• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.6
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• pp.28-38
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• 2001

In this paper, we propose and analyze a more efficient and flexible dynamic data traffic system for a circuit switched satellite network. Our proposed system is more efficient than existing circuit switched satellite networks and allows for dynamic capacity in each connection without rebuilding or resetting the connection software or algorithms. We also discuss an algorithm for bandwidth allocation that provides deterministic quality of service guarantees. The traffic sources are regulated using standard dual leaky buckets; the system performance is analytically evaluated; and the algorithm is verified through simulation. Our analysis scheme and results should prove useful for the design and implementation of protocols in future circuit-switched satellite networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.5
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• pp.452-459
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• 1992

In this paper, we have estimated voice traffics using Kalman-filtering for upcoming years and evaluated performance of a grid topology circuit switched network using above outcomes. Since measurement errors and modeling errors are considered in Kalman-filtering, the system is estimated more accurately than by using any other estimation methods. A grid topology circuit switched network has alternative routing paths, therefore it is more reliable than any other networks. In this paper, we have calculated the call blocking probabilities, which is the key measuremens of performance evaluation in circuit switched networks. by using estimated voice traffics for upcoming years.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1166-1168
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• 2003

In most power electronic applications, the AC power input provided by the electronic utility needs to first converted to a DC voltage. Such conversion is accomplished by a diode rectifier due to its circuit simplicity and low cost. However, since diode rectifiers have some intrinsic problems such as low power factor and high harmonic distortion, a wide use of such rectifiers may cause noises, malfunction and heat damage in both electrical power systems and electrical machinery systems. This paper proposes soft switched three-phase single switch boost-type converter. The proposed circuit can perform Zero Voltage Switched(ZVS) without using any current and voltage sensors. For this circuit, both simulation and experiments have been performed. The results not only confirmed the ZVS but also indicated that, compared to the conventional hard switched converter, the prosed circuit can improve the efficiency as much as 1.7 to 4.7[%] while keeping the same high power factor and small harmonic distortion in their AC input.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.58-60
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• 2009

This paper deals with force characteristic analysis of linear switched reluctance motor using dynamic simulation. First, we calculated flux density of linear switched reluctance motor according to position. Second, analyzed normal force from flux density of linear switched reluctance motor according to position. Also, analysis result compares with data that is derived through a finite element analysis, and proved validity. However, linear switched reluctance motor has non linear characteristic, hence, analysis of propulsion force do not easy using analytical method. Therefore, we presented dynamic characteristic analysis model which is consisted at motor and sensor signal part, etc., and substitute circuit constant that get using magnetic equivalent circuit method, we confirmed propulsion force.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.185-188
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• 1998

The recent flurry of activities and interest in Switched Reluctance Motor(SRM) has focused attention on various issues associated with implementing the SRM in the mass commertial Market. One such issue is the noise generated by radial force. In this paper, we proposed the circuit to reduce the noise of SRM using LC Resonant characteristic. The usefulness of proposed circuit is verified by experimental result.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.3
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• pp.360-371
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• 1993

Flood search algorithm is known to be an effective routing mechanism for tactical application, since it provides high degree of survivability and robustness. But it is known that it has significant drawbacks with respect to the network efficiency [1]. We consider a tactical circuit-switched grid network with a maximum of four links and two priority classes of voice traffic, Using the minimum first-derivative length (MFDL) path, we improve the blocking probability performance of the circuit-switched network without increasing the call set-up time and processor loading of the algorithm.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.12
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• pp.1-8
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• 1994

In this paper, we hve compare the performance of DAR(Dynamic Adaptive Routing) with that of FSR(Flooding Search Routing) to select an adequate routing protocol in circuit-switched networs. As a performance factor, we have considered call setup time, which is the key factor of performance evaluation in circuit switched networks. We have evaluated the performance of two methods in grid topology circuit-switched networks using a commn channel signaling scheme, as application examples. As results, FSR method shows better performance than DAR method under light traffic load, when the number of links by which call has passed increases, but DAR method represents better performance than FSR method under heavy traffic load or large networks because of redundant packets.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.7
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• pp.952-965
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• 1995

In the hypercube multiprocessor system. repeated allocations and deallocations of subcubes generate a fragmented hypercube from which. even if sufficient free processors are available, a subcube that is large enough to accomodate a new task cannot be formed. To eliminate the fragmentation, we need a processor relocation to move a task-occupied subcube to a free subcube, and gather dispersed small subcubes. In this paper, we propose a routing algorithm for task migration in circuit- switched hypercube to relocate processors. In the circuit-switched hypercube, we have to find a set of dedicated link-disjoint routing paths for each node to move a task from a busy subcube to a free subcube in fragmentation. The proposed algorithm is based on the PGC(packed Gray code) which detects all kinds of subcubes.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.10
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• pp.1839-1844
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• 2010

A power management controller circuit with switched capacitor mode down regulator and battery charger block for semi-active RFID tags was proposed and fabricated. The main purposes of the proposed switched capacitor mode down regulator and battery charger block are to reduce standby current and to provide a self-controlled thin film battery charger by detecting the received RF power, respectively. Fabricated chip area is $360,000{\mu}m^2$ and measured standby current was about $1.3{\mu}A$. To further reduction of standby current, a wake-up circuit has to be included in the power management controller.

• Journal of Power Electronics
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• v.15 no.6
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• pp.1468-1479
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• 2015

Renewable energy resources such as wind and photovoltaic power generation systems demand a high step-up DC-DC converters to convert the low voltage to commercial grid voltage. However, the high step-up converter using a transformer has limitations of high voltage stresses of switches and diodes when the transformer winding ratio increases. Accordingly, conventional studies have been applied to series-connect multioutput converters such as forward-flyback and switched-capacitor flyback to reduce the transformer winding ratio. This paper proposes new single-ended converter topologies of an isolation type and a non-isolation type to improve power efficiency, cost-effectiveness, and output ripple. The first proposal is an isolation-type charge-pump switched-capacitor flyback converter that includes an extreme-ratio isolation switched-capacitor cell with a chargepump circuit. It reduces the transformer winding number and the output ripple, and further improves power efficiency without any cost increase. The next proposal is a non-isolation charge-pump switched-capacitor-flyback tapped-inductor boost converter, which adds a charge-pump-connected flyback circuit to the conventional switched-capacitor boost converter to improve the power efficiency and to reduce the efficiency degradation from the input variation. In this paper, the operation principle of the proposed scheme is presented with the experimental results of the 100 W DC-DC converter for verification.