• Asia-Pacific Journal of Business
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• v.15 no.1
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• pp.319-334
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• 2024

Purpose - The purpose of this study is to examine the gravity model commonly used for demand forecasting upon the implementation of new tourist facilities and analyze the main causation of forecasting errors to provide a suggestion on how to improve. Design/methodology/approach - This study first measured the errors in predicted values derived from past feasibility study reports by examining the cases of five national science museums. Next, to improve the predictive accuracy of the gravity model, the study identified the five most likely issues contributing to errors, applied modified values, and recalculated. The potential for improvement was then evaluated through a comparison of forecasting errors. Findings - First, among the five science museums with very similar characteristics, there was no clear indication of a decrease in the number of visitors to existing facilities due to the introduction of new facilities. Second, representing the attractiveness of tourist facilities using the facility size ratio can lead to significant prediction errors. Third, the impact of distance on demand can vary depending on the characteristics of the facility and the conditions of the area where the facility is located. Fourth, if the distance value is below 1, it is necessary to limit the range of that value to avoid having an excessively small value. Fifth, depending on the type of population data used, prediction results may vary, so it is necessary to use population data suitable for each latent market instead of simply using overall population data. Finally, if a clear trend is anticipated in a certain type of tourist behavior, incorporating this trend into the predicted values could help reduce prediction errors. Research implications or Originality - This study identified the key factors causing prediction errors by using national science museums as cases and proposed directions for improvement. Additionally, suggestions were made to apply the model more flexibly to enhance predictive accuracy. Since reducing prediction errors contributes to increased reliability of analytical results, the findings of this study are expected to contribute to policy decisions handled with more accurate information when running feasibility analyses.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.5
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• pp.925-936
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• 2023

Currently, due to the rapid increase in power demand and the increase in capacity of power converters, the capacity of electromagnetic contactors is also increasing, and the burden on SMPS for the power that can drive them is increasing. Although the initial starting operation current of an electromagnetic contactor is significantly larger than the holding current for maintaining contact, most electromagnetic contactors apply the same voltage as the initial starting operation. An electromagnetic contactor must continuously apply a holding current to maintain the contact point, and the larger the capacity, the larger the current must be applied. This paper proposes a two-level magnetic contactor drive that allows setting the initial starting operation current to fully attach the contact point of the magnetic contactor and the holding current to maintain subsequent operation. In addition, a low-cost drive topology of analog and digital methods was proposed for various field applications, and an algorithm based on the ripple of the excitation current was proposed to determine whether the magnetic contactor was opened or closed without using a separate contact point. The feasibility of the proposed method was proven through Psim simulation experiments.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.52-61
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• 2018

This research suggested the traffic signal timing calculation model for signal intersections based on sectional travel time. A detection system that collects sectional travel time data such as Urban Transport Information System(UTIS) is applied. This research developed the model to calculate saturation flow rate and demand volume from travel time information using a deterministic delay model. Moreover, this model could determine the traffic signal timings to minimize a delay based on Webster model using traffic demand volume. In micro simulation analysis using VISSIM and its API ComInterface, it checked the saturation conditions and determined the traffic signal timings to minimize the intersection delay. Recently, sectional vehicle detection systems are being installed in various projects, such as Urban Transportation Information System(UTIS) and Advanced Transportation Management System(ATMS) in Korea. This research has important contribution to apply the traffic information system to traffic signal operation sector.

• Journal of Sensor Science and Technology
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• v.31 no.2
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• pp.102-106
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• 2022

Currently, the demand for real-time monitoring of water quality has increased dramatically. Total organic carbon (TOC) analysis is a suitable method for real-time analysis compared with conventional biochemical oxygen demand (BOD) and chemical oxygen demand (COD) methods in terms of analysis time. However, this method is expensive because of the complicated internal processes involved. The photocatalytic titanium dioxide (TiO2)-based TOC method is simpler as it omits more than three preprocessing steps. This is because it reacts only with organic carbon (OC) without extra processes. We optimized the rate between the TiO2 photocatalyst and binder solution and the TiO2 concentration. The efficiency was investigated under 365 nm UV exposure onto a TiO2 coated substrate. The optimized conditions were sufficient to apply a real-time monitoring system for water quality with a short reaction time (within 10 min). We expect that it can be applied in a wide range of water quality monitoring industries.

• The KIPS Transactions:PartC
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• v.16C no.4
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• pp.487-494
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• 2009

VOD(Video On Demand) that provides streaming service according to the user's requirement in real time, consists of the video streaming server and the client system. Since it is very hard to apply the traditional server-client model that a server communicates with many clients through 1:1 connection to VOD system because it requires very high network bandwidth, many researches have been done to address this problem. Batching technique is one of VOD system based on Multicast that requires very small network bandwidth. However, the batching based VOD system has a limitation that it is very hard to provide VCR(Video Cassette Recorder) ability. In this paper, we propose a technique that reduces the required network bandwidth to provide VCR function by using the characteristic of MPEG, one of international video compression standard. In the proposed technique, a new video stream for VCR function is constructed with I pictures that is able to be decoded independently. The new video stream for VCR function is transmitted with the video stream for normal play together in Batching manner. The performance evaluation result shows that the proposed technique not only reduces the required network bandwidth and memory usage but also decreases the CPU usages.

• Proceedings of the Korea Port Economic Association Conference
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• 2006.08a
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• pp.1-12
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• 2006

As national economies globalize, demand for intercontinental container shipping services is growing rapidly, providing a potential economic boon for the countries and communities that provide port services. On the promise of profits, many governments are investing heavily in port infrastructure, leading to a possible glut in port capacity, driving down prices for port services and eliminating profits as ports compete for business. Further, existing ports are making strategic investments to protect their market share, increasing the chance new ports will be overcapitalized and unprofitable. Governments and port researchers need a tool for understanding how local competition in their region will affect demand for port services at their location, and thus better assess the profitability of a prospective port. We propose to develop such a tool by extending our existing simulation model of global container traffic to incorporate demand-side shipper preferences and supply-side strategic responses by incumbent ports to changes in the global port network, including building new ports, scaling up existing ports, and unexpected port closures. We will estimate shipper preferences over routes, port attributes and port services based on US and international shipping data, and redesign the simulation model to maximize the shipper's revealed preference functions rather than simply minimize costs. As demand shifts, competing ports will adjust their pricing (short term) and infrastructure (long term) to remain competitive or defend market share, a reaction we will capture with a game theoretic model of local monopoly that will predict changes in port characteristics. The model's hypotheses will be tested in a controlled laboratory experiment tailored to local port competition in Asia, which will also serve to demonstrate the subtle game theoretic concepts of imperfect competition to a policy and industry audience. We will apply the simulation model to analyze changes in global container traffic in three scenarios: addition of a new large port in the US, extended closure of an existing large port in the US, and cooperative and competitive port infrastructure development among Korean partner countries in Asia.

• The Korean Journal of Applied Statistics
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• v.25 no.1
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• pp.89-99
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• 2012

This study investigates the Granger-causality between economic growth and demand for electricity in Korea, using two quarterly time-series data (real GDP and electricity consumption) for 1970:Q1 through 2009:Q4. We apply Hsiao's sequential procedure to identify a vector autoregressive model to a decision of the optimal lags in the vector error-correction model because the two time-series data contain unit roots respectively and they are cointegrated. According to the empirical results in this study, we find that Hsiao's approach to the Granger-causality indicates a bidirectional causal relation between economic growth and demand for electricity in Korea. Following the Granger and Engle's approach, we also find the statistical evidence on (1) short-run bidirectional causality between real GDP and electricity consumption, (2) bidirectional strong causality between them, and (3) long-run unidirectional causality running from demand for electricity to economic growth. Our results show an inconsistency with the existing studies on Korea's case; however, the results appear to provide more meaningful policy implications for the Korean economy and its strategy of sustainable growth.

• Review of Culture and Economy
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• v.19 no.2
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• pp.29-50
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• 2016

This paper is to apply an individual travel cost method(TCM) to estimate demand functions for cultural services enjoyed by visiting 3 branches of the National Museum of Modern and Contemporary Art located in the Seoul Metropolitan area. This paper extends the standard TCM by incorporating opportunity costs of leisure time and two different data generating process - 398 respondents from an on-site survey and 600 respondents from a general household survey. Negative binomial models reflecting the non-negative integer nature of visiting frequency with over-dispersed variance were best fitted for demand functions, in which residents of Seoul metropolitan area surveyed from on the site exhibited higher visitation demand for the national art museum. Price elasticity and income elasticity differed by respondents' residency. Price elasticity of long distance visitors (-0.21) was more inelastic from those of Seoul residents (-0.34 ~ -0.5). Moreover, regional residents outside of Seoul area seemed to consider that services from the national art museum is a normal good with income elasticity of 0.5, whereas the Seoul residents seemed to perceive it to be an inferior good with income elasticity of -0.05.

• Journal of Digital Convergence
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• v.18 no.11
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• pp.559-569
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• 2020

This study was conducted to examine relationships among job environment, psychological work demand, fatigue, musculoskeletal symptoms, then to investigate the factors influencing musculoskeletal symptoms of care workers in long-term care hospitals. A total of 128 care workers recruited from three long-term care hospitals in S city. Self-reported questionnaire survey was conducted from April to May, 2020. The results were as follows: The musculoskeletal symptoms of the care workers were the sum of the frequency of symptom occurrence, duration of symptoms, and intensity of pain in the three parts of the shoulder, hand/wrist/finger, and waist. The average score was 11.41±9.50 points out of 42. According to the hierarchical regression analysis, their musculoskeletal symptoms were significantly influenced by working department(β=.18, p=.034), psychological work demand(β=.21, p=.013) and fatigue(β=.25, p=.003), explained 21.6% of the total variance(F=6.87, p<.001). Based on our results, in order to reduce musculoskeletal symptoms of care workers in nursing hospitals, it is necessary to develop and apply an intervention program that can reduce psychological work demand and fatigue in consideration of the severity of the patient in charge.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.69
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• pp.261-301
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• 2016

Recently the abusive calls on on-demand bonds have been a critical issue among many engineering and construction companies in Korea. On-demand bond is referred to as an independent guarantee in the sense that the guarantee is independent from its underlying contract although it was issued based on such underlying contract. For this reason, the issuing bank is not required to and/or entitled to look into whether there really is a breach of underlying contract in relation to the call on demand-bonds. Due to this kind of principle of independence, the applicant has to run the risk of the on demand bond being called by the beneficiary without due grounds. Only where the call proves to be fraudulent or abusive in a very clear way, the issuing bank would not be obligated to pay the bond proceeds for the call on on-demand bonds. In order to prevent the issuing bank from paying the proceeds under the on-demand bond, the applicant usually files with its competent court an application for injunction prohibiting the beneficiary from calling against the issuing bank. However, it is in practice difficult for the applicant to prove the beneficiary's call on the bond to be fraudulent since the courts in almost all the jurisdictions of advanced countries require very strict and objective evidences such as the documents which were signed by the owner (beneficiary) or any other third party like the engineer. There is another way of preventing the beneficiary from calling on the bond, which is often utilized especially in the United Kingdom or Western European countries such as Germany. Based upon the underlying contract, the contractor which is at the same time the applicant of on-demand bond requests the court to order the owner (the beneficiary) not to call on the bond. In this case, there apparently seems to be no reason why the court should apply the strict fraud rule to determine whether to grant an injunction in that the underlying legal relationship was created based on a construction contract rather than a bond. However, in most jurisdictions except for United Kingdom and Singapore, the court also applies the strict fraud rule on the ground that the parties promised to make the on-demand bond issued under the construction contract. This kind of injunction is highly unlikely to be utilized on the international level because it is very difficult in normal situations to establish the international jurisdiction towards the beneficiary which will be usually located outside the jurisdiction of the relevant court. This kind of injunction ordering the owner not to call on the bond can be rendered by the arbitrator as well even though the arbitrator has no coercive power for the owner to follow it. Normally there would be no arbitral tribunal existing at the time of the bond being called. In this case, the emergency arbitrator which most of the international arbitration rules such as ICC, LCIA and SIAC, etc. adopt can be utilized. Finally, the contractor can block the issuing bank from paying the bond proceeds by way of a provisional attachment in case where it also has rights to claim some unpaid interim payments or damages. This is the preservative measure under civil law system, which the lawyers from common law system are not familiar with. As explained in this article, it is very difficult to block the issuing bank from paying in response to the bond call by the beneficiary even if the call has no valid ground under the underlying construction contract. Therefore, it is necessary for the applicants who are normally engineering and construction companies to be prudent to make on-demand bonds issued. They need to take into account the creditability of the project owner as well as trustworthiness of the judiciary system of the country where the owner is domiciled.