• Title/Summary/Keyword: Digital Sum Value

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A MaxMin Model for the Worst Case Performance Evaluation of GS Coding for DC-free Modulation (DC-억압 변조를 위한 GS 코딩의 최악 성능 평가 MaxMin 모형)

  • Park, Taehyung;Lee, Jaejin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.8
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    • pp.644-649
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    • 2013

  • For effective DC-free coding in the optical storage systems, the Guided Scrambling algorithm is widely used. To reduce digital discrepancy of the coded sequence, functions of digital sum value (DSV) are used as criteria to choose the best candidate. Among these criteria, the minimum digital sum value (MDSV), minium squared weight (MSW), and minimum threshold overrun (MTO) are popular methods for effective DC-suppression. In this paper, we formulate integer programming models that are equivalent to MDSV, MSW, and MTO GS coding. Incorporating the MDSV integer programming model in MaxMin setting, we develop an integer programming model that computes the worst case MDSV bound given scrambling polynomial and control bit size. In the simulation, we compared the worst case MDSV bound for different scrambling polynomial and control bit sizes. We find that careful selection of scrambling polynomial and control bit size are important factor to guarantee the worst case MDSV performance.

  • https://doi.org/10.7840/kics.2013.38A.8.644 인용 PDF KSCI

Novel User Selection Algorithm for MU-MIMO Downlink System with Block Diagonalization (Block Diagonalization을 사용하는 하향링크 시스템에서의 MU-MIMO 사용자 스케쥴링 기법)

  • Kim, Kyunghoon
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.14 no.3
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    • pp.77-85
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    • 2018

  • Multi-User Multiple-Input Multiple-Output (MU-MIMO) is the core technology for improving the channel capacity compared to Single-User MIMO (SU-MIMO) by using multiuser gain and spatial diversity. Key problem for the MU-MIMO is the user selection which is the grouping the users optimally. To solve this problem, we adopt Extreme Value Theory (EVT) at the beginning of the proposed algorithm, which defines a primary user set instead of a single user that has maximum channel power according to a predetermined threshold. Each user in the primary set is then paired with all of the users in the system to define user groups. By comparing these user groups, the group that produces a maximum sum rate can be determined. Through computer simulations, we have found that the proposed method outperforms the conventional technique yielding a sum rate that is 0.81 bps/Hz higher when the transmit signal to noise ratio (SNR) is 30 dB and the total number of users is 100.

  • https://doi.org/10.17662/ksdim.2018.14.3.077 인용 PDF KSCI

Automated Visual Inspection System of Double Gear using Inspection System (더블기어 자동 시각 검사 시스템 실계 및 구현)

  • Lee, Young Kyo;Kim, Young Po
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.7 no.4
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    • pp.81-88
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    • 2011

  • Mini Double Gears Frame is critical part of PDP and also produces couple hundred thousand every month. In the process of mass production, product inspection is very important process. Double Gear, one of the part of machine, was inspected by human eyes which caused mistakes and slow progress. To achieve the speed and accuracy the system was compensated by vision system which is inspecting automatically. The focus value is measured based on the fact that high contrast images have much high frequency edge information. High frequency term of the image is extracted using the high-pass filter and the sum of the high frequency term is used as the focus value. We used a Gaussian smoothing filter to reduce the noise and then measures the focus value using the modified Laplacian filter called a Sum modified Laplacian Focus values for the various lens positions are calculated and the position with the maximum focus value is decided as the focused position. The focus values calculated in various lens position showed the Gaussian distribution. We proposed a method to estimate the best focus position using the Gaussian curve fitting. Focus values of the uniform interval lens positions are calculated and the values are used to estimate the Gaussian distribution parameters to find the best focus position.

  • https://doi.org/10.17662/ksdim.2011.7.4.081 인용 PDF KSCI

A Clipping-free Multi-bit $\Sigma\Delta$ Modulator with Digital-controlled Analog Integrators (디지털 제어 적분형의 차단 현상이 없는 A/D 다중 비트 $\Sigma\Delta$ 변조기)

  • 이동연;김원찬
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.34C no.4
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    • pp.26-35
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    • 1997

  • This paper proposes a multi-bit $\Sigma\Delta$ modulator arcitecture which eliminates signal clipping problem. To avoid signal clipping, the output values of intgrators are monitored and modified by a reference value. This oepration is recorded as a digital code to restore actual signal value. Due to the digital code, the substraction of feedback value from the multi-bit quantizer can be calculated by a digital adder and this simplifies dAC operation making the accurate DAC of conventional multi-bit $\Sigma\Delta$ modulator scheme unnecessary. These features make N-th modulator can be implemented by sharing an integrator among N stages to decrease the required chip area. As an experimental example, a 4th order .sum..DELTA. modulator with oversampling ratio of 64 was simulated to show over 130 DB SNR at rail-to-rail input sinusoidal signal.

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A Study on the Optimized Architectural Space Planning by Searching Algorithm Method (탐색적 방법에 의한 건축공간 배치계획 최적화에 대한 고찰)

  • Lim, Myung-Gu;Kim, Su-Young
    • Journal of The Korean Digital Architecture Interior Association
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    • v.1 no.1
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    • pp.51-58
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    • 2001

  • The purpose of this study is to improve productivity of architectural space planning(A.S.P,) by computer system and to optimize ASP. A searching algorithm is the best way to slave optimized A.S.P. Because architectural design is too many various site situations and client's demands to specify the general solving methods. This method seek the best design case in all possibility and to be modeled as this; $\rightarrow$[$\rightarrow$$\rightarrow$