• Title/Summary/Keyword: Multi-Rate

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A Case Study on the Process Planning for Multi-Stepped Deep Drawing of Complex Circular Shells (원통형 용기의 다단계 \ulcorner드로잉 공정설계에 관한 사례 연구)

  • 김두환
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1998.03a
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    • pp.160-167
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    • 1998
  • This article is aimed primarily at establishing a process planning method for complex circular shells. For the deep drawing of complex shaped shell, the optimum process design is required to reduce the trial cost, improve the quality, increase the productivity and shorten the delivery. The present approach which is related to the optimum process planning is based on the empirical knowledge through trial and error in the industrial field. In order to check the validity and the effectiveness of proposed work, a sample process design has been applied to the multi-stepped deep drawing of complex shell considering the process variables such as drawing rate, radius and blank development. In particular, the difference between the limiting drawing rate and the optimum drawing rate has been discussed and has been shown the usefulness of present suggestion.

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A Power Control Scheme for Improving Secrecy Rate in Multi-Cell Uplink Networks (다중셀 상향링크 네트워크에서 기밀 전송률 향상을 위한 전력조절 기법)

  • Bang, Inkyu;Jung, Bang Chul;Sung, Dan Keun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.42 no.1
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    • pp.39-41
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    • 2017
  • In this letter, we propose a power control mechanism in order to improve secrecy rate defined as the difference between capacity of main link and wiretap link in a wireless multi-cell multiuser network. Through simulations, we verify that the proposed power control mechanism with threshold based user scheduling can significantly increase secrecy rate in a multi-cell environment.

TWO-LAYER MUTI-PARAMETERIZED SCHWARZ ALTERNATING METHOD

  • Kim, Sang-Bae
    • Journal of applied mathematics & informatics
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    • v.9 no.1
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    • pp.101-124
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    • 2002
  • The convergence rate of a numerical procedure barred on Schwarz Alternating Method (SAM) for solving elliptic boundary value problems (BVP's) depends on the selection of the interface conditions applied on the interior boundaries of the overlapping subdomains. It hee been observed that the Robin condition(mixed interface condition), controlled by a parameter, can optimize SAM's convergence rate. Since the convergence rate is very sensitive to the parameter, Tang[17] suggested another interface condition called over-determined interface condition. Based on the over-determined interface condition, we formulate the two-layer multi-parameterized SAM. For the SAM and the one-dimensional elliptic model BVP's, we determine analytically the optimal values of the parameters. For the two-dimensional elliptic BVP's , we also formulate the two-layer multi-parameterized SAM and suggest a choice of multi-parameter to produce good convergence rate .

Cooperative MAC Protocol Using Active Relays for Multi-Rate WLANs

  • Oh, Chang-Yeong;Lee, Tae-Jin
    • Journal of Communications and Networks
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    • v.13 no.5
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    • pp.463-471
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    • 2011
  • Cooperative communications using relays in wireless networks have similar effects of multiple-input and multiple-output without the need of multiple antennas at each node. To implement cooperation into a system, efficient protocols are desired. In IEEE 802.11 families such as a/b/g, mobile stations can automatically adjust transmission rates according to channel conditions. However throughput performance degradation is observed by low-rate stations in multi-rate circumstances resulting in so-called performance anomaly. In this paper, we propose active relay-based cooperative medium access control (AR-CMAC) protocol, in which active relays desiring to transmit their own data for cooperation participate in relaying, and it is designed to increase throughput as a solution to performance anomaly. We have analyzed the performance of the simplified AR-CMAC using an embedded Markov chain model to demonstrate the gain of AR-CMAC and to verify it with our simulations. Simulations in an infrastructure network with an IEEE 802.11b/g access point show noticeable improvement than the legacy schemes.

Modeling of a Multi-Leaf Spring for Dynamic Characteristics Analysis of a Large Truck (대형트럭 동특성 해석을 위한 다판 스프링의 모델링)

  • Moon Il Dong;Oh Seok Hyung;Oh Chae Youn
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.10
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    • pp.147-153
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    • 2004
  • This paper presents an analytical modeling technique fer representing a hysteretic behavior of a multi-leaf spring used for a large truck. It divides a nonlinear hysteretic curve of the multi-leaf spring into four parts; loading part, unloading part and two transition parts. It provides conditions fur branching to a part of the curve corresponding to a current multi-leaf spring status. This paper also presents a computational modeling technique of the multi-leaf spring. It models the multi-leaf spring with three links and a shackle. It assumes those components as rigid bodies. The links are connected by rotational joints, and have rotational springs at the joints. The spring constants of the rotational springs are computed with a force from the analytical model of the hysteretic curve of the multi-leaf spring. Static and dynamic tests are performed to verify the reliability of the presented techniques. The tests are performed with various amplitudes and excitation frequencies. The hysteretic curves from the tests are compared with those from the simulations. Since th e presented techniques reproduce the hysteretic characteristic of the multi -leaf spring faithfully, they contribute on improving the reliability of the computational model of a large truck.

Real-Time DSP Implementation of Adaptive Multi-Rate with TMS320C542 board (TMS320C542보드를 이용한 Adaptive Multi-Rate 음성부호화기의 실시간 구현)

  • 박세익;전라온;이인성
    • Proceedings of the IEEK Conference
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    • 2000.09a
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    • pp.827-830
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    • 2000
  • 3GPP and ETSI adopted AMR(Adaptive Multi-Rate) as a standard for next generation IMT-2000 service. In this paper, we analyzed algorithm about AMR and optimized ANSI C source on the C complier and assembly language of Texas Instrument . The implemented AMR speech codec requires 28.2MIPS of complexity for encoder and 5.5MIPS for decoder. we performed real-time implementation of AMR speech codec using 82% of TMS320C5402 with 40 MIPS specification. We give proof that the output speech of the implemented speech codec on DSP board is identical with result of C source program simulation. Also the reconstructed speech is verified in the real-time environment consisted of microphone and speaker.

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Effect of Thermal Stratification for Reducing Pressure Rise Rate in HCCI Combustion Based on Multi-zone Modeling (Multi Zone Modeling을 이용한 온도 성층화의 효과를 갖는 예혼합압축자기착화엔진의 압력상승률 저감에 대한 모사)

  • Kwon, O-Seok;Lim, Ock-Taeck
    • Transactions of the Korean Society of Automotive Engineers
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    • v.17 no.4
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    • pp.32-39
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    • 2009
  • The HCCI engine is a next generation engine, with high efficiency and low emissions. The engine may be an alternative to SI and DI engines; however, HCCI's operating range is limited by an excessive rate of pressure rise during combustion and the resulting engine knock in high-load. The purpose of this study was to gain a understanding of the effect of only initial temperature and thermal stratification for reducing the pressure-rise rate in HCCI combustion. And we confirmed characteristics of combustion, knocking and emissions. The engine was fueled with Di-Methyl Ether. The computations were conducted using both a single-zone model and a multi-zone model by CHEMKIN and modified SENKIN.

Reference Vector Diversity of Subspace Interference Alignment in Multi-cell Multi-user Uplink Systems (부분공간 간섭 정렬을 이용한 다중 셀 상향링크 시스템에서 합용량 향상을 위한 레퍼런스 벡터 다이버서티)

  • Seo, Jong-Pil;Lee, Yoon-Ju;Kwon, Dong-Seung;Lee, Myung-Hoon;Chung, Jae-Hak
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.47 no.7
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    • pp.23-28
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    • 2010
  • We propose a reference vector diversity method in multi-cell multi-user uplink system with the subspace interference alignment to obtain higher sum rate capacity. The proposed method transmits several reference vectors before the data transmission, and selects the best reference vector to maximize the cell sum rate. The proposed method provides higher sum-rate capacity compared with the previous interferenc alignment. Simulation result exhibits the proposed method improves the sum-rate capacity by 60%.

The Characteristics and the Type Classification of Contemporary Public Libraries in terms of browsing circuit (현대 공공도서관의 회로경험에 따른 유형분류 및 특성)

  • Lee, Soo-Kyung;Kim, Yong-Seung
    • Korean Institute of Interior Design Journal
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    • v.17 no.3
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    • pp.59-67
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    • 2008
  • This study aims to find out the characteristics and the type classification of contemporary public libraries in terms of browsing circuit. In so doing, it is to analyze 21 recently built libraries by using the browsing circuit, the spatial depth and the spatial layout. The study makes use of codes derived from the concept of 'Classification' and 'Frame' suggested by a pedagogist, Basil Bernstein. As a result, it shows that two codes are phased in overseas cases. In other words, one type is a lower depth of space and a high rate of rings with the multi-layer circuits and the three-dimensional circuit of multi-centered. the other type is the higher depth of space and a low rate of rings with the single-layer circuit and the multi-layer circuit of single-centered. In domestic cases, 4 types are shown. The characteristics of layout are seen as a radial shape and the rate of rings is lower than the overseas cases. It can be said that these results are a transitional phenomenon. For browsing circuit, domestic public libraries would be adapted to the three-dimensional circuit of multi-centered, a lower depth of space and a high rate of rings. By instructions of this plan, the real meaning of a public library will be come true.

New Methodology to Develop Multi-parametric Measure of Heart Rate Variability Diagnosing Cardiovascular Disease

  • Jin, Seung-Hyun;Kim, Wuon-Shik;Park, Yong-Ki
    • International Journal of Vascular Biomedical Engineering
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    • v.3 no.2
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    • pp.17-24
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    • 2005
  • The main purpose of our study is to propose a new methodology to develop the multi-parametric measure including linear and nonlinear measures of heart rate variability diagnosing cardiovascular disease. We recorded electrocardiogram for three recumbent postures; the supine, left lateral, and right lateral postures. Twenty control subjects (age: $56.70{\pm}9.23$ years), 51 patients with angina pectoris (age: $59.98{\pm}8.41$ years) and 13 patients with acute coronary syndrome (age: $59.08{\pm}9.86$ years) participated in this study. To develop the multi-parametric measure of HRV, we used the multiple discriminant analysis method among statistical techniques. As a result, the multiple discriminant analysis gave 75.0% of goodness of fit. When the linear and nonlinear measures of HRV are individually used as a clinical tool to diagnose cardiac autonomic function, there is quite a possibility that the wrong results will be obtained due to each measure has different characteristics. Although our study is a preliminary one, we suggest that the multi-parametric measure, which takes into consideration the whole possible linear and nonlinear measures of HRV, may be helpful to diagnose the cardiovascular disease as a diagnostic supplementary tool.

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