• 전력전자학회논문지
• /
• 제3권4호
• /
• pp.330-337
• /
• 1998

히스테리시스 제어를 사용하는 Buck 컨버터의 평균모델을 위한 Duty Cycle 모델이 수학적으로 구해진다. 이 모델은 시간영역에서 연속 전도 모드와 불연속 전도 모드 모두를 동시에 시물레이션할 수 있다. 또한, SABER의 MAST언어를 이용하여, 제안된 모델의 템플릿이 제시되며, 이 템플릿은 시간영역이나 주파수 영역의 해석을 위해 사용되어질 수 있다. 이 템플릿의 정확성을 컴퓨터 시뮬레이션을 통하여 증명한다.

• East Asian Economic Review
• /
• 제21권1호
• /
• pp.3-27
• /
• 2017

This paper studied the effects of anti-dumping measures on the imports to investigate whether the trade restriction effect of an anti-dumping duty is dominant. Our results indicate that a 1% increase in the anti-dumping duties decreases the import of the targeted product by about 0.43~0.51%. The actual statistics, however, show that the total import of the targeted products increased by about 30 percent while an anti-dumping duty was in force. That indicates that an anti-dumping duty is just a temporary import relief. This paper also investigated whether an anti-dumping duty is terminated in the case that the injury would not be likely to continue or recur if the duty were removed. The hazards model estimates show that increase in market share, MFN tariff rate, and dumping margin decrease the hazard of termination of an anti-dumping duty, but the increase in value added increases the hazard of termination. Generally speaking, this result indicates that the WTO member countries have regulated the overuse of an anti-dumping measure. The findings of this paper show that there is a country- and industry-wise heterogeneous characteristic in the effect as well as termination of an anti-dumping duty.

• 한국기계가공학회지
• /
• 제6권2호
• /
• pp.59-66
• /
• 2007

Voice coil actuator is used linear motion system that requires precision positioning control. In order to control precision positioning of voice coil actuator, relation model between duty ratio and moving displacement of voice coil actuator is needed. This paper present a duty ratio - displacement model in PWM control of voice coil actuator. Transfer function of voice coil actuator is obtained by combining voice coil motor's equation of motion with the equation of circuit and characteristic of voice coil motor. Consider to initial condition of velocity and current, transfer function is transformed mathematical model. The induced model can predict output displacement, velocity and current according to duty ratio and amplitude. The model is verified by experimental tests such as velocity and displacement response of voice coil motor. Simulated results have tracking errors of less than 10 percent of experimental results.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회A
• /
• pp.602-607
• /
• 2007

The heavy duty diesel engine must have a large output for maintaining excellent mobility. The compacted graphite iron (CGI) is a material currently under study for the engine demanded for high torque, durability, stiffness and fatigue. In this study, three dimensional finite element model of a heavy-duty diesel engine was developed to conduct the stress analysis by using property of CGI. The FE model of the heavy duty diesel engine section consisting with four half cylinder was selected. The heavy duty diesel engine section include cylinder block, cylinder head, liner, bearing cap, bearing and bolt. The loading conditions of engine are pre-fit load, assembly force and gas force.

• 한국항공운항학회지
• /
• 제23권4호
• /
• pp.73-81
• /
• 2015

The purpose of this study is to explore structural relationship between cognitive factors and emotional factors in predicting behavioral intention of duty-free users. This study conducted questionnaire survey on 246 users of duty-free shops and analyzed it by using structural equation. As the result of the study, attitude was significantly associated with both desire and behavioral intention. Subjective norm had a significant impact on desire, but had no significant imfact on behavioral intention. Whereas perceived behavioral control did not have a significant influence on desire and intention. Desire, which plays mediating role as a major variable in goal-directed behavioral model, turned out to not only have significant impact on behavioral intention but has the strongest effect as well. This study has its academic meaning in that it explored factors which have effect on decision-making process of duty-free users focusing on goal-oriented behavioral model, which is one of integrated psychological models. In practical terms, this study can be used as a basic material for corporations to establish goals in domestic duty-free shops.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2004년도 ICCAS
• /
• pp.1350-1354
• /
• 2004

This paper proposes a simple but practically useful model for preventing fraud of users called "ERBAC03". The new model consists of qualified mandatory and discretionary features for roles and locations, including the assignment of permissions for the appropriate roles and the assignment of roles for the appropriate locations. Moreover, a static separation of duty (SSoD) principle is applied to the new model for integrity requirements of security systems. The paper also explores some extensions of ERBAC03 including the new model using the SSoD concept from some experiments. The experimental results prove the efficiency improvement of the proposed model that can make benefits for large enterprises.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제16권6호
• /
• pp.1849-1876
• /
• 2022

Wireless Sensor Network (WSN) is considered as an integral part of the Internet of Things (IoT) for collecting real-time data from the site having many applications in industry 4.0 and smart cities. The task of nodes is to sense the environment and send the relevant information over the internet. Though this task seems very straightforward but it is vulnerable to certain issues like energy consumption, delay, throughput, etc. To efficiently address these issues, this work develops a cross-layer model for the optimization between MAC and the Network layer of the OSI model for WSN. A high value of duty cycle for nodes is selected to control the delay and further enhances data transmission reliability. A node measurement prediction system based on the Kalman filter has been introduced, which uses the constraint based on covariance value to decide the scheduling scheme of the nodes. The concept of duty cycle for node scheduling is employed with a greedy data forwarding scheme. The proposed Duty Cycle-based Greedy Routing (DCGR) scheme aims to minimize the hop count, thereby mitigating the energy consumption rate. The proposed algorithm is tested using a real-world wastewater treatment dataset. The proposed method marks an 87.5% increase in the energy efficiency and reduction in the network latency by 61% when validated with other similar pre-existing schemes.

• 대한기계학회논문집A
• /
• 제32권5호
• /
• pp.402-410
• /
• 2008

The heavy duty diesel engine must have a large output for maintaining excellent mobility. In this study, a three dimensional finite element model of a heavy-duty diesel engine was developed to conduct the stress analysis. The FE model of the heavy duty diesel engine main parts consisting with four half cylinder was selected. The heavy duty diesel engine parts includes with cylinder block, cylinder head, gasket, liner, bearing cap, bearing and bolts. The loading conditions of engine were pre-fit load, assembly load, and gas load. As the results of structural analysis, because the stress values of cylinder block and bearing cap did not exceed the basic design can be satisfied. But on the part which contacts with cylinder block and bearing cap the stress value exceeds the allowable strength of material. In order to decrease the stress at that part, it was optimized with parametric study.

• 한국컴퓨터정보학회논문지
• /
• 제15권11호
• /
• pp.233-239
• /
• 2010

본 연구는 노인복지시설 종사자 재직기간에 따른 직무요인, 조직성과의 모형정립에 관해 연구하는 것을 목적으로 한다. 이론적 배경에서 노인복지시설에 관한 문헌 검토와 노인복지시설 종사자의 직무요인 및 조직성과에 대한 제이론을 검토하였다. 이론을 근거로 실증적 자료의 분석을 통하여 노인복지시설 종사자의 직무요인이 조직성과에 미치는 인과관계의 영향요인에 대한 재직기간의 조절효과를 검증하고자 한다. 노인복지시설 종사자의 직무요인인 보수, 승진, 조직풍토, 업무환경, 조직구조가 조직성과인 직무만족과 조직몰입 및 충성도에 개인특성요인인 재직기간에 따라 다르게 영향을 미칠 것으로 가정한다. 실증적 분석에서는 연구대상에 대한 인구통계학적 분석과 연구모형에 대한 적합도를 검증하며, 구조방정식모형을 통해 가설검증과 조절효과 분석을 실행하고자 한다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2004년도 ICCAS
• /
• pp.1360-1364
• /
• 2004

This paper propose an extended model for role-permission assignment based on locations called "Enhanced Role-Based Access Control (ERBAC03)". The proposed model is built upon the well-known RBAC model. Assigning permissions to role is considered too complex activity to accomplish directly. Instead we advocate breaking down this process into a number of steps. The concept of jobs and tasks is specifically introduced to facilitate role-permission assignment into a series of smaller steps. This model is suitable for any large organization that has many branches. Each branch consists of many users who work in difference roles. An administration tool has been developed to assist administrators with the administration of separation of duty requirements. It demonstrates how the specification of static requirements can be done based on "conflicting entities" paradigm. Static separation of duty requirements must be enforced in the administration environment. Finally, we illustrate how the ERBAC03 prototype is used to administer the separation of duty requirements.