• Journal of international Conference on Electrical Machines and Systems
• /
• v.2 no.3
• /
• pp.269-274
• /
• 2013

Fault-tolerant capability, wide speed range and overload capability are required in electric motors used in electric vehicles. In this paper, based on the analysis of the all poles wound and alternate poles wound flux-switching permanent-magnet machines, an optimization method is studied to reduce torque ripple. The method takes account of both flux-leakage and cogging torque. The simulation result shows that the method can reduce the torque ripple effectively. This study lays the foundation for the further application of FSPM in electric vehicles.

• Proceedings of the KIEE Conference
• /
• 1999.07c
• /
• pp.1023-1025
• /
• 1999

This paper provides the steady-state UPFC model referred as UPFC injection model for power flow control. The application of UPFC for the line overload alleviation is demonstrated through a numerical example. It is shown that UPFC has the capability of regulating the power flow, therefore alleviating the line overload.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.8 no.3
• /
• pp.87-95
• /
• 2012

Up to now, industrial cranes play important roles as the effective machines to carry heavy loads in the manufacturing premise, in the construction field and so on. And, a crane is widely used not only to daily work but also to carry heavy materials efficiently in a construction site for prevention of accident. However, the crane operation is highly complicated even for experts. In this paper, we developed the content of the crane mounted on the controller. This content overload conditions in the operating environment for the crane operator to warn, and the operation of equipment has the capability to limit automatically. The content for crane controller is to alert the operator overload and to limit the operation of equipment for stabilizing capabilities. The content of the flexible algorithm is based on stabilizing controllers, PLC (Programmable Logic Controller) to connect for using the equipment and electrical control systems to ensure the safety of workers and to improve the ability to work possible.

• ETRI Journal
• /
• v.20 no.2
• /
• pp.115-132
• /
• 1998

This paper proposes an extended service filtering technique to prevent overload in service control point (SCP) due to televoting (VOT) or mass calling (MAS) services with the heavy traffic characteristics. Also, this paper compares this extended technique with the existing overload control techniques, and calculates steady state call blocking probabilities in intelligent network (IN) under overload conditions. The proposed technique considers SCP overload and IN Capability Set (CS)-1 services (such as VOT or MAS service) that have to use the specialized resources of intelligent peripheral (IP). This technique uses first an activating step in which SCP requests service filtering to service switching point (SSP). Then, in the filtering step, SSP sends filtering results to SCP periodically or each N-calls. Also, when filtering time-out expires, SSP stops service filtering, and sends service filtering response to SCP in the deactivating step. This paper applies this technique to VOT/MAS service, and calculates SCP and SSP-IP (circuit) call blocking probabilities by using an analytical VOT/MAS service model. With the modeling and analyzing of this new technique, it shows that this technique reduces the traffic flow into SCP from SSP and IP prominently.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.3
• /
• pp.1046-1052
• /
• 2017

The load on the power grid of South Korea is expected to grow continuously until the late 2020s, and it is necessary to increase the transfer capacity from the Eastern grid to the Seoul-Gyeonggi region by reinforcing the transmission network for the electric power system to remain stable. To this end, the grid reinforcement by two bipole LCC HVDC transmission systems have been considered on account of the public acceptability and high growth of the fault current level, even though an additional 765kV system construction is more economical. Since the probability of the existing 765kV double circuit transmission line trip is extremely low, a dynamic simulation study was carried out to estimate the efficient HVDC capacity able to stabilize the transient stability by utilizing the HVDC overload capability. This paper suggests the application plan to reduce the HVDC construction capacity with ensuring the transient stability during the 765kV line trip.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.36 no.4
• /
• pp.231-239
• /
• 1987

Distribution system is one of large and complicated sytem, consisted of a great number of components. Therefore efficient operation based on precise analysis and computation methods is indispensable accommodating growing loads. This paper describes an optimal operation problem to relieve overload flow in radial distribution systems by using modified block model. The problem is formulated as a network problem of synthesizing the optimal spanning tree in a graph, branch and bound method is used for the optimization. Especially modified block model proposed in this paper is validated more practical than conventional model. These methods can be applied to two types of distribution system problems such as, 1) planning problem to check the capability of relieving overload at normal rating, 2) emergency operation problem to determine switching scheme for minimizing customer loads affected by a fault. Examples of application to these problems are discussed.

• The KIPS Transactions:PartD
• /
• v.15D no.5
• /
• pp.699-704
• /
• 2008

By the dependence on Web from popularization of internet and increasing number of users, web services capability and security problem of communication is becoming a great issue. Existing web services technology decrease the capability of web application server by limiting the number of synchronous client, decreasing the processing load and increasing average response time. The encryption process to secure communication and the early expense of handshake decrease transmission speed and server capability by increasing the calculation time for connecting. Accordingly, this paper executes an encryption procedure by elliptical encryption algorithm to satisfy secure demands, improve the overload of server for web services and get reliability and security of web server architecture and proposes an improved mobile web sever which provides better ability and the techniques for deferred processing.

• The Journal of the Acoustical Society of Korea
• /
• v.17 no.4E
• /
• pp.28-34
• /
• 1998

In most switching system, the processing unit is designed to work efficiently even at relatively high loads, but when the offered traffic exceeds a particular level, the rate of completed calls can fall drastically. A single call handled by the switching system consists of a sequence of events or messages that has to be processed by the control unit. The control unit is not only incapable of handling all of the offered calls, but also its call handling capability can drop as the offered load increases. The real time available for call processing is a critical resource that requires careful management. Therefore, the overloading of this resource must be detected by a subscriber in the from of a dial tone delay or an uncompleted call which is either blocked or mishandled. The subscriber may respond by either dialing prematurely or by re-attempting a call. This action can further escalate the processors load, which is spent for uncompleted calls. Unless a proper control is used, the switching system can finally break down. In this paper, we paper, we propose a fuzzy overload detection and control method for switching systems, which can by generating fuzzy rules via fuzzy aggregation networks. Simulation results involving a switching system is given.

• Convergence Security Journal
• /
• v.16 no.7
• /
• pp.41-49
• /
• 2016

The need for protecting computerized medical information has been growing as information and communication technology has rapidly been developed. Government is also promoting institutional improvement measures for the information protection of medical institutions. With more emphasis upon the efforts to enhance the information protection capability of the medical institution, however, it could increase stress to the hospital workers and cause a reduction in the quality of essential medical services of medical institutions. Therefore, it is necessary to research the stress from hospital workers to strengthen the protection of information that medical institutions to manage and its antecedents. Based on the results of relevant researches, this study selected several factors that affect the security stress, including work overload, invasion of privacy and work uncertainty. The sample for this study was 123 hospital workers who were surveyed by questionnaire. The factor analysis and multiple regression method were employed for the analysis of this study. The results of this study showed that work overload, invasion of privacy and some of work uncertainty were the main factors positively influencing the security stress.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.12 no.4
• /
• pp.71-79
• /
• 2016

This study proposes a performance model of a shared bus multi-processor system and analyzes the effect of input/output types on system performance and overload of shared resources. This system performance model reflects the memory reference time in relation to the effect of input/output types on shared resources and the input/output processing time in relation to the input/output processor, disk buffer, and device standby places. In addition, it demonstrates the contribution of input/output types to system performance for comprehensive analysis of system performance. As the concept of workload in the probability theory and the presented model are utilized, the result of operating and analyzing the model in various conditions of processor capability, cache miss ratio, page fault ratio, disk buffer hit ratio (input/output processor and controller), memory access time, and input/output block size. A simulation is conducted to verify the analysis result.