• Journal of Korean Institute of Industrial Engineers
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• v.19 no.4
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• pp.87-96
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• 1993

Spectrum analysis of surface electromyogram (FMG) signals is an effective approach to the study of localized muscular fatigue during isometric contraction. Many investigators have con firmed the frequency of the EMG signals being lowered during sustained contaction. In this study, the cyclic loading tasks were performed, and a comparison was made for the median power frequency shift pattern of the EMG signals with the sustained contraction of the same load. The median power frequency shift of the EMG signals for the cyclic loading task was found to be a part of that for the sustained contraction. Based on this result, a new muscle fatigue index was computed by normalizing the duration of the sustained contraction. A fatigue index was obtained as a function of exertion level and the work/rest schedule. With the proposed fatigue index, it is possible to evaluate or predict the degree of muscular fatigue for a physically demanding task.

• Geomechanics and Engineering
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• v.13 no.5
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• pp.809-823
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• 2017

This paper describes lab test results of artificial rock-like material samples having a plane joint. Cyclic shear tests were performed under different normal loads and different shear displacement amplitudes. For this purpose, multi-stage normal loading tests (30 kN, 60 kN, 90 kN, 180 kN, 360 kN and 480 kN) with cyclic excitation at frequency of 1.0 Hz and different shear displacement amplitudes (0.5 mm, 1.0 mm, 2.0 mm, 4.0 mm, 5.0 mm, and 8.0 mm) were conducted using the big shear box device GS-1000. Experimental results show, that shear forces increase with the increase of normal forces and quasi-static friction coefficient is larger than dynamic one. With the increase of normal loads, approaching the peak value of shear forces needs larger shear displacements. During each cycle the normal displacements increase and decrease (rotational behavior in every cycle). Peak angle of inclination increases with the increase of normal load. A phase shift between maximum shear displacement and maximum shear force is observed. The corresponding time shift decreases with increasing normal load and increases with increasing shear displacement amplitudes.

• 한국ITS학회:학술대회논문집
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• 2008.11a
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• pp.543-547
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• 2008

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.12
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• pp.1351-1358
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• 2012

In this paper, an analytical technique is proposed for the design of interleaved thinned planar array with well-behaved and predictable sidelobes. The interleaved arrays are composed of thinned planar subarrays based on cyclic difference sets(DSs). Becauce sidelobes of thinned planar subarrays based on DS are predictable by DS parameters, the subarrays exhibit very similar sidelobe levels by utilizing DS and complementary DS with similar autocorrelations each other. The combinatorial method also allows the design of interleaved placements with simultaneously optimum peak sidelobe levels(PSLs) of subarrays using cyclic shift-a property of DSs. The optimized PSLs of the interleaved array are -12.47 dB and -10.34 dB.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.853-855
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• 2005

현재 표준화가 진행중인 SVC(Scalable Video Codec)에는 기존의 FGS방법이 아닌 Cyclic-FGS를 사용하여 영상을 강화하고 있다. 이 Cyclic-FGS 블록간에 Stocking Effect를 줄일 수 있고 넓은 영역을 강화할 수 있다는 장점이 있다. 하지만 널은 영역을 강화하기 때문에 기존의 FGS와 달리 ROI를 강화하는데는 적합하지 않다. 따라서 본 논문에서는 Cyclic-FGS에 적합한 새로운 Ordering 방법을 제안한다. 이 방법을 사용하면 기존의 FGS에서 사용한 Bit-shift방법을 사용하지 않고도 비슷한 효과를 낼 수 있으며, 우리가 원하는 ROI를 강화시킬 수 있다. ROI를 중점적으로 강화를 하다 보면 전체 영상에 대한 화질은 떨어질 수 있다. 그러나 두 가지 모드를 두어서 중점강화 또는 전체영상과 비교해 화질열화가 거의 없는 강화를 할 수 있게 하였다.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.4
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• pp.161-164
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• 2005

Viologen has been extensively investigated in the paper because their well-behaved electrochemistry has led to their use in a variety of theses, including the electron acceptor for the electric charge delivery mediation of the devices. It was formed monolayer in QCM by self-assembly method. We could know the adsorbed mass of viologen molecules from the frequency shift. We calculated that the adsorbed mass was about 196 [$ng/cm^2$]. We studied the electron transfer property of viologen by the cyclic voltammetry among the electrochemical process so we changed an anion like 0.1 M $NaClO_4$ and $Na_3PO_4$ electrolyte solution and investigated the interrelationship between scan rate and peak current when scan rates were increased twice.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1C
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• pp.1-8
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• 2005

In this paper, we present a novel LDPC code construction called as semi-algebra low density parity check(LDPC) codes which is one kind of deterministic LDPC code based on dual-diagonal sub-matrix. The constructing method results in a class of high rate LDPC codes. Codes in this class have a large girth and good minimum distances. Furthermore, they can be implemented by simple parallel array architecture using cyclic shift register and perform well with the iterative decoding.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.395-396
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• 2005

We fabricated self-assembled monolayers(SAMs) onto quartz crystal microbalance(QCM) using viologen, which has been widely used as electron acceptor and electron transfer mediator. We determined the time dependence to resonant frequency shift during self-assembly process and observed the morphology of self-assembled mono layers by STM and investigated the electrochemical behavior of SAMs by cyclic voltammetry. Electrochemical deposition of viologen was investigated using electrochemical quartz crystal microbalance(EQCM). The redox reactions of viologen were highly reversible and the EQCM has been employed to monitor the electrochemically induced adsorption of SAMs during the redox reactions.

• Structural Engineering and Mechanics
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• v.21 no.1
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• pp.1-18
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• 2005

Foschi's connector model is used as a basic component in the development of nonlinear analysis programs for timber structures. This paper presents the extension of the model to include the effect of shaft frictional forces. The wood medium is modeled using the Foschi embedment model, while shaft friction is modeled using an elastic Coulomb-type friction model. The initial confining pressure for the case of driven fasteners is accounted for by a lateral shift of the load-embedment curve. The model is used to compute the cyclic response of both driven and inserted fasteners. The results obtained from the cases studied indicate that initial confining pressure and friction do not have a significant effect on the computed hysteretic response, however, they significantly affect the computed amount of fastener withdrawal. This model is particularly well-suited for modeling the hysteretic response of shear walls with moderate fastener withdrawal under lateral cyclic or earthquake loading.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9A
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• pp.835-843
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• 2010

Energy spreading transform (EST) based equalization is a very effective technique to remove inter symbol interference (ISI) in frequency selective channel. EST based system uses cyclic prefix (CP) similar to orthogonal frequency division multiplexing (OFDM) system. Since CP is a redundancy, it degrades the data transmission rate. RISIC is an algorithm that removes an inter block interference (IBI) caused by insufficient CP length and reconstructs CP. In this paper, we propose a system that combines the existing EST system with quadrature phase shift keying (QPSK) modulation and RISIC algorithm to enhance the efficiency of the transmission. Also we extend the proposed system to 16 quadrature amplitude modulation (QAM) modulation. The proposed system is shown to performance close to matched filter bound (MFB) even with insufficient CP.