• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.47-50
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• 2000

In the Multirate DS/CDMA system based on VSL(Variable Spreading Length), the problem of the multiple access interference and effect similar to near-far effects in current system is generated. This problem can degrade performance of the system badly. Therefore, In this paper we proposed Hybrid Interference Cancellation to overcome this problems, Simulation result presents that the proposed Hybrid Interference Cancellation has the better performance than the conventional decorrelator, Parallel Interference Cancellation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.97.1-100
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• 1998

We studied on the ultra thin L- $\alpha$ -DLPC by LB method. The $\pi$ -A isotherm of the L- e -DLPC was measured at the air-water interface varying with the compressing speed and amounts of solutions for spreading. The molecular arrangement of deposited films were evaluated by measuring the absorption with the UV spectrometer. And we made structures of metal(Au)/L- $\alpha$ -DLPC/Metal(Au) and examined electron through L- $\alpha$ -DLPC LB films by means of current-voltage(I- V) measurement

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.3
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• pp.267-273
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• 1992

An advanced on-resistance model of VDMOS devices in the low voltage regimes is proposed and verified by 2-D device simulations. The model considers the lateral gaussian doping profiles in the channel region and exact current spreading angles in the epitaxial layer for both linear and cellular geometries by employing the conformal mapping, It is found out that the on-resistance of low voltage VDMOS may be overestimated considerably if it is analyzed by the conventional method. The 2-D device simulation results show that the proposed model is valid for the VDMOS devices in the low voltage regimes.

• 한국디지털정책학회:학술대회논문집
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• 2007.06a
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• pp.23-32
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• 2007

Most recently, the development and publication of the ordinance and the manual of policy qualify management is spreading the recognition of quality Control in the public sector. The purpose of this study is to introduce of the system quality Control for local government's policy. So we suggested lessons drew from case study(Daegu metropolitan city, Gumi city) on current introduction. To introduce the system quality Control for local government, we have to gain the sympathy of introduction, second prepare of inducement, last manage PQM flexibility.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.1
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• pp.112-120
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• 2006

It is possible to divide the historical changes of slope revegetation in Japan into five periods as follows; 1) The early period after creation(1927-1948), 2) The spreading period of modern revegetation work with manpower(1947-1958), 3) The spreading period of rapid revegetation technique using exotic grasses with machineries(1959-1985${\dots}$), 4) The spreading period of rapid reforestation technique by fast growing species mainly using leguminous shrub species(1986-1995${\dots}$), 5) The developing period of nature restoration technique using endemic arborous species(1996-). Recently main purpose of slope revegetation has been developing from the erosion protection to the nature restoration in the current of the 5th period. It is said that the role of the Japanese Society of Revegetation Technology(JSRT) is critical to the history of slope revegetation in Japan. 'The tentative guidelines of slope nature restoration' was announced by JSRT in 2004. In the guidelines, it was proposed that the planning techniques of using suitable seeds/plants based on the preservation level at the each construction sites. Moreover, the use of soil seed bank is the new and important study theme in the field of nature restoration. Consequently, at present the importance of advanced monitoring methods for vegetation maintenance and plant sociologic survey to evaluate the plant succession is increasing. Finally, some critical concepts are necessary to develop the field of restoration in Korea as follows; 1) monitoring of constructed sites, 2) ensuring of biodiversity, 3) recognition of slow revegetation and mosaic arrangement in revegetation, 4) reuse and recycle on the construction sites, and 5) promotion of specialist.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.2
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• pp.83-89
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• 2005

The historical changes of seeding work in Japan, the typical slope revegetation method, is possible to divide into five periods as follows; 1) The early period after creation(1927-1948) 2) The spreading period of modern revegetation work with manpower(1947-1958) 3) The spreading period of rapid revegetation technique using exotic grasses with machineries(1959-1985${\dots}$) 4) The spreading period of rapid reforestation technique by fast growing species mainly using leguminous shrub species(1986-1995${\dots}$) 5)The developing period of nature restoration technique using endemic arborous species(1996-) The evaluation basis of vegetated condition after slope seeding has been described to a official guide book, "The Standards of Slope Stabilizing Works" It was mainly revised three times after first edition in 1972, and also the point of evaluation basis changed from the vegetation coverage to the density of woody plant through the 3rd period and the 4th period Recently main purpose of slope seeding has been developing from the erosion protection to the nature restoration in the current of the 5th period, and "The tentative guidelines of slope nature restoration" was announced by The Slope Revegetation Section of Japanese Society of Revegetation Technology in 2004. It was proposed the planning techniques of using suitable seeds/plants based on the preservation level at the real each construction sites Consequently, at present the importance of advanced monitoring methods for vegetation maintenance and plant sociologic survey to evaluate the plant succession is increasing.

• Geomechanics and Engineering
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• v.3 no.1
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• pp.1-16
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• 2011

Piles passing through sloping liquefiable deposits are prone to lateral loading if these deposits liquefy and flow during earthquakes. These lateral loads caused by the relative soil-pile movement will induce bending in the piles and may result in failure of the piles or excessive pile-head displacement. Whilst the weak nature of the flowing liquefied soil would suggest that only small loads would be exerted on the piles, it is known from case histories that piles do fail owing to the influence of laterally spreading soils. It will be shown, based on dynamic centrifuge test data, that dilatant behaviour of soil close to the pile is the major cause of these considerable transient lateral loads which are transferred to the pile. This paper reports the results of geotechnical centrifuge tests in which models of gently sloping liquefiable sand with pile foundations passing through them were subjected to earthquake excitation. The soil close to the pile was instrumented with pore-pressure transducers and contact stress cells in order to monitor the interaction between soil and pile and to track the soil stress state both upslope and downslope of the pile. The presence of instrumentation measuring pore-pressure and lateral stress close to the pile in the research described in this paper gives the opportunity to better study the soil stress state close to the pile and to compare the loads measured as being applied to the piles by the laterally spreading soils with those suggested by the JRA design code. This test data shows that lateral stresses much greater than one might expect from calculations based on the residual strength of liquefied soil may be applied to piles in flowing liquefied slopes owing to the dilative behaviour of the liquefied soil. It is shown at least for the particular geometry studied that the current JRA design code can be un-conservative by a factor of three for these dilation-affected transient lateral loads.

• Journal of KIISE:Information Networking
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• v.29 no.2
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• pp.141-155
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• 2002

A medium access control protocol is proposed for integrated voice and data services in the packet CDMA network with a small coverage. Uplink channels are composed of time slots and multiple spreading codes for each slot. This protocol gives higher access priority to the delay-sensitive voice traffic than to the data traffic. During a talkspurt, voice terminals reserve a spreading code to transmit multiple voice packets. On the other hand, whenever generating a data packet, data terminals transmit a packet based on the status information of spreading codes in the current slot, which is received from base station. In this protocol, voice packet does not come into collision with data packet. Therefore, this protocol can increase the maximum number of voice terminals.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.287.1-287.1
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• 2016

Three-dimensional (3-D) semiconductor nanoarchitectures, including nano- and micro- rods, pyramids, and disks, are emerging as one of the most promising elements for future optoelectronic devices. Since these 3-D semiconductor nanoarchitectures have many interesting unconventional properties, including the use of large light-emitting surface area and semipolar/nonpolar nano- or micro-facets, numerous studies reported on novel device applications of these 3-D nanoarchitectures. In particular, 3-D nanoarchitecture devices can have noticeably different current spreading characteristics compared with conventional thin film devices, due to their elaborate 3-D geometry. Utilizing this feature in a highly controlled manner, color-tunable light-emitting diodes (LEDs) were demonstrated by controlling the spatial distribution of current density over the multifaceted GaN LEDs. Meanwhile, for the fabrication of high brightness, single color emitting LEDs or laser diodes, uniform and high density of electrical current must be injected into the entire active layers of the nanoarchitecture devices. Here, we report on a new device structure to inject uniform and high density of electrical current through the 3-D semiconductor nanoarchitecture LEDs using metal core inside microtube LEDs. In this work, we report the fabrications and characteristics of metal-cored coaxial $GaN/In_xGa_{1-x}N$ microtube LEDs. For the fabrication of metal-cored microtube LEDs, $GaN/In_xGa_{1-x}N/ZnO$ coaxial microtube LED arrays grown on an n-GaN/c-Al2O3 substrate were lifted-off from the substrate by wet chemical etching of sacrificial ZnO microtubes and $SiO_2$ layer. The chemically lifted-off layer of LEDs were then stamped upside down on another supporting substrates. Subsequently, Ti/Au and indium tin oxide were deposited on the inner shells of microtubes, forming n-type electrodes of the metal-cored LEDs. The device characteristics were investigated measuring electroluminescence and current-voltage characteristic curves and analyzed by computational modeling of current spreading characteristics.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.2
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• pp.111-115
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• 2022

Objectives: The purpose of this study is to verify whether droplet-induced propagation, the main route of infectious diseases such as COVID-19, can occur in semiconductor FAB (Fabrication), based on research results on general droplet propagation. Methods: Through data surveys droplet propagation was modeled through simulation and experimental case analysis according to general (without mask) and mask-wearing conditions, and the risk of droplet propagation was inferred by reflecting semiconductor FAB operation conditions (air current, air conditioning system, humidity, filter conditions). Results: Based on the results investigated to predict the possibility of spreading infectious diseases in semiconductor FAB, the total amount of droplet propagation (concentration), propagation distance, and virus life in FAB were inferred by reflecting the management parameter of semiconductor FAB. Conclusions: The total amount(concentration) of droplet propagation in the semiconductor fab is most affected by the presence or absence of wearing a mask and the line air dilution rate has some influence. when worn it spreads within 0.35~1m, and since the humidity is constant the virus can survive in the air for up to 3 hours. as a result the semiconductor fab is judged to be and effective space to block virus propagation due to the special environmental condition of a clean room.