• Industrial Engineering and Management Systems
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• v.12 no.3
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• pp.172-180
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• 2013

We herein consider a stochastic multi-item inventory management problem in which a warehouse sells multiple items with stochastic demand and periodic replenishment from a supplier. Inventory management requires the timing and amounts of orders to be determined. For inventory replenishment, trucks of finite capacity are available. Most inventory management models consider either a single item or assume that multiple items are ordered independently, and whether there is sufficient space in trucks. The order cost is commonly calculated based on the number of carriers and the usage fees of carriers. In this situation, we can reduce future shipments by supplementing items to an order, even if the item is not scheduled to be ordered. On the other hand, we can reduce the average number of items in storage by reducing the order volume and at the risk of running out of stock. The primary variables of interest in the present research are the average number of items in storage, the stock-out volume, and the number of carriers used. We formulate this problem as a multi-objective optimization problem. In a numerical experiment based on actual shipment data, we consider the item shipping characteristics and simulate the warehouse replenishing items coordinately. The results of the simulation indicate that applying a conventional ordering policy individually will not provide effective inventory management.

• Structural Engineering and Mechanics
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• v.41 no.4
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• pp.559-573
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• 2012

An adaptive modeling and simulation technique is introduced for the effective and reliable fluid-structure interaction analysis using MSC/Dytran for large-scale complex pressurized liquid containment. The proposed method is composed of a series of the global rigid sloshing analysis and the locally detailed fluid-structure analysis. The critical time at which the system exhibits the severe liquid sloshing response is sought through the former analysis, while the fluid-structure interaction in the local region of interest at the critical time is analyzed by the latter analysis. Differing from the global coarse model, the local fine model considers not only the complex geometry and flexibility of structure but the effect of internal pressure. The locally detailed FSI problem is solved in terms of multi-material volume fractions and the flow and pressure fields obtained by the global analysis at the critical time are specified as the initial conditions. An in-house program for mapping the global analysis results onto the fine-scale local FSI model is developed. The validity and effectiveness of the proposed method are verified through an illustrative numerical experiment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.8
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• pp.124-129
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• 2009

Recently, there has been a growing global interest in environmental conservation, and the field of electric power equipment has been working to become more environment-friendly. Accordingly the 154[kV] low noise transformer is developed through the research. The low noise transformer decreases the audible noise level but the low noise transformer has several changes in the increase of weight and volume and the application of rubber damper. Therefore it is necessary to inspect the test, transportation, installation and operation about field application. In this paper, we investigate the standards of the audible noise level, the weight and volume of the transportation, the installation space and operation in order for effective field application.

• Korea-Australia Rheology Journal
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• v.12 no.1
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• pp.83-92
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• 2000

In resin transfer molding (RTM) process, preplaced fiber mat is set up in a mold and thermoset resin is injected into the mold. An important interest in RTM process is to minimize cycle time without sacrificing part quality or increasing cost. In this study, the numerical simulation and optimization process in filling stage were conducted in order to determine the optimum gate locations. Control volume finite element method (CVFEM) was used in this numerical analysis with the coordinate transformation method to analyze the complex 3-dimensional structure. Experiments were performed to monitor the flow front to validate simulation results. The results of numerical simulation predicted well the experimental results with every single, simultaneous and sequential injection procedure. We performed the optimization analysis for the sequential injection procedure to minimize fill time. The complex geometry of an automobile bumper core was chosen. Genetic algorithm was used in order to determine the optimum gate locations with regard to 3-step sequential injection case. These results could provide the information of the optimum gate locations in each injection step and could predict fill time and flow front.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1896-1897
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• 2007

Medical equipment of high frequency has been presently applied to various parts of human body and novel treatment effects have been shown by it. Recently there are many cases that high frequency apparatus has been used in dermatology as the interest in beauty has been growing. Especially used in skin, blood volume is increased by keeping surface temperature of skin at around $43^{\circ}C$ and domodex folliculorum are treated by applying high electric field. It is the aspect we consider that increasing blood volume and domodex folliculorum treatment take effect on hair loss. In this study, high frequency electrotherapy apparatus was proposed to be applied to hair loss treatment. For that, human body was experimented with varying output voltage and frequency. The adjustable switching signal for treatment was obtained from 100[kHz] to 1000[kHz] by using DSP. Stable output specific was also obtained by feedback control to protect human body. The best hair growth conditions were the output voltage of 1.2[kV], the frequency of near 300[kHz] and the maximum current of 2[mA]. We apply this high frequency electrotherapy apparatus to two bald men, 46-year-old and 45-year-old. After treatment for a month they had thick and strong hair.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.75
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• pp.95-116
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• 2017

The global financial crisis has slowed overall growth in the global economy. In addition, uncertainty is increasing in the world economy due to the Trade protectionism, sluggish world trade, and a rise in the rate of interest caused by expansion of fiscal spending by major countries. In this study, we analyzed various factors affecting the container import and export volume, which has a high correlation with export and import of commodities in international trade. In particular, we will examine how exchange rate fluctuations and domestic and overseas economic conditions affect container imports and exports. For the empirical analysis, monthly time series data were used from January 2000 to January 2017. We use the Error Correction Model (VECM) for the empirical analysis and the GARCH model for the exchange rate fluctuation. As a result, container export and import volume had a negative relationship with exchange rate and exchange rate volatility, which had a positive effect on domestic and international economic conditions. However, the effects are different before and after the financial crisis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.560-565
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• 2016

In this study, we empirically scrutinize the relationship between short selling transactions and stock price behaviors using the stock market data in Korea during the period from January 2005 to March 2016. We chose the short selling volume ratio (SVR), stock lending volume ratio (LVR), and stock lending open interest ratio (LIR) as variables of the short selling trading activities. We construct portfolios based on the percentile of the short selling volume ratio during the sample period; upper-10%-SVR portfolio, upper-25%-SVR portfolio, upper-50%-SVR portfolio. We estimate the monthly firm-specific return and monthly skewness of the daily firm-specific returns of each portfolio. The firm-specific return or skewness is specified as a dependent variable and the short selling activities as explanatory variables. The results show that all of the statistically significant estimates of the short selling activities for the firm-specific returns are negative and that all of the statistically significant estimates of the skewness of the short selling activities are positive. These results support the hypothesis that short selling activities cause the stock price to decrease.

• Journal of Oriental Neuropsychiatry
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• v.34 no.3
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• pp.235-245
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• 2023

Objectives: The aim of this study was to analyze public and researcher interests in suicide and related illnesses and acupuncture and acupressure treatment using Google Trends and some electronic databases. Methods: Search results for keywords "suicide," "acupuncture," "acupressure," and several illnesses related to suicide were analyzed in Google Trends from January 2004 to June 2023. Illnesses included anxiety, depression (including major depressive disorder), schizophrenia, bipolar disorder, post- traumatic stress disorder (PTSD), eating disorder (including anorexia nervosa and bulimia nervosa), substance use disorder, autism spectrum disorder, personality disorder (including borderline person- ality disorder), and chronic pain. Search results were extracted using relative search volume (RSV) scores between 0 and 100. Search terms were also searched in online databases, including PubMed, CNKI, and OASIS, to estimate the number of related studies, and descriptive analysis was conducted. Results: Google Trends analysis showed a strong positive correlation between the RSVs of "suicide and depression," "acupuncture and chronic pain," and "acupressure and PTSD." The electronic database search results produced numerous studies published on "suicide and depression," "acupuncture and depression," and "acupressure and anxiety." High interest in "suicide and depression," "acupuncture and chronic pain," and "acupressure and anxiety" was seen among the public and researchers. Interest in "suicide and chronic pain," "acupuncture and eating disorder," and "acupressure and PTSD" was higher in the public than among researchers, while "anxiety and suicide" and "anxiety and acu- puncture" showed opposite trends. Conclusions: The results of this research enable an understanding of public and researcher interest in suicide, acupuncture, acupressure, and suicide-related illnesses. The results also provide a basis for fu- ture research and examining public health implications in Korean medicine.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.2
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• pp.101-108
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• 2014

As browsing and sharing multimedia contents through various social network services have become very common these days. there has been a rising demand for effectively provide appropriate multimedia contents to users depending on their interest and characteristics. Especially, considering the enormous volume of multimedia contents created daily, user satisfaction heavily depends on effective selection of appropriate multimedia contents. For instance, if the acquisition of contents is based on friends or related people, then it is usually considered to be more trustworthy. Facebook page is one of the social spaces where people can obtain various information of interest. Still, users have difficulty in finding proper information because Facebook generates tremendous amount of data daily. In this paper, we proposed a scheme to extract and select Facebook page contents effectively. In our proposed scheme, users are grouped based on mutual intimacy and Facebook pages of interest are selected based on the ranking of importance. We show the performance of our scheme through experiments.

• Journal of the Korean Institute of Gas
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• v.25 no.2
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• pp.28-33
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• 2021

With the recent growing interest in eco-friendly cars, as interest in eco-friendly cars increases, interest and purchase of hydrogen fuel cell vehicles that do not emit pollutants are increasing. Recently, the government is supporting the expansion of hydrogen charging station and localization of core parts according to the government's hydrogen energy dissemination policy. In this study, the flow characteristics of the hydrogen flow control valve were investigated. As the differential pressure increases, the mass flow rate and flow coefficient tend to be different from the volume flow rate. And it was confirmed that it affects the hydrogen temperature due to the nozzle effect in the bottleneck section, and the change in density affects the mass flow rate.