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SDR(Software Defined Radio)에 적합한 네트워크 코프로세서 구조의 설계
김현필,정하영,함동현,이용석,Kim, Hyun-Pil,Jeong, Ha-Young,Ham, Dong-Hyeon,Lee, Yong-Surk 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.2A
디지털 컨버전스가 이루어지면서 무선기기들 간의 호환성은 단말기의 중요한 특성이 되었고, SDR은 가장 필요한 기술이고 표준이다. 하지만 통신 프로토콜이 다른 무선 환경에서 호환성을 갖는 단말기를 하드웨어만을 이용한 ASIC이나 SoC로 만들기는 어려운 실정이다. 그래서 본 논문은 여러 통신 프로토콜을 가속화 시킬 수 있는 코프로세서의 구조를 제안하였다. 메인 프로세서와 쉽게 연동이 되고, 네트워크의 PHY 레이어에 특화된 코프로세서가 바로 그것이다. 통신 시스템에서 가장 많이 사용하는 변조 방식인 OFDM과 CDM을 사용하는 무선 랜 표준 IEEE802.11a와 IEEE802.11b를 모델링한 C 프로그램을 ARM cross 컴파일러를 이용해 컴파일 하였고, Simplescalar-Arm 버전을 이용해 시뮬레이션 및 프로파일을 수행하였다. 프로파일 결과 비터비 연산과 부동 소수점 복소수 연산이 가장 많은 연산을 차지하였다. 프로파일 결과를 바탕으로 비터비 연산과 부동 소수점 복소수 연산을 가속화 할 수 있는 코프로세서를 제안하여 명령어를 추가했으며, 추가된 명령어는 Simplescalar-Arm 버전을 이용해 시뮬레이션 하였다. 시뮬레이션 결과 ARM 코어 하나만 사용 했을 때보다 비터비 연산은 약 4.5배, 부동 소수점 복소수 연산은 약 2배의 성능 향상을 보였다. IEEE802.11a에서는 일반 ARM 코어보다 약 3배의 성능 향상을 보였고, IEEE802.11b에서는 약 1.5배의 성능 향상의 보였다. In order to become ubiquitous world, the compatibility of wireless machines has become the significant characteristic of a communication terminal. Thus, SDR is the most necessary technology and standard. However, among the environment which has different communication protocol, it's difficult to make a terminal with only hardware using ASIC or SoC. This paper suggests the processor that can accelerate several communication protocol. It can be connected with main-processor, and it is specialized PHY layer of network The C-program that is modeled with the wireless protocol IEEE802.11a and IEEE802.11b which are based on widely used modulation way; OFDM and CDM is compiled with ARM cross compiler and done simulation and profiling with Simplescalar-Arm version. The result of profiling, most operations were Viterbi operations and complex floating point operations. According to this result we suggested a co-processor which can accelerate Viterbi operations and complex floating point operations and added instructions. These instructions are simulated with Simplescalar-Arm version. The result of this simulation, comparing with computing only one ARM core, the operations of Viterbi improved as fast as 4.5 times. And the operations of complex floating point improved as fast as twice. The operations of IEEE802.11a are 3 times faster, and the operations of IEEE802.11b are 1.5 times faster.
김현필,김용조,Kim, Hyun-Pil,Kim, Yong-Jo 한국금형공학회 2008 한국금형공학회지 Vol.2 No.4
Supplementary features in injection molded products, which are boss, rib and snap fit, are mainly located in the products. These features might make molding flow improper in injection processing and consequently give rise to some of molding troubles such as short shot and hesitation. The sink mark on boss parts is generated by the volumetric shrinkage that is caused by both the molding thickness and the closed boss height. The volumetric shrinkage is affected by packing pressure and its amount tends to decrease by increasing the packing pressure. The packing pressure can therefore increase flow rate to a boss part and causes the sink mark depth to increase. As the molding thickness and the closed boss height in the boss part can increase the part volume, these may yield bad solidifying and also extend the molding cycle. In this paper, both the injection molding test and the flow analysis were carried out to investigate the effect of sink marks generated in the boss part of injection molded products.
김현필(Hyun-Pil Kim) 산업기술교육훈련학회 2020 산업기술연구논문지 (JITR) Vol.25 No.2
The chip conveyor belt parts consist of progressively curled conveyor plates. Realizing the proper shape using progressive curling is difficult because bending and forming simultaneously are challenging. Therefore, this study aims to obtain the optimized design by performing progressive curling design through forming analysis in advance. The study examines the possibility of encountering sheet metal SM35C defects during progressive curling using forming analysis and reviews the damage value, distributions of the plastic effective strain, and residual effective stress. Moreover, the results set and applied the process number taken from the curling process of the chip conveyor belt parts are optimized by the sheet-metal forming analysis for an actual manufacturing process.
김현필(Hyun-Pil Kim),김종현(Jong-Hyeon Kim),김용조(Yohng-Jo Kim),김원일(Won-Il Kim) 산업기술교육훈련학회 2012 산업기술연구논문지 (JITR) Vol.17 No.1
The two color injection molding is recently used for production of IT parts. By this injection molding technology, the molded part in the first molding process is welded to the part molded by the second or third molding process into the final molded product. In this study, the rapid heat cycle molding system is applied to the two color injection molding and then the influence of the rapid heating and cooling cycle on the over injection molding was investigated by injection experiments. The injection trouble, weld line, flash, generated in the over injection molded parts was also investigated and commented upon. The rapid heating of the over injection mold can increase the time of heating and cooling and hence is mainly responsible for the increase of the two color injection molding cycle.
PBB-TE 망에서의 MPLS-TP 기반 Layer 2 연결 제어 프로토콜의 제안과 구현
김현필(Hyun-Pil Kim),최진식(Jin-Seek Choi) 대한전자공학회 2010 대한전자공학회 학술대회 Vol.2010 No.6
In this paper, we propose and implement a Multi-Protocol Label Switching-Transport Profile (MPLS-TP) based connection control protocol for Provider Backbone Bridge Transport Engineering (PBB-TE) network by using Openwrt[1] Linux.
열간공구강 DH32 소재의 열간단조품 개발에 관한 연구
장진형,김현수,김종현,김현필,김용조,Jang, Jin-Hyung,Kim, Hyun-Su,Kim, Jong-Hyeon,Kim, Hyun-Pil,Kim, Young-Jo 한국금형공학회 2012 한국금형공학회지 Vol.6 No.1
Hot tool steel, in general, has not been used as a material in hot forging. However such a hot tool steel is recently applied to forging materials by recent forging technology. DH32 is known as a kind of hot tool steels, which is developed for characteristics of excellent strength and toughness in high temperature. Feasibility of DH32 to hot forging material has been researched to develop the hot forging technology of a plunger used for a large-sized marine fuel pump. Hot compression experimental works were performed to investigate the hot strain characteristic of DH32 and with the experimental results FE simulations were also conducted for the design of forging processes and preform. It is found out through the hot compression experimental works that DH32 has a hot brittleness at more than $1150^{\circ}C$.
자동변속기 이너레이스 스플라인 치형의 정밀열간단조 공정에 관한 연구
김현수,이정환,김현필,김용조,강성훈,Kim, Hyun-Soo,Lee, Jung-Hwan,Kim, Hyun-Pil,Kim, Yong-Jo,Kang, Seong-Hoon 한국금형공학회 2012 한국금형공학회지 Vol.6 No.2
In this study, the hot forging technology for precision forming of spline teeth of the inner race in the auto-transmission was developed in order to minimize its finishing allowance. Several blocker and finisher shapes for the precision hot forging process of the inner race were proposed and the forging processes were analyzed using the three-dimensional finite element method. The optimum hot forging process was obtained considering some parameters such as metal flow patterns, forging defects and forming load. Blocker and finisher dies for the hot forging process were designed by selecting the most suitable shapes obtained from the finite element analysis. Experimental works were also performed in order to verify the optimum design of hot forging process.