• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2675-2677
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• 2005

공기조화설비의 계장 및 유지관리시에 공사와 조정 등을 간편화하고 로컬 레벨의 표준화 및 시스템간의 상호운용성을 높이기 위하여 공기조화설비 제어 계통도를 지하층(8포인트)과 기준층(15포인트)으로 나누어 설계하고 이것을 개방형 프로토콜인 $L_{ON}W_{ORKS]$를 이용하여 제어네트워크를 구축하였다. 네트워크의 자 디바이스는 뉴런 C로 프로그램 하였으며, 네트워크의 통신은 통신전용 배선공사를 간소화하기 위하여 전력선 통신을 사용하였다. 연구 결과 $L_{ON}W_{ORKS]$ 프로토콜로 각 디바이스들의 자율분산제어가 가능하게 되었고 통신선의 길이와 회선수를 감소시킬 수 있었다.

• Korean Journal of Materials Research
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• v.17 no.7
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• pp.371-375
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• 2007

In-situ observation of electromigration behavior of eutectic SnPb solder was performed as a function of line length at $100^{\circ}C$, $6{\times}10^4A/cm$ condition in a scanning electron microscope chamber. The incubation time for edge drift and the edge drift velocity increase as line length increases, which are discussed with the void nucleation stage of solder bump and the electromigration back flux force, respectively. Finally, the existence of electromigration product (jL) and its line length dependency are also discussed.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.12
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• pp.61-70
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• 2005

In this paper, we propose an efficient global placement algorithm which is an enhanced version of Hybrid Placer$^{[25]}$, a standard cell placement tool, which uses a middle-down approach. Combining techniques used in the well-known partitioner hMETIS and the RBLS(Relaxation Based Local Search) in Hybrid Placer improves the quality of global placements. Partitioning techniques of hMETIS is applied in a top-down manner and RBLS is used in each level of the top-down hierarchy to improve the global placement. The proposed new approach resolves the problem that Hybrid Placer seriously depends on initial placements and it speeds up without deteriorating the placement quality. Experimental results prove that solutions generated by the proposed method on the MCNC benchmarks are comparable to those by FengShui which is a well known placement tool. Compared to the results of the original Hybrid Placer, new method is 5 times faster on average and shows improvement on bigger circuits.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.332-337
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• 2006

We prepared 100 nm-thick CoNi composite silicide on a 70 nm-thick polysilicon substrate. Composite silicide laye.s were formed by rapid thermal annealing(RTA) at the temperatures of $700^{\circ}C,\;900^{\circ}C,\;1000^{\circ}C$ for 40 seconds. A Focused ion beam (FIB) was used to make nano-patterns with the operation range of 30 kV and $1{\sim}100$ pA. We investigated the change of thickness, line width, and the slope angle of the silicide patterns by FIB. More easily made with the FIB process than with the conventional polycide process. We successfully fabricated sub-100nm etched patterns with FIB condition of 30kv-30pA. Our result implies that we may integrate nano patterns with our newly proposed CoNi composite silicides.

• The Korean Journal of Zoology
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• v.4 no.1
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• pp.1-6
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• 1961

본 논문은 경기도광릉시험목에서 잣나무를 식해하는 한국미기록종 잣나무넓적잎벌(신칭)을 재료로 하여 1958-1961 년에 연구한 것을 기록한 것이다. (1) 본충은 막혈목 광요아목 편엽봉과의 Acantholyda nemoralis에 해당하는 것으로서, 이것의 학명으로는 R.B.Benson T의 설에 따라 Acantholyda posticalis posticalis MATSU.MURA를 채용하기로하였다. (2) 분포지로는 개지의 일본, 몽고, 시베리아 외에 한국을 추가한다. 구라파에서는 별개의 아종이 있다. 본종의 서식지로는 현재까지 경기도의 광fmd, 가평, 양주와 강원도의 충성군이 알려져있을 뿐이다. (3) 성충의 체색은 대체로 흑색이나, 두부와 훙부에 황색의 무늬가 많\ulcorner. 촉색은 황갈색 사상으로 유충은 웅충은 33절, 자충은 32절로 되었다. (4) 란은 QH트형으로 그 양단이 상외방으로 돌출, 산란직후의 색은 광택있는 담황갈색을 정하나 3일이 경과하면 담자황록색으로 변한다. 길이 약 3 mm , 폭 약 0.7mm이다. (5) 부화유충의 채색은 대적황색이나 , 머리와 흉곽은 흑색이다. 머리가 크고 몸통은 가늘다. 체장 약 3.5mm, 체폭 약 0.7mm. 성열유충의 체색은 담황갈색이나, 배선 및 기문상선은 선명한 적색이다. 3상의 흉곽과 한쌍의 미각이 있고, 망막은 없다. 두부는 키틴질화하였고, 갈색이며, 촉색은 7 절로되어 있고 대사가 발달하였다. 체장 약 27.4mm, 체폭 약 4.5mm , 전용은 적색의 배선 및 기문상선이 없고, 전신이 등황색이며, 촉색의 배측에 칠흑색의 커다란 복안을 가지고있는 점등이 성열유충과 다른 점이다. 암컷이 될 것은 크고 (체장 약 20-26mm), 수컷이 될 것은 작다(체장 약 3-17mm). (6) 용은 나용으로 용화직전의 것은 단지 복안과 단안만이 흑색을 정하고 , 타부분은 전부황색이지만 시간이 경과함에 따라 색이 변한다. 체장 약 17mm, 체폭 약 5mm.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.114-114
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• 2010

최근 고용량의 디커플링 캐패시터를 기판에 내장하여 고주파 발생의 원인인 배선길이와 실장 면적을 획기적으로 줄이는 임베디드 디커플링 캐패시터에 대한 연구가 활발히 진행되고 있다. 하지만 기존의 공정들은 높은 공정온도와 같은 공정상의 한계를 가지고 있어 상온 저 진공 분위기에서 세라믹 분말을 기판에 고속 분사시켜 기공과 균열이 거의 없는 치밀한 나노구조의 세라믹 제작이 가능한 후막코팅기술인 Aerosol Deposition Method (ADM)에 착목하였으며, 이 ADM을 박막공정으로 응용하여 $BaTiO_3$ 박막을 제작하고 고용량의 디커플링 캐패시터 제작을 실현하고자 한다. 하지만, Cu 기판 상에 성막 된 $0.5\;{\mu}m$이하의 $BaTiO_3$ 박막에서는 $BaTiO_3$ 분말 내에 존재하는 평균입자 보다 큰 입자와 응집분말로 인해 발생하는 pore, crater, not-fully-crushed particles와 같은 거시적인 결함들에서의 전류 통전과 울퉁불퉁한 $BaTiO_3$ 박막과 기판 사이의 계면에서의 전계의 집중에 의한 전류의 증가로 인하여 큰 누설전류 발생하는 문제에 봉착하였다. 이러한 문제를 해결하기 위하여 제시된 효과적인 방법으로 Stainless steel 기판과 같이 표면경도가 높은 기판을 사용하는 것이며, 이를 통해 $0.2\;{\mu}m$의 두께까지 유전 $BaTiO_3$ 박막을 성막 할 수 있었으며, 치밀한 표면 미세구조와 줄어든 $BaTiO_3$ 박막과 기판 사이의 계면의 거칠기를 확인하였다. 하지만, $BaTiO_3$ 박막 내에 발생하는 누설전류의 근본원인을 확인하기 위해서는 누설전류에 대한 미시적인 접근이 더욱 요구된다. 이에 본 연구에서는 누설전류 발생원인의 미시적 접근을 위해 두께에 따른 $BaTiO_3$ 박막의 누설전류 전도기구에 대한 조사하였으며, 이를 통해 $BaTiO_3$ 박막내 발생하는 누설전류의 원인은 $BaTiO_3$막 내에서 donor로서 역할을 하는 oxygen vacancy와 불균일한 전계의 집중으로 인한 전자의 tunneling 현상임을 확인할 수 있었다. 또한, Nano-indenter와 Conductive atomic force microscopic를 이용한 정밀 측정을 통해 표면경도의 중요성을 재확인하였으며 $BaTiO_3$ 박막의 두께가 $0.2\;{\mu}m$이하로 더욱 얇아지게 되면 입자간 결합 문제 또한 ADM을 박막화 하는데 있어 중요한 요소임을 확인하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.7
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• pp.21-28
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• 2017

Practical models for FPGA architectures which include performance- and/or density-enhancing components such as carry chains, wide function multiplexers, and memory/multiplier blocks are being applied to academic FPGA placement tools which used to rely on simple imaginary models. Previously the techniques such as pre-packing and multi-layer density analysis are proposed to remedy issues related to such practical models, and the wire length is effectively minimized during initial analytic placement. Since timing should be optimized rather than wire length, most previous work takes into account the timing constraints. However, instead of the initial analytic placement, the timing-driven techniques are mostly applied to subsequent steps such as placement legalization and iterative improvement. This paper incorporates the timing driven techniques, which check if the placement meets the timing constraints given in the standard SDC format, and minimize the detected violations, with the existing analytic placer which implements pre-packing and multi-layer density analysis. First of all, a static timing analyzer has been used to check the timing of the wire-length minimized placement results. In order to minimize the detected violations, a function to minimize the largest arrival time at end points is added to the objective function of the analytic placer. Since each clock has a different period, the function is proposed to be evaluated for each clock, and added to the objective function. Since this function can unnecessarily reduce the unviolated paths, a new function which calculates and minimizes the largest negative slack at end points is also proposed, and compared. Since the existing legalization which is non-timing driven is used before the timing analysis, any improvement on timing is entirely due to the functions added to the objective function. The experiments on twelve industrial examples show that the minimum arrival time function improves the worst negative slack by 15% on average whereas the minimum worst negative slack function improves the negative slacks by additional 6% on average.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.1
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• pp.8-18
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• 2000

We presented a BGA(Ball Grid Array) package for RF circuit modules and extracted its electrical parameters. As the frequency of RF system devices increases, the effect of its electrical parasitics in the wireless communication system requires new structure of RF circuit modules because of its needs to be considered of electrical performance for minimization and module mobility. RF circuit modules with BGA packages can provide some advantages such as minimization, shorter circuit routing, and noise improvement by reducing electrical noise affected to analog and digital mixed circuits, etc. We constructed a BGA package of ITS(Intelligent Transportation System) RF module and measured electrical parameters with a TDR(Time Domain Reflectometry) equipment and compared its electrical parasitic parameters with PCB RF circuits. With a BGA substrate of 3${\times}$3 input and output terminals, we have found that self capacitance of BGA solder ball is 68.6fF, and self inductance 146pH, whose values were reduced to 34% and 47% of the value of QFP package structure. S11 parameter measurement with a HP4396B Network Analyzer showed the resonance frequency of 1.55GHz and the loss of 0.26dB. Routing length of the substrate was reduced to 39.8mm. Thus, we may improve electrical performance when we use BGA package structures in the design of RF circuit modules.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.73-80
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• 2013

In this paper, an experimental circuit model for an accurate high-frequency characterization of transmission line is proposed. Inherent resonance effects during measurements make it difficult to determine characteristic impedance and propagation constant at the resonance frequencies corresponding to the line length. Thus, resonance-effect-free transmission line parameter determination technique based on the physical insight and theory is proposed. Then, by using the parameters high-frequency circuit model is proposed for high-speed signal propagation characterization. The proposed frequency-variant transmission line model is verified with measurement and it can be usefully exploited in high-speed signal propagation characterization.

• Journal of the Korean Society of Safety
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• v.29 no.6
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• pp.34-39
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• 2014

This paper is aimed to prevent danger of electrical fire at cattle barn to detect resistive and capacitive leakage current component for wiring type and length. In order to analysis for electric leakage component for cattle barn sizes and normal buildings, this paper was studied field state investigation which are at cattle barn companies(10 companies) in Cheong-won location and normal buildings at Nam-bu market in Jeon-ju location. Market to deduce the problems of electric leakage component is analyzed. The resistive and capacitive leakage current component for wiring type and length is analyzed at Beon-young cattle barn. Results show that electric leakage component suggested in this paper are valuable and usable to electrical fire in leakage current based on environment factor, which will prevent severe damage to human beings and properties and reduce the electrical fires in cattle barn. It is acceptable for electrical equipment use in an cattle barn.