• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2016년도 춘계학술대회
• /
• pp.174-177
• /
• 2016

네트워크-온-칩 (Network-on-Chip, NoC)에서 임계경로 문제를 개선하기 위해 라우터에 라디오 주파수 (RF) 모듈을 집적하는 무선 네트워크-온-칩(Wireless Network-on-Chip, WNoC)은 코어와 무선 인터페이스 라우터 (Wireless Interface Router, WIR)의 매핑 정보에 따라 통신량이 많은 코어간의 임계경로가 변화하여 지연시간에 악영향을 줄 수 있다. 본 논문에서는 코어들이 서브넷을 구성하는 small world 구조 WNoC에서 지연시간을 최적화하기 위해 코어 간의 통신량을 고려한 유전알고리즘(Genetic Algorithm, GA) 기반 코어 및 WIR의 매핑 기법을 제안하였다. 제안한 기법이 통신량이 많은 코어간의 임계경로를 최적화할 수 있도록 하였다. 모의실험 결과를 통해 무작위 매핑과 비교하여 제안하는 기법이 $4{\times}4$ 메시 기반 small world 구조에서 지연시간을 평균 33% 감소시키는 것을 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
• /
• pp.1081-1085
• /
• 2009

We have already developed EMI reducing techniques using lossless compression by vertically differential EMI suppression method (VDE[1]). It applies lossless modulo reduction and data bit mapping optimization for low voltage differential signaling (LVDS) transmission lines, that reduces the probability of transient bit and EMI by 12 dB [6][7]. We also improved and optimized the VDE for low power LCD interface. With this modified VDE algorithm[8], the developed FPGA was measured the reduction of the power consumption of LCD circuit by more than 15 % compared to the conventional methods in the case of 14-in LCD with SXGA resolution. The VDE algorithm is based on the total image systematic approach. In the VDE method, the present image signals are subtracted for the 1H delayed image signals and transferred to a column driver through a PCB. As the vertical correlations for image signals are very high, we expected that most of the vertically subtracted image signals remain 0 level and transient cycles become very long. As a result, the power consumption and EMI are extremely reduced for the transferred image signals on a PCB. In this paper, we discussed our proposed method by emphasizing the fact that systematic approach are important based on not only display point of view but also total system point of view.

• 대한전자공학회논문지SD
• /
• 제45권3호
• /
• pp.36-43
• /
• 2008

운영체제 수준의 전력 소모 최적화 기법에 대한 관심이 고조되고 있다. 운영체제는 시스템의 실행에 있어 종합적인 관리를 하기 때문에 시스템의 전력 소모에 막대한 영향을 미칠 수 있고, 이에 따라 전력 소모를 고려한 운영체제(Power Aware OS)에 대한 관심이 매우 높아지고 있다. 마이크로소프트, 인텔, 도시바 등의 회사에서 공동으로 제정한 ACPI 표준은 다양한 장치들의 전력관리를 BIOS/Firmware 수준이 아닌 운영체제 수준에서 효과적으로 고급 기법을 적용할 수 있도록 한다는 점에서 매우 효용성이 높은 것으로 평가받고 있다. 본 논문에서는 데스크탑, 노트북 플랫폼 기반의 ACPI를 임베디드 리눅스 시스템에 구현한 포팅 방법에 대하여 설명한다. 또한 구현 과정 중에 극복되어 왔던 기술적인 측면들에 대하여 고찰한다.

• 한국전기전자재료학회논문지
• /
• 제29권6호
• /
• pp.376-379
• /
• 2016

In this paper, the efficiency improvement of the heterojunction with intrinsic thin layer (HIT) solar cells is obtained by optimization process of p-type a-SiC:H as emitter. The optoelectronic of p-type a-SiC:H layers including the optical band-gap and conductivity under the methane gas content variation is conducted in detail. A significant increase in the Jsc by $1mA/cm^2$ and Voc by 30 mV are attributed to enhanced photon-absorption due to broader band-gap of p-a-SiC:H and reduced band-offsets at p-side interface, respectively of HIT solar cells.

• 동력기계공학회지
• /
• 제17권4호
• /
• pp.109-114
• /
• 2013

In this study, the microstructure, mechanical properties and high temperature oxidation characteristics of HiSiMo and HiSiMoM ductile iron for exhaust manifold were investigated. The HiSiMoM ductile iron was developed by optimization of alloying element addition and casting design. The exhaust manifold prototype was fabricated using the HiSiMoM iron and this resulted in the weight saving of 0.73kg. The microstructures of the HiSiMo and HiSiMoM irons were similar each other and graphite nodularity was 89% and 93% respectively. Tensile strengths of them were 663.5 and 674.4 MPa and Brinell hardness were 235.3 and 243.9 respectively. Both irons showed parabolic weight gain behavior in high temperature oxidation atmosphere. Oxidation layer was divided into external and internal layers. The weight gain of the HiSiMoM iron was lower than that of the HiSiMo iron after isothermal oxidation test at $900^{\circ}C$. This should be rationalized by higher Si enrichment at the interface of the matrix and internal layer of the HiSiMoM iron.

• 한국정밀공학회지
• /
• 제18권12호
• /
• pp.192-199
• /
• 2001

Chemical mechanical planarization (CMP) has emerged as the planarization technique of choice in both front-end and back-end integrated circuit manufacturing. Conventional CMP process utilize a polyurethane polishing pad and liquid chemical slurry containing abrasive particles. There hale been serious problems in CMP in terms of repeatability and deflects in patterned wafers. Especial1y, dishing and erosion defects increase the resistance because they decrease the interconnection section area, and ultimately reduce the lifetime of the semiconductor. Methods to reduce dishing & erosion have recently been interface hardness of the pad, optimization of the pattern structure as dummy patterns. Dishing & erosion are initially generated an uneven pressure distribution in the materials. These defects are accelerated by free abrasives and chemical etching. Therefore, it is known that dishing & erosion can be reduced by minimizing the abrasive concentration. Minimizing the abrasive concentration by using CeO$_2$is the best solution for reducing dishing & erosion and for removal rate. This paper introduce dishing & erosion generating mechanism and a method fur developing a semi-rigid abrasive pad to minimize dishing & erosion during CMP.

• 한국ITS학회 논문지
• /
• 제11권4호
• /
• pp.112-120
• /
• 2012

본 논문에서는 무선으로 비디오를 데이터 전송하여 접근하는데 필요한 스트림 시스템을 구현하여 시스템 내에서 발생하는 EMI(Electro Magnetic Interference) 잡음을 각 인터페이스, 회로 그리고 PCB(Printed Circuit Board) 상에서 주파수 대역별로 분석하였고 각각 기능 블럭에 대한 잡음 개선 방안을 제시하였다. 개선방안으로 저역통과 대역 필터링, 고속 데이터 라인들의 내층 배선, 그라운드의 최적화를 수행하였다. 구현된 시스템은 EMI 규제치 30 ~ 230[MHz]대역과 230 ~ 1000[MHz]대역에서 각각 40[dBuV/m]와 47[dBuV/m]내로 약 2 ~ 20[dB] 마진을 확보하여 잡음 개선을 하였다.

• 통합자연과학논문집
• /
• 제11권4호
• /
• pp.167-183
• /
• 2018

Electroencephalogram (EEG) recording provides a new way to support human-machine communication. It gives us an opportunity to analyze the neuro-dynamics of human cognition. Machine learning is a powerful for the EEG classification. In addition, machine learning can compensate for high variability of EEG when analyzing data in real time. However, the optimal EEG electrode location must be prioritized in order to extract the most relevant features from brain wave data. In this paper, we propose an intelligent system model for the extraction of EEG data by training the optimal electrode location of EEG in a specific problem. The proposed system is basically a fuzzy system and uses a neural network structurally. The fuzzy clustering method is used to determine the optimal number of fuzzy rules using the features extracted from the EEG data. The parameters and weight values found in the process of determining the number of rules determined here must be tuned for optimization in the learning process. Genetic algorithms are used to obtain optimized parameters. We present useful results by using optimal rule numbers and non - symmetric membership function using EEG data for four movements with the right arm through various experiments.

• Nuclear Engineering and Technology
• /
• 제51권4호
• /
• pp.968-976
• /
• 2019

This paper presents a number of verification case studies for a recently developed sensitivity/uncertainty code package. The code package, ROMUSE (Reduced Order Modeling based Uncertainty/Sensitivity Estimator) is an effort to provide an analysis tool to be used in conjunction with reactor core simulators, in particular the Virtual Environment for Reactor Applications (VERA) core simulator. ROMUSE has been written in C++ and is currently capable of performing various types of parameter perturbations and associated sensitivity analysis, uncertainty quantification, surrogate model construction and subspace analysis. The current version 2.0 has the capability to interface with the Design Analysis Kit for Optimization and Terascale Applications (DAKOTA) code, which gives ROMUSE access to the various algorithms implemented within DAKOTA, most importantly model calibration. The verification study is performed via two basic problems and two reactor physics models. The first problem is used to verify the ROMUSE single physics gradient-based range finding algorithm capability using an abstract quadratic model. The second problem is the Brusselator problem, which is a coupled problem representative of multi-physics problems. This problem is used to test the capability of constructing surrogates via ROMUSE-DAKOTA. Finally, light water reactor pin cell and sodium-cooled fast reactor fuel assembly problems are simulated via SCALE 6.1 to test ROMUSE capability for uncertainty quantification and sensitivity analysis purposes.

• The Journal of Advanced Prosthodontics
• /
• 제14권3호
• /
• pp.182-202
• /
• 2022

PURPOSE. The aim of this study is to summarize various biomechanical aspects in evaluating the long-term stability of dental implants based on finite element method (FEM). MATERIALS AND METHODS. A comprehensive search was performed among published studies over the last 20 years in three databases; PubMed, Scopus, and Google Scholar. The studies are arranged in a comparative table based on their publication date. Also, the variety of modeling is shown in the form of graphs and tables. Various aspects of the studies conducted were discussed here. RESULTS. By reviewing the titles and abstracts, 9 main categories were extracted and discussed as follows: implant materials, the focus of the study on bone or implant as well as the interface area, type of loading, element shape, parts of the model, boundary conditions, failure criteria, statistical analysis, and experimental tests performed to validate the results. It was found that most of the studied articles contain a model of the jaw bone (cortical and cancellous bone). The material properties were generally derived from the literature. Approximately 43% of the studies attempted to examine the implant and surrounding bone simultaneously. Almost 42% of the studies performed experimental tests to validate the modeling. CONCLUSION. Based on the results of the studies reviewed, there is no "optimal" design guideline, but more reliable design of implant is possible. This review study can be a starting point for more detailed investigations of dental implant longevity.