• 한국컴퓨터정보학회논문지
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• 제20권11호
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• pp.1-8
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• 2015

Flash memory has advantages in that it is fast access speed, low-power, and low-price. Therefore, they are widely used in electronics industry sectors. However, the flash memory has weak points, which are the limited number of erase operations and non-in-place update problem. To overcome the limited number of erase operations, many wear leveling techniques are studied. They use many tables storing information such as erase count of blocks, hot and cold block indicators, reference count of pages, and so on. These tables occupy some space of main memory for the wear leveling techniques. Accordingly, they are not appropriate for low-power devices limited main memory. In order to resolve it, a wear leveling technique using bit array and Bit Set Threshold (BST) for flash memory. The proposing technique reduces the used space of main memory using a bit array table, which saves the history of block erase operations. To enhance accuracy of cold block information, we use BST, which is calculated by using the number of invalid pages of the blocks in a one-to-many mode, where one bit is related to many blocks. The performance results illustrate that the proposed wear leveling technique improve life time of flash memory to about 6%, compared with previous wear leveling techniques using a bit array table in our experiment.

• Advances in pediatric surgery
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• 제4권2호
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• pp.110-116
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• 1998

This is a clinical review of 2,191 pediatric surgical patients under the age of 15 years, operated upon at the Division of Pediatric Surgery, Department of Surgery, Chonnam University Hospital from January 1988 to December 1997. The total number of operations in the pediatric age for all specialties were 13,144(13.2 %). The total operations including those performed on adults were 99,555. The most common age group operated upon was under 5 year of age(44.4 %). The number of operations in Division of General Pediatric Surgery were 2,191(16.7 %) out of total 13,144 operations in all pediatric specialties. The patients under 1 year of age in general pediatric surgery was 42.9 %(941/2,191). The most common diseases in neonates were anorectal malformation(20.6 %) and hypertrophic pyloric stenosis(20.3 %). Infants older than neonates most commonly were operated upon for inguinal hernia(32.4 %) and intussusception(19.6 %). The total mortality rate in the neonatal intensive care unit was 31.3 %. Gastroschisis had the highest mortality.

• ETRI Journal
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• 제33권2호
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• pp.267-274
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• 2011

This paper proposes an efficient masking method for the block cipher SEED that is standardized in Korea. The nonlinear parts of SEED consist of two S-boxes and modular additions. However, the masked version of these nonlinear parts requires excessive RAM usage and a large number of operations. Protecting SEED by the general masking method requires 512 bytes of RAM corresponding to masked S-boxes and a large number of operations corresponding to the masked addition. This paper proposes a new-style masked S-box which can reduce the amount of operations of the masking addition process as well as the RAM usage. The proposed masked SEED, equipped with the new-style masked S-box, reduces the RAM requirements to 288 bytes, and it also reduces the processing time by 38% compared with the masked SEED using the general masked S-box. The proposed method also applies to other block ciphers with the same nonlinear operations.

• 한국식생활문화학회지
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• 제15권2호
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• pp.69-78
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• 2000

The purposes of this study were to : (a) investigate overall operating conditions of university residence hall foodservice, (b) compare them by the management systems. Questionnaires were hand delivered and mailed to 73 foodservice managers. A total of 56 were usable; resulting in 76.7% response rate. The survey was conducted between October, 1998 and May, 1999. Statistical data analysis was completed using the SAS/Win 6.12 for Descriptive Analysis, $x^2-test$. Sixty-four percent of the foodservice operations were 'self-operated'; 23% were 'contracted'; and 13% were 'rented'. Eighty-three percent of operations provided 'single menu'; forty-six percent of foodservice operations with 'partially self-service'; and forty-one percent with 'complete self-service'. Forty-four percent of overall foodservice operations provided 1,000-2,000 meals per day; thirty-one percent provided less than 1,000 meals per day, and twenty-four percent provided more than 2,000 meals per day. The highest meal price was 1,950 won and the lowest was 700 won with average of 1,295 won. The mean number of employees was 12.2; the number of working hours was 59.7 hours per week.

• East Asian mathematical journal
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• 제19권1호
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• pp.17-26
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• 2003

This paper demonstrates the CAS technique of analyzing the nature and the structure of the numerical error for education and research purposes. This also illustrates the CAS approach in experimenting with the numerical operations in an arbitrary computer number system and also in doing error analysis in a visual manner.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2008년도 추계학술대회 및 정기총회
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• pp.353-358
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• 2008

The ocean has settled down in human mind as a territory and a leisure space from which anyone enjoys and takes a benefit under the national sovereignty, as the new era of Sea comes. In addition, because the population engaged in marine activities has rapidly increased, the number of marine accidents consequently has grown up as well. In this reason, currently it has been highlighted to devise safety measures to prevent large scale accidents or disasters on the oceans. Therefore, this thesis firstly points out issues and problems of current search and rescue operations, and secondly studies three primary factors of the search and rescue operations, which are decision of search range, decision of search asset, and decision of search duration. Finally, the thesis suggests a theoretical foundation of the search and rescue operations by applying the result of studies and the marine search theory through a theoretical approach to reasonable standards.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제7권3호
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• pp.205-208
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• 2007

Measuring the similarity between fuzzy sets plays a vital role in several fields. However, none of all well-known similarity measure methods is all-powerful, and all have the localization of its usage. This paper defines some operations on the similarity measures of fuzzy sets such as summation and multiplication of two similarity measures. Also, these operations will be generalized to any number of similarity measures. These operations will be very useful especially in the field of computer vision, and data retrieval because these fields need to combine and find some relations between similarity measures.

• ETRI Journal
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• 제38권2호
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• pp.326-336
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• 2016

We propose and describe new error control algorithms for redundant residue number systems (RRNSs) and residue number system product codes. These algorithms employ search techniques for obtaining error values from within a set of values (that contains all possible error values). For a given RRNS, the error control algorithms have a computational complexity of $t{\cdot}O(log_2\;n+log_2\;{\bar{m}})$ comparison operations, where t denotes the error correcting capability, n denotes the number of moduli, and ${\bar{m}}$ denotes the geometric average of moduli. These algorithms avoid most modular operations. We describe a refinement to the proposed algorithms that further avoids the modular operation required in their respective first steps, with an increase of ${\lceil}log_2\;n{\rceil}$ to their computational complexity. The new algorithms provide significant computational advantages over existing methods.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제26권1호
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• pp.85-108
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• 2012

본 연구의 목적은 도형 영역과 수와 연산 영역에서 나타나는 초등학교 3학년 학생들의 정당화 유형에 대한 반응과 오류 유형을 검사하여 학생들의 정당화 지도에 대한 시사점을 제공하는 것이다. 연구 결과는 다음과 같다. 첫째, 수와 연산 영역에서 학생들은 정당화 유형 검사지를 해결함에 있어서 경험적 정당화 유형과 분석적 정당화 유형을 고루 사용했다. 둘째, 도형 영역에서는 분석적 정당화에 비해 경험적 정당화 비율이 높게 나타났는데, 경험적 정당화와 분석적 정당화의 비율이 고루 나타난 수와 연산 영역과의 차이가 있었다. 셋째, 정당화 과정에서 발생한 학생들의 오류를 분석해 본 결과 풀이과정 생략의 오류, 개념 및 원리의 오류, 문항 이해의 오류, 기술적 오류의 순으로 나타났다. 따라서 특히 도형 영역에서는 학생들에게 경험적 정당화는 물론이고 분석적 정당화에 대한 경험을 많이 제공할 필요가 있다. 또한 학생들의 오개념 및 잘못 이해하고 있는 원리를 정확하게 파악하여 재지도할 필요가 있겠다.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
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• pp.311-314
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• 2004

The 2 DBPP(Two-Dimensional Bin Packing Problem) is a problem of packing each item into a bin so that no two items overlap and the number of required bins is minimized under the set of rectangular items which may not be rotated and an unlimited number of identical rectangular bins. The 2 DBPP is strongly NP-hard and finds many practical applications in industry. In this paper we discuss a tabu search approach which includes tabu list, intensifying and diversification strategies. The HNFDH(Hybrid Next Fit Decreasing Height) algorithm is used as an internal algorithm. We find that use of the proper parameter and function such as maximum number of tabu list and space utilization function yields a good solution in a reduced time. We present a tabu search algorithm and its performance through extensive computational experiments.