to the available bandwidth, it is necessarily to transmit the subset of the data packets if the entire set of packets can not be transmitted. "Packet Significance" quantifies the importance of the frame by elaborately incorporating frames' dependency. Greedy approach is used in selecting packets and transmission schedule is determined based on the Packet Significance. The proposed scheme is tested using publicly available MPEG-4 video clips. Decoding engine is embedded in the simulation software and user perceivable QoS is exposeed in termstermiSNR. Throughout the simulation based experiment, the performance of the proposed scheme is compared two other schemes: Size-based packet scheduling and Bit-rate based best effort packet scheduling. SAPS successfully incorporates the semantics of a packet and improves user perceivable QoS significantly. It successfully provides unequal protection to more important packets.