• Title/Summary/Keyword: Safety stock

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Financial Security of Vietnamese Businesses and Its Influencing Factors

  • NGUYEN, Van Cong;NGUYEN, Thi Ngoc Lan
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.2
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    • pp.75-87
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    • 2020
  • This paper aims to not only investigate the nature of financial security and its measurement, but also to compare financial security level in 629 listed companies divided into four different industries (materials, industrials, health care, and consumer goods) before building a theoretical framework and regression models to examine the determinants of financial security. By gathering 2,167 financial statements published in Vietnamese Stock Exchange during eight years from 2012 to 2019, with the support of STATA, the research results indicate that six different internal factors, which are liquidity, profitability, firm size, debt management ratios, asset management ratios, and cash flows, explain 77.7% the change of financial security ratio and 3.4% the change in sustainable growth ratio. Specifically, while firm size has a positive impact on sustainable growth ratio but a negative impact on financial security ratio, deb management and profitability have an insignificant influence on the financial security level. Furthermore, an increase in asset management ratios would result positively in both two dependent variables whereas a rise in sustainable growth and a decline in financial security ratio are expected to witness if there is an increase in cash flows.

Communication Consecutive Test of Train Oriented Control System for Wayside Equipment Control (선로변 시설물 차상제어를 위한 차상중심 열차제어시스템의 통신 연속성 시험)

  • Baek, Jong-Hyen
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.5
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    • pp.703-712
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    • 2014
  • To improve the efficiency and safety of railway systems, the train control system has been considerably evolved from the ground-equipment-based control system (e.g. track circuit, interlocking system, etc.) into the on-board-equipment-based control system. In addition, this train control system enables the rolling stock to intelligently control the trackside facilities by introducing the information and communication technologies (ICT). Accordingly, since the ICT-based train control system makes the railway system be simplified (i.e. the heavy ground-equipment can be removed), the efficient and cost-effective railway system can be realized. In this paper, we perform the feasibility test of the ICT-based train control system via a simulation. To this end, we have developed the prototypes of the on-board controller and wayside object control units which control the point and crossing gate and performed the integrated operation simulation in a testbed. In this paper, before the field test of the on-board-controller-based train control system, we perform the Consecutive operation test for prototypes of the on-board controller, wayside object control units and local control computer.

Determination of Maintenance Period Considering Reliability Function and Mission Reliability of Electromagnetic Valves of EMU Doors Considering Air Leakage Failure (전동차 출입문 전자변 누기고장의 신뢰도 함수와 임무 신뢰도를 고려한 정비 주기 결정)

  • Park, Heuiseop;Koo, Jeongseo;Kim, Gildong
    • Journal of the Korean Society for Railway
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    • v.20 no.5
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    • pp.569-576
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    • 2017
  • The electromagnetic valve of pneumatic doors of EMUs has a high failure rate due to air leakage because it supplies air on and off to operate the doors repeatedly. The electromagnetic valve is a very important safety component for which a very high reliability is required because failure makes it impossible to operate the passenger cars. However, domestic urban railway operators maintain electronic valves of the EMU door under a fixed cycle with a spare period according to the full overhaul cycle of the EMU. An improvement of the current maintenance cycle was suggested based on the reliability function and mission reliability. Using the statistical program MINITAB for the operational data of EMU line 6, we analyzed the characteristics of the fault distribution and derived the shape and scale parameters of the reliability function. If we limit the specific reliability probability to under a certain failure rate and calculate its statistical parameters, we can calculate the allowable inspection period with mission reliability. Through this study, we suggested a maintenance period based on RCM (reliability centered-maintenance) to improve the reliability of electromagnetic valves from 68% to 95%.

Estimation of Measurement Uncertainty for the HPLC Analysis of Deoxynivalenol in Wheat (밀에서 HPLC에 의한 데옥시니발레놀 분석의 측정불확도 산정)

  • Ok, Hyun-Ee;Chang, Hyun-Joo;Ahn, Jang-Hyuk;Cho, Jae-Young;Chun, Hyang-Sook
    • Korean Journal of Food Science and Technology
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    • v.41 no.3
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    • pp.258-264
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    • 2009
  • The principal objective of this study was to estimate the measurement uncertainty associated with determination of deoxynivalenol (DON), a mycotoxin generated by Fusarium strain, in food. In service of this goal, wheat as a food matrix was analyzed via high performance liquid chromatography-ultraviolet (HPLC-UV) detection using an immunoaffinity column for clean-up. The uncertainty sources in the measurement process were identified by sample weight, final volume, and sample concentration in extraction volume with components including standard stock solution, working standard solution, 5 standard solutions, calibration curve, matrix, and instrument. The expanded uncertainty for DON at a concentration of 300 ${\mu}g/kg$ was estimated as 71.62 ${\mu}g/kg$ using a coverage factor of two, which provides a confidence level of approximately 95%. The most influential component in the uncertainty sources was the recovery of the wheat matrix, followed by the calibration curve. These results indicate that all efforts may be directed toward reducing the uncertainties of the recovery of the wheat matrix and the calibration curve to obtain a reliable HPLC-UV method for DON analysis in wheat.

Analysis of Medroxyprogesterone Acetate in Meats (유통 식육 중 성장호르몬제 초산메드록시프로게스테론의 분석)

  • Lee, Yoon-Ae;Shim, Jee-Youn;Lee, Ryun-Kyung;Kim, Seung-Hwan;Oh, Hyun-Sook;Cho, Tae-Yong
    • Journal of Food Hygiene and Safety
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    • v.25 no.3
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    • pp.226-231
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    • 2010
  • We aimed at the monitoring medroxyprogesterone acetate (MPA) residue amount in meats and confirmed the safety of its residue in meats. Optimized condition for analytical and instrumental methods was obtained by method validation. The limit of detection (LOD) and limit of quantification (LOQ) were validated at 1.5 and 5.0 ug/kg, respectively. The calibration curve showed good linearity ($r^2$ = 0.9968) within the concentration range of 5.0~50.0 ug/kg. We selected progesterone-d9 for internal standard, The recoveries in fortified meat ranged from 67.5 to 109.56% at the 3 spiking levels. As the regulation of MPA analysis method used by LC-MS/MS on other products have established. We selected 3 species of farm stock products (cattle, pig, chicken) and purchased at the markets of seven major cities. The total 196 of meat including 46 of domestic beef, 43 of import beef, 60 of domestic pork, 12 of import pork and 35 of domestic chicken. No residue of synthetic growth hormones were detected in cattle, pig and chicken samples tested.

Single Laboratory Validation and Uncertainty Estimation of a HPLC Analysis Method for Deoxynivalenol in Noodles (면류에서 HPLC를 이용한 데옥시니발레놀 분석법의 검증과 불확도 산정)

  • Ee, Ok-Hyun;Chang, Hyun-Joo;Kang, Young-Woon;Kim, Mee-Hye;Chun, Hyang-Sook
    • Journal of Food Hygiene and Safety
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    • v.26 no.2
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    • pp.142-149
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    • 2011
  • An isocratic high performance liquid chromatography (HPLC) method for routine analysis of deoxynivalenol in noodles was validated and estimated the measurement uncertainty. Noodles (dried noodle and ramyeon) were analyzed by HPLC-ultraviolet detection using immunoaffinity column for clean-up. The limits of detection (LOD) and quantification (LOQ) were 7.5 ${\mu}g$/kg and 18.8 ${\mu}g$/kg, respectively. The calibration curve showed a good linearity, with correlation coefficients $r^2$ of 0.9999 in the concentration range from 20 to 500 ${\mu}g$/kg. Recoveries and Repeatabilities expressed as coefficients of variation (CV) spiked with 200 and 500 ${\mu}g$/kg were $82{\pm}2.7%$ and $87{\pm}1.3%$% in dried noodle, and $97{\pm}1.6%$ and $91{\pm}12.0%$ in ramyeon, respectively. The uncertainty sources in measurement process were identified as sample weight, final volume, and sample concentration in extraction volume as well as components such as standard stock solution, working standard solution, 5 standard solutions, calibration curve, matrix, and instrument. Deoxynivalenol concentration and expanded uncertainty in two matrixes spiked with 200 ${\mu}g$/kg and 500 ${\mu}g$/kg were estimated to be $163.8{\pm}52.1$ and $435.2{\pm}91.6\;{\mu}g$/kg for dried noodle, and $194.3{\pm}33.0$ and $453.2{\pm}91.1\;{\mu}g$/kg for ramyeon using a coverage factor of two which gives a level of statistical confidence with approximately 95%. The most influential component among uncertainty sources was the recovery of matrix, followed by calibration curve.

A Study on Industries's Leading at the Stock Market in Korea - Gradual Diffusion of Information and Cross-Asset Return Predictability- (산업의 주식시장 선행성에 관한 실증분석 - 자산간 수익률 예측 가능성 -)

  • Kim Jong-Kwon
    • Proceedings of the Safety Management and Science Conference
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    • 2004.11a
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    • pp.355-380
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    • 2004
  • I test the hypothesis that the gradual diffusion of information across asset markets leads to cross-asset return predictability in Korea. Using thirty-six industry portfolios and the broad market index as our test assets, I establish several key results. First, a number of industries such as semiconductor, electronics, metal, and petroleum lead the stock market by up to one month. In contrast, the market, which is widely followed, only leads a few industries. Importantly, an industry's ability to lead the market is correlated with its propensity to forecast various indicators of economic activity such as industrial production growth. Consistent with our hypothesis, these findings indicate that the market reacts with a delay to information in industry returns about its fundamentals because information diffuses only gradually across asset markets. Traditional theories of asset pricing assume that investors have unlimited information-processing capacity. However, this assumption does not hold for many traders, even the most sophisticated ones. Many economists recognize that investors are better characterized as being only boundedly rational(see Shiller(2000), Sims(2201)). Even from casual observation, few traders can pay attention to all sources of information much less understand their impact on the prices of assets that they trade. Indeed, a large literature in psychology documents the extent to which even attention is a precious cognitive resource(see, eg., Kahneman(1973), Nisbett and Ross(1980), Fiske and Taylor(1991)). A number of papers have explored the implications of limited information- processing capacity for asset prices. I will review this literature in Section II. For instance, Merton(1987) develops a static model of multiple stocks in which investors only have information about a limited number of stocks and only trade those that they have information about. Related models of limited market participation include brennan(1975) and Allen and Gale(1994). As a result, stocks that are less recognized by investors have a smaller investor base(neglected stocks) and trade at a greater discount because of limited risk sharing. More recently, Hong and Stein(1999) develop a dynamic model of a single asset in which information gradually diffuses across the investment public and investors are unable to perform the rational expectations trick of extracting information from prices. Hong and Stein(1999). My hypothesis is that the gradual diffusion of information across asset markets leads to cross-asset return predictability. This hypothesis relies on two key assumptions. The first is that valuable information that originates in one asset reaches investors in other markets only with a lag, i.e. news travels slowly across markets. The second assumption is that because of limited information-processing capacity, many (though not necessarily all) investors may not pay attention or be able to extract the information from the asset prices of markets that they do not participate in. These two assumptions taken together leads to cross-asset return predictability. My hypothesis would appear to be a very plausible one for a few reasons. To begin with, as pointed out by Merton(1987) and the subsequent literature on segmented markets and limited market participation, few investors trade all assets. Put another way, limited participation is a pervasive feature of financial markets. Indeed, even among equity money managers, there is specialization along industries such as sector or market timing funds. Some reasons for this limited market participation include tax, regulatory or liquidity constraints. More plausibly, investors have to specialize because they have their hands full trying to understand the markets that they do participate in

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A study on the applicability of newly developed stainless steel for weight reduction of carbody of intermodal tram (인터모달 트램 차체 경량화를 위한 신개발 스테인레스 강재 적용성 연구)

  • Seo, Sung-il;Kim, Jeong-guk;Jung, Hyun-seung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.3
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    • pp.457-463
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    • 2016
  • The newly developed super ductile duplex stainless steel (SDSS) has good strength and ductility, and it can be used to reduce weight and improve the fabrication efficiency of a carbody of a rolling stock. In this study, spot weldability tests were conducted to take advantage of SDDSS in a carbody for an intermodal tram. Specimens of various thickness (0.4 to 5.0 mm) were prepared to find the proper welding conditions, and tensile load tests were conducted to evaluate the tensile-shear strength of spot welded joints. Then, nugget diameters were measured to verify the quality. The tensile-shear strength was found to be proportional to the heat parameter. It was verified that the tensile-shear strengths and nugget sizes of the joints satisfy the standard requirements. The overall weldability tests confirmed that SDDSS can be used effectively for the carbody of an intermodal tram.

Review and Suggestion for Waste Transfer Stations in Seoul (서울시 생활폐기물 적환장 운영실태 분석 및 제언)

  • Yoo, Kee-Young
    • Journal of the Korea Organic Resources Recycling Association
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    • v.24 no.4
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    • pp.21-29
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    • 2016
  • This study was conducted to review Waste Transfer Stations(WTSs) in Seoul, especially focusing on three aspects, main roles, neighbor friendly and regulation compliance, and to draw out recommendation for improvement. The 46 units of all 65 WTSs treated large amount of waste on a day shipping-out schedule, the other 19 WTSs treated small amounts of wastes which were transported after 3~30 days stock. About 57% of WTSs are located in residential or commercial area. Other 57% of WTSs were open without walls. 79% of WTSs were placed alone. Just 17% of WTSs were permitted as environmental infrastructures by urban planning law, and 31% of WTSs were operated by private waste haulers who were permitted by waste management law. Most WTSs in Seoul seemed to go well with on-going policy demand, such as regionalizing waste treatment facilities, expanding waste recycling, and so on. However lots of WTSs did not implement sufficient environmental protection measures, and partly not compliant with regulations related to urban infrastructures. In the future, the issue on sealing facilities and integrating functions of waste management facilities could be considered in order to fit in urban environment.

An Implementation of Smart Card Identification System Using 1 vs. 1 Fingerprint Matching (1대1 지문매칭을 이용한 스마트 카드 인증 시스템의 구현)

  • 최순우;김영길
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.5 no.7
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    • pp.1204-1209
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    • 2001
  • According to the rapid development of information and communication, various services are offered using information and communication infrastructure for example e-commerce, internet banking, stock dealings, etc. This time, the most important problem is personal identification. But now secret number that is used to personal identification mostly can be misappropriated. To solve this problem, this paper proposes smart card identification system using 1 vs. 1 fingerprint matching. Information protection and security of smart card excel and use is convenient. And fingerprint becomes the focus of public attention in biometric field. Implemented system in this paper is based on PC. This system stores minutia that is fingerprint information into smart card and compare it with personal minutia. Therefore this system is sure to be on personal identification. If this system is applied to various services, safety degree of services will be enhanced.

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