• 한국유통학회지:유통연구
• /
• 제7권1호
• /
• pp.41-59
• /
• 2002

본 연구는 제품의 영업환경에 따라 공급체인구조가 어떻게 달라지는가에 대하여 실증적으로 분석한 것으로서 환경과 공급체인구조에 있어 기존의 논의대상인 기업(business)수준이 아닌 제품 단위에서 공급체인구조에 대한 분석이 이루어 졌다. 이는 기업내 각각의 제품에 따라 제품특성별로 공급체인관리가 이루어져야 하는 중요성을 인식할 때 통합적 공급체인관리에 있어 제품단위의 분석은 필수적이라 할 수 있다. 이에 연구목적을 달성하기 위해 제품환경을 특성에 따라 분류해 공급체인 구조와의 관계를 연구하였다. 여기서 공급체인 구조변수는 기존 문헌연구를 통해 도출하였다. 본 실증 연구를 위하여 제품별 공급체인에 대한 설문조사를 실시하였으며, 통계방법은 주로 분산분석(ANOVA)을 사용하였다. 연구 결과를 요약하면, 제품 영업환경과 공급체인구조간의 관련성을 분석한 결과, 제품의 영업환경에 따라 공급체인구조가 달라짐을 보였다. 제품영업환경의 두집단, 즉 불확실한 제품환경집단과 안정된 제품환경집단에 따라 공급체인 구조변수(공급체인 참여자수, 공급체인리드타임, 관리적 독립성, 공급체인의 대응점)의 관계에 있어서는 공급체인 참여자수를 제외한 모든 구조변수에서 모두 유의미한 관계를 나타내었다. 공급체인의 구조변수에서 공급체인의 길이를 나타내는 변수로는 공급체인의 참여자수와 공급체인 리드타임이며, 공급체인에 대한 모니터링이나 트러스트 측면을 나타내는 변수로는 관리적 독립성과 공급체인의 대응점이다. 분석결과 환경이 불확실한 제품의 경우 공급체인의 길이측면에서는 안정된 제품보다 짧게 나타나고 있고 공급체인에 대한 모니터링이나 트러스트 측면에서는 환경이 불확실한 제품이 안정된 제품보다 활발히 이루어지고 있는 것으로 나타났다. 따라서 영업환경이 불확실한 제품의 경우 공급체인 구조를 디자인함에 있어서 시장(market)보다는 위계 (hierarchy)위주의 관리에 주안점을 두고 있음을 보여주고 있으며, 반면 영업환경이 안정된 제품의 경우에는 시장 (market)위주의 관리 방식에 초점을 두고 있는 것으로 나타났다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제50권12호
• /
• pp.624-630
• /
• 2001

The trend of the regulations on environmental issues are getting tight. Responding to this trend new technologies such as moving electrodes, wide pitch and pulsed power supply are also introduced in the electrostatic precipitator(EP) systems. The introduction of wide pitch and moving electrodes enhances the system performance of the EPs by improving air-flow and by improving the ash reentrainment on rapping. The power supplies for the EPs developed up to date include thyristor-based dc or intermittent type, SMPS(switching mode power supply) type and the pulsed-power supply type. The use of the pulsed ones is known to improve dust-collecting efficiency of high resistivity ash and reduces back corona occurrence in the collecting plate. There are two kinds of pulsed-power supplies; one with pulsed transformers and the other with direct dc switching devices. The latter uses rotary spark gap switches or semiconductor switches. Both have the merits and demerits: the spark gap switches are simple and robust but has short life time, hence, high maintenance cost, whereas the semiconductor switches have long life time but are costly. In this study, A high voltage power supply with superimposing voltage pulse on dc source was developed for EPs. This study describes circuit topology, operating principle of the scheme, and analysis of experimental results on Dong-Hae Power Plant. The pulsed power supply consists of a variable dc power supply with ratings of 60kV, 800mA and pulse generator which is made of high voltage thyristor-diode switch strings, an LC resonant tank and a blocking inductor. The pulse generator generates variable pulse-voltage up to 70kV using a high frequency resonant inverter with a variable dc source. Two prototypes were built and tested on 250MW DongHae power plant to verify the possibility of the commercial use and the normal operation in the transient states.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 추계학술대회
• /
• pp.484-489
• /
• 2003

The mass flow rate of gas flow through critical nozzle depends on the nozzle supply conditions and the cross-sectional area at the nozzle throat. In order that the critical nozzle can be operated at a wide range of supply conditions, the nozzle throat diameter should be controlled to change the flow passage area. This can be achieved by means of a variable critical nozzle. In the present study, both experimental and computational works are performed to develop variable critical nozzle. A cone-cylinder with a diameter of d is inserted into conventional critical nozzle. It can move both upstream and downstream, thereby changing the cross-sectional area of the nozzle throat. Computational work using the axisymmetric, compressible Navier-Stokes equations is carried out to simulate the variable critical nozzle flow. An experiment is performed to measure the mass flow rate through variable critical nozzle. The present computational results are in close agreement with measured ones. The boundary layer displacement and momentum thickness are given as a function of Reynolds number. An empirical equation is obtained to predict the discharge coefficient of variable critical nozzle.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제16권5호
• /
• pp.615-623
• /
• 2016

The paper describes a hysteretic buck converter including a differentiator and an adaptive hysteresis window controller. Differentiating the feedback signal achieves ultra-fast switching of the buck converter. The adaptive hysteresis window control allows a monotonous operation with predictable noise spectrum, and gives way to efficient design for variable supply and output voltages. The measurement results in a $0.13-{\mu}m$ CMOS process indicated that the switching frequency became double times higher, and the voltage ripple was reduced by up to 69%. They also indicated that the normalized switching frequency variation was reduced by 74% with variable $V_{DD}$ and by 63% with variable $V_{OUT}$. The power efficiency was improved by 3.5% depending on loading condition.

• Asian-Australasian Journal of Animal Sciences
• /
• 제21권10호
• /
• pp.1435-1440
• /
• 2008

An experiment was carried out to investigate whether a local breed of cattle is better adapted than European breed crosses to low quality feeds and to variations in their supply. Four Red Chittagong (RC) and four Holstein cross Sahiwal (Hx) cattle were used to compare the intake and digestibility of German grass (Echinocloa crusgalli) and rice straw with four regimes of feed supply. These were; a choice of German grass and rice straw each offered ad libitum on the same day (A); German grass and rice straw offered ad libitum on alternate days (B); rice straw offered ad libitum for 5 days followed by German grass ad libitum for 5 days (C); and German grass offered ad libitum for 5 days followed by rice straw ad libitum for 5 days (D). Each breed was offered the treatments in a $4{\times}4$ Latin Square design. The German grass intake and total dry matter intake per kg metabolic live weight were significantly higher for the Hx than for RC, but there were no significant effects of genotype on digestibility of nutrients or live weight. Treatment A had the highest proportion of German grass relative to rice straw in the total DM intake, and had the highest total DM intake and apparent digestibility of nutrients compared with treatments B, C and D. It was concluded that there was no significant evidence that the RG cattle were better adapted to a variable supply of low quality feed than Hx cattle, and that the variable feed supply reduced the ability of cattle to select a preferred diet and consequently nutrient intake was depressed.

• 한국ITS학회 논문지
• /
• 제10권1호
• /
• pp.16-26
• /
• 2011

가변속도제어(Variable Speed Limit ; VSL)는 교통상황에 따라 속도를 차등 제한하여 혼잡 또는 사고지점에 도달하기전 차량간, 차로간 속도편차를 감소시킴으로써 사고를 예방하고 총 지체를 최소화하기 위한 연속류 ITS기법 중 하나이다. 본 연구에서는 가변속도 제어시 연속류 기본구간의 동적교통류에 대한 수학적 분석결과를 기초로 가변속도제어 수행모형을 제시하고 효과분석을 수행하였다. 가변속도제어모형은 병목현상 발생시 상류부에 전파되는 충격파의 속도를 최소화 함으로써 지체를 감소시킬 수 있도록 graphical solution을 적용하여 제시한다. 또한 가변속도 제어시 해당 지점으로부터 하류부로 전파되는 충격파의 생성 및 움직임을 모형화 하여 재현하며 그 방법론으로는 Cell-Transmission Model 및 Supply-Demand Method를 적용하였다. 가변속도제어 적용에 따른 효과분석으로는 제어를 통한 지체감소의 효용성 및 안전도 측면에서 각 Cell별 속도 및 밀도의 표준편차의 개선정도를 살펴보았다. 향후 본 연구의 이론적 검증 및 분석 결과를 토대로 다양한 가변속도제어모형 및 운영방안을 개발할 수 있을 것으로 예상한다.

• 상하수도학회지
• /
• 제19권4호
• /
• pp.395-403
• /
• 2005

It is very important to forecast water supply for reasonal operation and management of water utilities. In this paper, water supply forecasting models using artificial intelligence are developed. Artificial intelligence models shows better results by using Temperature(t), water supply discharge (t-1) and water supply discharge (t-2), which are expressed by neural network(LMNNWS; Levenberg-Marquardt Neural Network for Water Supply, MDNNWS; MoDular Neural Network for Water Supply) and neuro fuzzy(ANASWS; Adaptive Neuro-Fuzzy Inference Systems for Water Supply). ANFISWS model which is applied for water supply forecasting shows stable application to the variable water supply data. As results, MDNNWS model shows the highest overall accuracy among proposed water supply forecasting models and the lowest estimation error with the order of ANFISWS, LMNNWS model.

• 유통과학연구
• /
• 제20권11호
• /
• pp.79-88
• /
• 2022

Purpose: The purpose of this study was to determine the effect of agricultural exports and imports on economic growth in Bangladesh and propose an upgraded and customized model of the supply chain for agribusiness growth in Bangladesh to achieve plain sailing and systematic operation and financial gains at home and abroad. Research design, data, and methodology: All data in the research have been collected from secondary sources. Gross domestic product was used as the dependent variable and exports and imports of agricultural products were used as independent variables. Pairwise Granger causality was utilized to see the impact of the variable responsible for the economic growth in Bangladesh and the causal relationship between the variables analyzed was measured using Johansen co-integration test. Results: From the empirical analysis, the researchers observed that agricultural commodity imports and exports have a unidirectional impact on economic growth in Bangladesh and a long-run causal link with economic growth in Bangladesh. The suggested supply chain model of agribusiness aids in achieving smooth operations, systematic management, and monetary gains both domestically and internationally. Conclusions: This paper contributes to the development of a more effective and profitable agribusiness supply chain in Bangladesh systematically through their theoretical and practical implications.

• The Journal of Asian Finance, Economics and Business
• /
• 제10권1호
• /
• pp.9-17
• /
• 2023

The study attempted to answer the questions related to the expected effects of supply chain management variables which include: Partnership with Suppliers (PS), Relationships with Customers (RC), Quality of Information Exchange (QIE), and Postponement (P), as independent variables, total quality management (TQM) as a dependents variable, and just in time (JIT) as a mediator variable. The study relies on the descriptive approach by conducting an empirical study on commercial companies in Riyadh Governorate in the Kingdom of Saudi Arabia. Through the methods of descriptive and analytical statistics represented in exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and structural equation modeling (SEM)), using the AMOS and SPSS programs, the results of the applied study indicated that: There is an effect of supply chain management variables (quality of information exchange, Postponement) on just in time (JIT), there is no effect of the supply chain variables (relationship with customers, partnership with suppliers) on just in time (JIT), there is an indirect effect of the quality of information exchange, Postponement, partnership with suppliers, the relationship with customers on total quality management (TQM), relationship with customers affect on total quality management (TQM) indirectly, just in time (JIT) does not affect total quality management (TQM)

• 한국산학기술학회논문지
• /
• 제7권1호
• /
• pp.21-26
• /
• 2006

수요전원의 전압, 전류의 가변 용이성을 높이기 위해 조종부를 디지털로 구현하고, 또한 원격의 시스템이 요구하는 변동 전원이 있는 경우, 원거리 집중 조작과 감시를 위한 PC통신(RS-232C)이 가능하게 하여 안정적인 전원공급이 가능하게 하였다. 또한 입력전력에 대한 출력전력의 고 효율을 실현하는데 목표를 두고 있다. 이는 송전 선로의 용량 부족과 옥외 옥내 배선의 용량부족 등의 부하변동으로 인해 전압의 변동률이 높은 우리나라에서 유용하게 사용될 수 있을 것이다.