• 한국산업정보학회논문지
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• 제18권1호
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• pp.25-35
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• 2013

Automatically deriving only individual don't-care minterms that can effectively reduce a Boolean logic expressions are being investigated. Don't-care conditions play an important role in optimizing logic design. The type of unknown don't-care minterms that can always reduce the number of product terms in Boolean expression are referred as single hypothetical don't-care (S-HDC) minterms. This paper describes the Quasi Quine-McCluskey method that systematically derives S-HDC minterms. For the most part, this method is similar to the original Quine-McCluskey method in deriving the prime implicants. However, the Quasi Quine-McCluskey method further derives S-HDC minterms by applying so-called a combinatorial comparison operation. Upon completion of the procedure, the designer can review generated S-HDC minterms to test its appropriateness for a particular application.

• 대한전자공학회논문지SD
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• 제37권3호
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• pp.48-54
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• 2000

이 논문은 임베디드 소프트웨어를 위한 소프트웨어 합성시 don't care 정보를 이용하여 합성된 소프트웨어의 성능을 향상시키기 위한 방법을 제시한다. 임베디드 시스템은 주로 실시간 처리가 요구되는 분야에 사용되기 때문에 매우 까다로운 실시간 및 코드 크기의 제한이 있기 때문에 그에 관한 최적화는 매우 중요하다. 우리는 BDD 기반의 유한상태기계 전달 함수의 표현으로부터 확장된 유한상태기계를 유도하는 소프트웨어 합성의 경우에 돈 케어정보를 추출하고, 그를 이용한 BBD를 최소화하여, 일차적으로는 코드크기를 줄이고 결과적으로는 코드가 실행되는 임베디드 시스템의 성능을 향상시키는 방법을 제안한다. 그러한 방법이 적용된 실험적 결과를 제시하고, don't care 기반의 BDD 최소화와 BDD 변수의 동적 재배열의 결합 등 관련 연구 방향을 제안한다.

• 디지털콘텐츠학회 논문지
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• 제18권5호
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• pp.881-888
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• 2017

다중화기를 이용한 논리설계는 구조적 디지털 시스템 설계에서 설계의 편리성과 유연성을 위한 유용한 방법으로 사용되어왔다. 본 논문에서는 다중화기(multiplexer : MUX) 기반 논리설계에서 종래의 연구들에서 세밀히 다루지 않았던 무정의 조건(don't care condition)이 논리최적화에 미치는 영향을 분석해보고 단일 다중화기 기반의 설계와 복수 다중화기 기반의 설계를 위한 무정의 조건의 활용방법을 제시한다. 특히 데이터 입력의 개수가 $2^m$개보다 적은 경우(선택선의 개수는 m개일 때)의 설계방법을 고찰한다. 제시하는 기법을 디지털논리설계 교육과 관련하여 최근 창의적 공학교육에서 크게 활용되고 있는 아두이노(Arduino)를 이용한 마이크로프로세서 설계와 연계하여 활용하는 방법에 대해서도 기술한다.

• 전자공학회논문지C
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• 제36C권9호
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• pp.20-27
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• 1999

BDD는 논리합성 응용분야에서 많이 이용되는 데이터 구조체이다. 불완전하게 표시된 함수를 합성할 때, BDD의 크기를 최소화할 수 있으면 BDD의 구조를 따라 만들어지는 회로의 크기나 동작 속도를 향상시키는 데 큰 잇점이 있다. 본 논문에서는 논리합성을 위해 don't care를 이용하여 BDD를 최소화하기 위한 두 가지 알고리즘을 소개하고자 한다. 실험결과 제안된 방법은 기존 방법에 비해 수행시간의 희생 없이 더욱 작은 크기의 BDD을 얻을 수 있었다.

• ETRI Journal
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• 제24권6호
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• pp.473-476
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• 2002

This letter proposes an efficient kernel-based partitioning algorithm for reducing area and power dissipation in combinational circuit designs using don't-care sets. The proposed algorithm decreases power dissipation by partitioning a given circuit using a kernel extracted from the logic. The proposed algorithm also reduces the area overhead by minimizing duplicated gates in the partitioned sub-circuits. The partitioned subcircuits are further optimized utilizing observability don't-care sets. Experimental results for the MCNC benchmarks show that the proposed algorithm synthesizes circuits that on the average consume 22.5% less power and have 12.7% less area than circuits generated by previous algorithms based on a precomputation scheme.

• 한국패션뷰티학회지
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• 제1권1호
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• pp.49-64
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• 2003

A study on skin care of middle-aged women was conducted to develop proper skin care program. The study was performed from January 25, 2003 through March 24, 2003 by using questionnaires. The subjects were 380 from some area in Youngnam province. All subjects were females from 40 to 59 years. The results of this study are summarized as follows. 1. According to general characteristics of the subjects, 36.8% of them was from 40 to 44years old; 61.3% 'high school graduate' ; 61.1% 'housewife';89.2% 'married' ;76.1% 'middle class' ;55.8% 'living in small or medium sized city'. In the case of physical health conditions, 55.8% of the respondents was in good health and 63.9% answered that their face skins were healthy. Those who don't drink were 54.5%, and those who don't smoking were 92.9%. 2. In case of the knowledge level of skin care, it showed significant difference in the variables of education, occupation, and economic status. According to the knowledge level of skin care by physical health conditions, it was highest in the case of physically healthy respondents(7.77 point). Those who do not smoke marked higher knowledge level of skin care than those who smoke. Those who exercise also marked higher knowledge level of skin care, than those who don't exercise. 3. 86.8% of the subjects experienced the massage at home. It showed significant difference in the variable of education and place of residence. The knowledge and habit of skin care of middle-aged women showed significant difference according to the variable of education, economic status, and place of residence. Therefore, related professionals and organizations relating to the skin care must make efforts to develop education program for effective skin care for middle-aged women in order to enhance the knowledge level of skin care and information about skin health.

• 대한전기학회논문지:시스템및제어부문D
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• 제49권2호
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• pp.81-87
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• 2000

This paper presents a new approach to the synthesis of two-dimensional arrays such as Atmel 6000 series FPGAs using internal don't cares. Basically complex terms which fits to the linear array of cells without further routing wires are generated and they are collected by OR/XOR operations. In previous methods, complex terms are collected only by XOR operations, which may not be effective for nearly unate functions. In this paper, we allow complex terms to be collected by OR operations in addition to XOR operations. First, complex terms that lies in the ON-set of the function are generated and collected by OR operations. The sub-function realized by the first stage becomes an internal don't cares and they are exploited in the second stage which generates complex terms collectable by XOR operation. Experimental results shows the efficacy of the proposed method compared to the previous methods.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.690-692
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• 2012

본 논문에서는 IP 코어(core)의 스캔 테스트(scan test)에 있어서 테스트 전력소모를 고려한 효율적인 테스트 데이터 압축방법을 제안한다. 스캔 슬라이스(Scan slice)의 선택적 부호화를 이용한 테스트 데이터 압축에 대한 연구는 많이 진행되어 왔으나 전력소모를 고려하진 않았다. 스캔 슬라이스의 don't care에 값을 할당할 때, 이웃한 슬라이스와 해밍거리가 최소화 되도록 값을 할당하여 스위칭 전력소모가 최소가 되도록 하였다. 테스트 회로에 적용하여 알고리즘을 검증하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.597-598
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• 2008

In this paper, a sample design of I/O port of micro-processor using ODC(Output Don't Care) computation that is one of methods for Clock Gating applicable at the register transfer level(RTL). The ODC computation Method is applied at the point that estimate the value considering Don't Care Conditions from output of datapath to registers using clock in logic system. This paper also shows the results of reduce consumption power due to controlling clock that was supplied at registers. In Experimental results, ODC computation Method reduce power reductions of around 37.5%

• 대한가정학회지
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• 제37권2호
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• pp.85-98
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• 1999

The purpose of this study is to identify the preferences for care type among the elderly and to analyze contributing variables. The sample in this study are 485 elder people who are age 55 and over. The independent variables are divided into five factors according to their characteristics, and the dependent variables fall into two categories of private and public care types. The descriptive statistics and Logistic Regression method are employed for the analysis. The results can be summarized as follows. The elderly prefer individual care paid for by their own support to the other types like the care by children or institution. However, the elderly stiff like and expect family care by their children. The variables that haute affected the preferences of the care types among the elderly are whether they are employed or not, household's the amount of debt, whether they currently live with the oldest child, their level of self esteem and their degree of satisfaction in life. The results show that the elderly don't have various wants or alternatives to their care and regard public care as negative support for the financially incapable or the elderly who have no relatives.