• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.3
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• pp.1-15
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• 2007

In this paper, the return link of interactive GEO satellite network providing multimedia services is considered. First, we classify data by delay characteristics, and analyze the numbers of expected lost packets and expected delay packets for each data class of each terminal. Next we mathematically formulate optimal rate scheduling model to minimize the weighted sum of the numbers of expected lost packets and expected delay packets considering priority of each data class. We also suggest a dynamic rate scheduling scheme based on Lagrangean relaxation technique and subgradient technique to solve the proposed model in a fast time. Extensive experiments show that the proposed scheme provides encouraging results.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.263-268
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• 2011

There are many exclusive freight cars in railway freight transportation system. Gondola is one kind of freight cars. Gondolas have a role to carry bulk-type cargo such as coals and ores. A few problems are occurring due to exclusive freight cars. Operation company has redundant freight cars because exclusive freight cars can carry limited items. And purchasing cost of freight cars is higher and higher because of irregular bid. Operation efficiency of gondola is very low because return time of gondola is much longer than that of container car. In this study, we analysed the introduction effect of hopper-type container for through transit. First, we identified the characteristics of spatial distribution on freight stations. And we provided the effect of hopper-type container in terms of operation efficiency, cost reduction, new demand excavation and image enhancement of eco-friendly railroad.

• Journal of the Korea Safety Management & Science
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• v.15 no.3
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• pp.143-150
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• 2013

A cell site lease is a legal agreement by which the owner of a building or a piece of land allows a wireless carrier to use part of it for a cell tower for a period of time in return for money. Wireless carriers spend significant money for cell site leases. This paper tries to find factors affecting cell site leases and management solutions to save lease costs. In other words, this research identifies any factor influencing cell site leases among age, gender, and geographical area in the first problem and determines management priorities using an importance-satisfaction model in the second problem. This paper can provide wireless carriers with effective decision making tools and a basis for negotiation of cell site leases, as they do not have enough bases for negotiation.

• The Korean Journal of Financial Management
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• v.26 no.4
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• pp.191-234
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• 2009

This study examined on the volatility feedback hypothesis through the use of threshold GARCH-in-Mean (GJR-GARCH-M) model developed by Glosten, Jaganathan, and Runkle (1993) in the stock markets of 14 emerging countries during the period of January, 1996 to May, 2009. On this study, I found successful evidences which can support the volatility feedback hypothesis through the following three estimation procedures. First, I found relatively strong positive relationship between the expected market risk premiums and their conditional standard deviations from the GARCH-M model in the basis of daily return on each representative stock market index, which is appropriate to investors' risk-averse preferences. Second, I can also identify the significant asymmetric time-varying volatility originated from the investors' differentiated reactions toward the unexpected market shocks by applying the GJR-GARCH-M model and further find the lasting positive risk aversion coefficient estimators. Third, I derived the negative signs of the regression coefficient of unpredicted volatility on the stock market return by re-applying the GJR-GARCH-M model after I controlled the positive effect of predicted volatility through including the conditional standard deviations from the previous GARCH-M model estimation as an independent explanatory variable in the re-applied new GJR-GARCH-M model. With these consecutive results, the volatility feedback effect was successfully tested to be effective also in the various emerging stock markets, although the leverage hypothesis turned out to be insufficient to be applied to another source of explaining the negative relationship between the unexpected volatility and the ex-post stock market return in the emerging countries in general.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.5
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• pp.189-196
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• 2022

Skyline query is a scheme for exploring objects that are suitable for user preferences based on multiple attributes of objects. Existing skyline queries return search results as batch processing, but the need for real-time search results has increased with the advent of interactive apps or mobile environments. Online algorithm for Skyline improves the return speed of objects to explore preferred objects in real time. However, the object navigation process requires unnecessary navigation time due to repeated comparative operations. This paper proposes a Pre-processing Online Algorithm for Skyline Query (POA) to eliminate unnecessary search time in Online Algorithm exploration techniques and provide the results of skyline queries in real time. Proposed techniques use the concept of range-limiting to existing Online Algorithm to perform pretreatment and then eliminate repetitive rediscovering regions first. POAs showed improvement in standard distributions, bias distributions, positive correlations, and negative correlations of discrete data sets compared to Online Algorithm. The POAs used in this paper improve navigation performance by minimizing comparison targets for Online Algorithm, which will be a new criterion for rapid service to users in the face of increasing use of mobile devices.

• Atmosphere
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• v.34 no.2
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• pp.107-121
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• 2024

In this study, we empirically analyzed the impact of physical risks due to climate change on the soundness and operational performance of the financial industry by combining economics and climatology. Particularly, unlike previous studies, we employed the Seasonal-Trend decomposition using LOESS (STL) method to extract trends of climate-related risk variables and economic-financial variables, conducting a two-stage empirical analysis. In the first stage estimation, we found that the delinquency rate and the Bank for International Settlement (BIS) ratio of commercial banks have significant negative effects on the damage caused by natural disasters, frequency of heavy rainfall, average temperature, and number of typhoons. On the other hand, for insurance companies, the damage from natural disasters, frequency of heavy rainfall, frequency of heavy snowfall, and annual average temperature have significant negative effects on return on assets (ROA) and the risk-based capital ratio (RBC). In the second stage estimation, based on the first stage results, we predicted the soundness and operational performance indicators of commercial banks and insurance companies until 2035. According to the forecast results, the delinquency rate of commercial banks is expected to increase steadily until 2035 under assumption that recent years' trend continues until 2035. It indicates that banks' managerial risk can be seriously worsened from climate change. Also the BIS ratio is expected to decrease which also indicates weakening safety buffer against climate risks over time. Additionally, the ROA of insurance companies is expected to decrease, followed by an increase in the RBC, and then a subsequent decrease.

• Journal of Chest Surgery
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• v.3 no.1
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• pp.31-38
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• 1970

This is a report of three cases of successful embolectomy in peripheral arteries. First case was the patient who received a mitral commissurotomy 8 months ago. In that time, there was no evidence of left atrial thrombosis. He showed an embolism in the middle portion of left brachial artery without complaining of any ischemic pain. Embolectomy was performed 15 days after disappearance of radial pulse and resulted in no return of radial pulse postoperatively. Second case was a case of an embolism in lower portion of right brachial artery. She complained severe ischemic pain and cyanosis in the right forearm and fingers. She was also in the beginning state of cardiac failure, which was suspected from her hypertension associated with cardiomegaly and arrythmia Embolectomy was performed 17 hours after onset of acute pain. Immediate full pulsation of radial artery was obtained after embolectomy and the acute ischemic symptoms subsided gradually. Third case was an embolism in superior mesenteric artery which occured 24 hours after pneumonectomy for right bronchogenic carcinoma and the patient suddenly complained diffuse abdominal colicky pain. 7 hours after attack of abdominal pain. embolectomy with extensive reset ion of the small intestine was performed with uneventful recovery and without complication, such as short bowel syndrome, postoperatively. Histopathologically, the embolus was consisted of a tissue of anaplastic cell carcinoma, which was identical to the tumor of the resected right lung. Histological findings of other emboli of first and second case were old thrombus.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.11
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• pp.1666-1671
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• 1989

A novel switched-capacitor circuit for interfacing capacitive microtransducers with a digital system is developed based on the dual-slope integration. It consists of a differential integrator and a comparator. Driven by the teo phase clock, the circuit first senses the capacitance difference between the transducer and the reference capacitor in the form of charge, and accumulates it into the feedback capabitor of the integrator for a fixed period of time. The resulant accumulated charge is next extracted by the known reference charge until the integrator output voltage refurns to zero. The length of time required for the integrator output to return to zero, as measured by the number of clock cycle gated into a counter is proportional to the capacitance difference, averaged over the integration period. The whole operation is insensitive to the reference voltage and the capacitor values involved in the circuit, Thus the proposed circuit permits an accurate differental capacitance measurement. An error analysis has showh that the resolution as high as 8 bits can be expected by realizing the circuit in a monolithic MOS IC form. Besides the accuracy, it features the small device count integrable onto a small chip area. The circuit is thus particularly suitadble for the on-chip interface.

• International Journal of Costume and Fashion
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• v.8 no.2
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• pp.20-31
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• 2008

A person's external image is a non-verbal form of communication, through which the person's tastes, mode of thought, preferences, and overall personality is expressed. The dominant factor in building an external image is clothing, since clothing-images provide the most information about a person in the least amount of time. This study aims to investigate the relationship between the clothing- images of women politicians and the improvement of women's social status in Korea, by focusing on changes in clothing-image of female politicians at public functions throughout modern Korean history, and inquiring into the method of classification concerning aforementioned images. The time period of this study starts from 1945, when the first female political party was established, to the 2008 presidential elections. The methodology of this study consists of literature study of related books, theses and journals, which was jointly conducted with empirical study consisting of the research of news photographs of major daily newspapers. This study confirmed the clothing images of women politicians since liberation till 2000's reflects the directions of women's movement and their status in return. It is especially meaningful that the sudden increase of romantic and feminine images among the women politician in Korea is the reflection of the ideas of postmodern feminism which emphasize the acknowledgement of womanhood and the enjoyment of being a woman as its core.

• International journal of advanced smart convergence
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• v.8 no.1
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• pp.176-183
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• 2019

Rhyme of Truce is an educational program that helps you develop the ability to cope with cyber violence rightly. we aim to produce educational contents that will last a long time in the memory of specially children. By combining the room escape game and Leap motion / VR, the program reflects the user's motion and action in real time. The Keyboard Worrier comes into contact with the user and causes violence, and the user who is attacked by the monster see several negative messages written in red and hears abuses sound. Users enter the virtual space decorated as the cyber world. They can experience cyber-violence indirectly but vividly, and if language violence, which has been overlooked and recognized only as "letters", is executed offline, it will directly wonder if cyber-violence should also be regarded as a means of violence. Users have the opportunity to cope with violence autonomously. When a user is attacked by an in-game monster, there are two ways to choose from. First, fighting against with a keyboard (which is a symbol of language violence) just like a monster. Second, report the abuser to cyber bureau police. Both methods make them to escape the room, but when they get out of the room and return to the home and read the message through the monitor, users can recognize which action was right for.