• Journal of IKEEE
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• v.17 no.2
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• pp.176-181
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• 2013

This paper presents a CMOS impulse radio ultra-wideband (IR-UWB) receiver implemented using IBM 0.13um CMOS technology for inner/inter-chip wireless interconnection. The IR-UWB receiver is based on the non-coherent architecture which removes the complexity of RF architecture (such as DLL or PLL) and reduces power consumption. The receiver consists of three blocks: a low noise amplifier (LNA) with active balun, a correlator, and a comparator. Simulation results show the die area of the IR-UWB receiver of 0.2mm2, a power gain (S21) of 12.5dB, a noise figure (NF) of 3.05dB, an input return loss (S11) of less than -16.5dB, a conversion gain of 18dB, a NFDSB of 22. The receiver exhibits a third order intercept point (IIP3) of -1.3dBm and consumes 22.9mW of power on the 1.4V power supply.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.549-552
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• 2002

The objective of this study is to clarify the detailed performances of the impulse type radial turbine and to present an optimum configuration of the turbine. The impulse type radial turbine has been manufactured and investigated experimentally under steady and sinusoidally oscillating flow conditions by model testing. Then, the starting characteristics under sinusoidally flow conditions have been evaluated by a numerical simulation using a quasi-steady analysis. As a result, the running and starting characteristics of the impulse type radial turbine for wave energy conversion have been clarified. Furthermore, the recommended configuration is presented, especially for setting angles of inner and outer guide vanes.

• Corrosion Science and Technology
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• v.3 no.5
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• pp.209-215
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• 2004

Flexible hydraulic hose assembly that consists of hose and joints is used widely on various construction heavy equipments, agricultural machines, motor vehicles, and industrial heavy machines that require flexibility on hydraulic pipelines. It is classified by the maximum usage pressure which is determined by the winding layers of coiling steel wire and the inner diameter of the hoses. In this paper, we designed and performed an accelerated life test for assessing the reliability of a flexible hydraulic hose assembly. In the proposed accelerated life test, typical impulse pressure testing method is applied with the half omega flexing operation to simulate the practical flexing motion of the hose assembly.

• Journal of Korea Port Economic Association
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• v.30 no.4
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• pp.255-273
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• 2014

The purpose of this paper is to examine the causal relationship among the trading volume of Pyeongtaek port, Incheon Inner Harbor, Incheon North Harbor. Methodologically, Granger causality, impulse response function, and variance decomposition based on VAR are used. The results indicate that Pyeongtaek port trading volume positive shock has positive effects on Incheon North Harbor. In addition, Incheon Inner Harbor trading volumes positive shock has negative effects on Pyeongtaek port. The results also suggest that the volume of Pyeongtaek port Granger-causes the volume of Incheon North Harbor, but not vice versa. The volume of Incheon Inner Harbor Granger-causes the volume of Pyeongtaek port. Based on these results, we suggest that port authorities have to focus on policies that would promote copetition between port of Pyeongtaek and Incheon in the world harbor industry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.45-45
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• 2010

This paper discusses the simulation and LI(light impulse) test of the shieldless vacuum interrupter concept. The shields of vacuum interrupter play an important role in absorbing the metal vapor. But shield distort the electric field distribution of inner vacuum interrupter. Therefore, the insulation efficiency will improve. if shield of vacuum interrupter inside does not exist. As a result, FEM simulation show that improve distribution of electrical field and equi-potential line. But LI test result dissimilar to FEM simulation result. Shieldless vacuum interrupter model lower BIL(breakdown impulse light) than vacuum interrupter have installed shield. Because conditioning process occurred metal vapor. This paper compared that FEM analysis and LI test of installed shield model and shieldless model.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.2
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• pp.249-255
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• 2013

A large-sized refrigerator has a complicated inner structure such as a shelf and a rack for product loading. Therefore, when the refrigerator door is opened and closed, the temperature inside the refrigerator varies and vibrations occur due to the physical force applied for opening and closing the door. Owing to these factors, an abnormal sound is generated by the relative distortion between the inner structures. In this study, we aimed to clarify the mechanism that generates this abnormal noise inside the refrigerator using experimental approaches, and we also investigated ways by which to reduce this noise. Toward this end, we developed an experimental setup for measuring the noise, temperature, inner pressure, as well as amount of vibration, and we analyzed the main factors causing the noise based on the experimental results. Furthermore, we suggested a way by which to reduce the noise; this method can be applied in the design stage itself.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.10
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• pp.479-484
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• 2002

Recently it is reported that many a malfunction of ELB which is represented by non-operated type ELB for an impulse wave, is caused by lightning impulse and transient ground potential rise due to nearby lightning strokes. In order to examine the cause of malfunction, 5 samples were investigated experimentally in this study. As each ELB has a different leakage current detecting circuit and wiring method, various characteristics were measured. As a result, all of them brought about malfunctions under the lightning impulse voltage less than 7 kV and the surge current less than 3 kA. Also the different aspects were measured with a polarity of injected surge and a position of MOV to protect the inner circuit of ELB. The Position and effects of protecting devices were suggested as a remedy.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1978.06a
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• pp.9.1-10
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• 1978

Recently the authors have observed various wave-forms by insertion of induction coil into the scala tympani as well as attached outer device in the outside of the body in damaged hair cells of the cats. In the cochlear nerve. action potential indicated different polarities induced by examination of the bundle of the cochlear nerve fibers. Impulse wave-form as a result of excitation of cohlear nerve fibers showed bipolar wave-form such as negative 1 and positive 1. Therefore action potential showed also bipolar wave-form as above mentioned. We can obtained suitable response with above mentioned outer and inner device as an exact oscillogram.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.6
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• pp.83-90
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• 1995

This paper analyzed the electrical field strength of porcelain suspension insulator used various testing methods in order to present the causes and countermeasure for the puncture failure by the inner minute defect. A power frequency puncture test and a step-front-of-wave flashover voltage test were conducted. The failed specimen of these samples was analyzed material characteric observed the cross-sectional picture by the scanning electron microscope, and tested the autoclave expansion for the portland cement using the metal bond agent. The porcelain made a progress the failure by the thermal expansion coefficient of the different material. The inner detecting technique on behalf of the puncture failure protection is presented such as the steep-front-of-wave flashover voltage test.

• Journal of Communications and Networks
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• v.1 no.3
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• pp.166-181
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• 1999

The object of this paper is to investigate the influence of antenna pattern on indoor radio channel characteristics. Different from previous works where this analysis was carried out at a fixed frequency using different antennas, in the present paper (where measurements were taken in a wide frequency range) the variation of the radiation pattern was caused by two factors: the change of the radiation pattern when the same antenna was used at different frequenicies and the use of different type of antennas. To carry out this analysis, frequency domain measurements of the indoor radio channel at 1 GHz, 5.5 GHz, 10 GHz and 18 GHz were collected. Measurements were taken using a network analyzer. Serveral re-alizations of the channel transfer function were obtained varying, for each measurement, the positon of the transmitter and keep-ing the receiver fixed. Estimate of the channel impulse response was obtained from the Inverse Fourier Transform (IFT) of the fre-quency response. The measurements were performed in an office enviroment with mostly metallic walls and inner separations. The obtained data were elaborated to obtain the power versus distance relationship, the Cummulative Distribution Functions(CDFs) of rms Delay Spread(DS) and of the 3 dB frequency correlation band-width. Finally, the 3 dB width of the frequency correlation func-tion has been empirically related to the inverse of the rms DS of the impulse response.