• Structural Engineering and Mechanics
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• v.61 no.3
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• pp.371-379
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• 2017

Modelling of a crack propagating through a finite element mesh under mixed mode conditions is of prime importance in fracture mechanics. In this paper, two crack growth criteria and the respective crack paths prediction in functionally graded materials (FGM) are compared. The maximum tangential stress criterion (${\sigma}_{\theta}-criterion$) and the minimum strain energy density criterion (S-criterion) are investigated using advanced finite element technique. Using Ansys Parametric Design Language (APDL), the variation continues in the material properties are incorporated into the model by specifying the material parameters at the centroid of each finite element. In this paper, the displacement extrapolation technique (DET) proposed for homogeneous materials is modified and investigated, to obtain the stress intensity factors (SIFs) at crack-tip in FGMs. Several examples are modeled to evaluate the accuracy and effectiveness of the combined procedure. The effect of the defects on the crack propagation in FGMs was highlighted.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.5
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• pp.661-666
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• 2015

This paper proposes a method for solving running cost problem by minimizing switching reactive power compensation devices. An objective function was modeled by calculating the weighting value of cost, and a solution was derived using ILP. This paper suggests optimal coordinative control method between FACTS, Shunt Reactors, Capacitors and OLTC. Therefore, it is valuable for decision maker in determining order and capacity of devices which gaining a voltage stabilization. As a result, the objectives of voltage stabilization and cost minimization were achieved simultaneously. This realizes the economic efficiency of the system. We start by showing how to solve systems of linear equations using the language of pivots and tableaus. The effectiveness of this technique is demonstrated in modified PSS/E MIGUM 45 bus system. The simulation results show the effectiveness of this algorithm by comparing the outcome withseveral established methods.

• Journal of KIISE:Software and Applications
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• v.31 no.3
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• pp.317-331
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• 2004

Recently software agent has been studied as a new abstraction unit of software engineering. The agent with autonomous, adaptability and cooperation attribute is accepted as a new abstraction unit especially in distributed systems, open systems, and complex systems. However, the progress of agent research has been slow and the realization of agent programming language seems to be far distant. Because the properties of agent are diverse, the opinions of researchers can not converge to one. In this situation, software agent framework is accepted more realistic alternative solution. However the knowledge for its development doesn't have been shared among developers. So they often have to make same errors. We will help sharing of knowledge and experience by using pattern language which has been used in object technology for long times. This paper proposes a reactive agent framework pattern language and validates it based on ATAM［l］ The increase of such indirect experience can reduce the waste of resource by preventing the same try and error. So agent framework developers are able to concentrate on more essential issues. Finally quality of software agent framework will be increased.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.373-375
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• 2008

TTCN-3(Testing & Test Control Notation Version 3) defined in EISI(2001) are the standardized test specification and test implementation language of applicable for all kinds of black-box testing for reactive and distributed system, telecom systems, Mobile system, Internet, CORBA based system, java, XML, etc. This paper using the TTCN-3 on an Electric Power IT Protocol DLMS(Device Language Message Specification) standards for the implementation of the device equipment test the suitability of the protocol.

• Journal of the Korea Society of Computer and Information
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• v.11 no.6 s.44
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• pp.49-57
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• 2006

While developing a complex reactive software system. it is very important to analyze the user requirement and reflect it to the developed system. Therefore understanding the need of users precisely and promptly is the key to the successful software system development. Among several requirement specification languages, message sequence charts (MSCs), also known as sequence diagrams in UML are the most widely used scenario notation. Live Sequence Charts (LSCs) are a variant ot MSCs, characterized by its message abstraction facility and the modality of scenarios. In this paper, I define the formal semantics of LSC specification including the essential language constructs such as pre-charts, variables, assignment and conditions. The range of the formalized LSC language has been broadened, and the scope of the formalized semantics is much closer to the complete LSC specification.

• Journal of International Academy of Physical Therapy Research
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• v.1 no.2
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• pp.107-112
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• 2010

The majority of strokes are caused by ischemia and result in brain tissue damage, leading to problems of the central nervous system including hemiparesis, dysfunction of language and consciousness, and dysfunction of perception. The purpose of this study was to investigate the effects of Poly(ADP-ribose) polymerase(PARP) on necrosis in neuronal cells that have undergone needle electrode electrical stimulation(NEES) prior to induction of ischemia. Ischemia was induced in male SD rats(body weight 300g) by occlusion of the common carotid artery for 5 min, after which the blood was reperfused. After induction of brain ischemia, NEES was applied to Zusanli(ST 36), at 12, 24 and 48 hours. Protein expression was investigated using immuno-reactive cells, which react to PARP antibodies in cerebral nerve cells, and Western blotting. The results were as follows: In the cerebral cortex, the number of PARP reactive cells after 24 hours significantly decreased(p<.05) in the NEES group compared to the GI group. PARP expression after 24 hours significantly decreased(p<.05) in the NEES group compared to the GI group. As a result, NEES showed the greatest effect on necrosis-related PARP immuno-reactive cells 24 hours after ischemia, indicating necrosis inhibition, blocking of neural cell death, and protection of neural cells. Based on the results of this study, NEES can be an effective method of treating dysfunction and improving function of neuronal cells in brain damage caused by ischemia.

• Journal of Magnetics
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• v.21 no.2
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• pp.266-272
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• 2016

Transcranial magnetic stimulation devices has been used mainly for diagnostic purposes by measuring the functions of the nervous system rather than for treatment purposes, and has a problem of considerable energy fluctuations per repeated pulse. The majority of strokes are caused by ischemia and result in brain tissue damage, leading to problems of the central nervous system including hemiparesis, dysfunction of language and consciousness, and dysfunction of perception. Control is difficult and the size is large due to the difficulty of digitalizing the energy stored in a capacitor, and there are many heavy devices. In addition, there are many constraints when it is used for a range of purposes such as head and neck diagnosis, treatment and rehabilitation of nerve palsy, muscle strengthening, treatment of urinary incontinence etc. Output stabilization and minimization of the energy variation rate are required as the level of the transcranial magnetic stimulation device is dramatically improved and the demand for therapeutic purposes increases. This study developed a compact, low cost transcranial magnetic stimulation device with minimal energy variation of a high repeated pulse and output stabilization using a real time capacitor charge discharge voltage. Ischemia was induced in male SD rats by closing off the common carotid artery for 5 minutes, after which the blood was re-perfused. In the cerebrum, the number of PARP reactive cells after 24 hours significantly decreased (p < 0.05) in the TMS group compared to the GI group. As a result, TMS showed the greatest effect on necrosis-related PARP immuno-reactive cells 24 hours after ischemia, indicating necrosis inhibition, blocking of neural cell death, and protection of neural cells.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.6
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• pp.608-619
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• 2000

In this paper, we give a formal semantics for Statechart via a translation into Algebra of Communicating Shared Hesources(ACSR). Statechart is a very rich graphical specification language, which is suitable to specify complicated reactive systems. However, the incorporation of graph into specification and rich syntax makes Statechart semantics very complicated and ambiguous. Thus, it is very difficult to verify the correctness of Statechart specifications. Also, we propose the formal verification method for Statechart specifications by showing equivalence relation between two Statechart specifications. This makes it possible to combine the advantages of a graphical language with the rigor of process algebra.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1071-1074
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• 2002

In this paper, power quality analysis system is proposed where voltage or current waveforms are nonsinusoidal. The proposed system relies on the FFT algorithm to compute real and reactive power. The advantage of system is that harmonic analysis is carried out on a period of the input signal. The proposed system is based on FFT processor which is designed using VHDL(Very high-speed integrated circuit Hardware Description Language). In the design of FFT processor, radix- $2^2$ is adopted to reduce several complex multipliers for twiddle factor. Complex multiplier is implemented as only shifters and adders. Therefore, the system is able to have both high hardware efficiency and high performance.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.90-92
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• 2002

The SVC(Static Var Compensator) resulted from the FACTS technology can generate or absorb reactive power rapidly so as to increase the transient and voltage stability. In this paper, the SVC is applied to the power system in order to improve the total transfer capability from a viewpoint of static voltage stability and the effects of application of the SVC to the power system are analyzed. The IPLAN, which is a high level language used with PSS/E program, is employed for determining the total transfer capability.