• 한국정보과학회논문지:시스템및이론
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• 제33권9호
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• pp.634-641
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• 2006

플래시 메모리는 비휘발성이며 빠른 I/O 처리 속도와 같은 많은 장점들이 있으나, in-placeupdate가 불가능하고 읽기/쓰기/지우기 작업의 속도가 다르다는 단점을 지니고 있다. 버퍼 캐시를 통해 플래시 메모리 기반 저장장치의 성능을 향상시키기 위해서는 수행 속도가 느림은 물론 지우기 작업의 수행 횟수에 직접적인 영향을 끼치는 쓰기 작업의 횟수를 줄이는 알고리즘이 필요하다. 본 논문에서는 기존의 LRU 버퍼교체 정책에 not-cold-dirty-page에 대한 교체를 지연하는 알고리즘을 적용한 새로운 버퍼교체 정책(LRU-Dirty Page Later-Cold Detection, 이하 LRU-DPL-CD)을 제시하고 성능을 분석한다. 트레이스 기반 시뮬레이션 실험에서 LRU-DPL-CD는 버퍼 적중률의 큰 감소 없이 쓰기 작업과 지우기 작업의 횟수를 감소시켰으며, 그 결과 전체 플래시 메모리의 I/O 수행속도가 증가하는 결과를 보였다.

• 한국초등수학교육학회지
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• 제19권4호
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• pp.563-588
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• 2015

초등학교에서는 여러 가지 이유로 교수학적 변환이 불가피하다. 수학에서는 덧셈과 곱셈은 이항연산, 뺄셈과 나눗셈은 단항연산으로 다루고 있는 반면, 초등에서는 사칙연산 모두를 이항연산으로 취급하는 교수학적 변환을 시도한다. 그런데 사칙연산의 개념을 '익힌다는 것'은 개념이 어떻게 도입되는가가 더 중요하게 부각된다는 점에서 개념을 이해하는 것과는 다르다. 이에 본 연구에서는 자연수와 분수의 사칙연산을 개념 익히기(개념이 어떻게 도입되고 있는지와 연산 선택의 문제)와 연산 사이의 연결이라는 두 가지 관점으로 분석하여, 자연수와 분수의 사칙연산 지도와 관련된 몇 가지 시사점을 도출하였다. 분수의 나눗셈에서는 상황을 바탕으로 연산을 선택하지 않고 곧장 분수의 곱셈과의 연결을 시도했다는 것과 분수의 나눗셈을 그 자체로 이해하기 위해서는 5학년 2학기와 6학년 1학기에 걸쳐 제시되어 있는 분수의 나눗셈을 통합해야 한다는 것 등이 그것들이다. 이는 후속 교과서 개발 시 유용한 참고자료가 될 것으로 판단된다.

• 성인간호학회지
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• 제14권3호
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• pp.428-437
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• 2002

Purpose: The purpose of this study is to examine the changes of surgical patients' body temperature in applying warming to patients. The study of an effective nursing intervention, which aims to prevent hypothermia during surgical operations, use of anesthesia, and to remove dermal discomforts. The nonequivalent control group pre-test/post-test design was used for this quasi-experimental study. Method: The study subjects were adult patients who would take a surgical operation under general anesthesia in C Hospital; the surgical operations done were, total abdominal hysterectomy or Myomectomy; 20 patients were included in experimental group I, 20 patients were included in experimental group II, and 20 patients were in the comparative group. The total number of study subjects was 60. The data was collected from September the 1st, 2001 to October the 20th, 2001. The data was analyzed by SPSS program, F-test and Repeated measures of ANOVA. Multi-comparison method of DUNCAN was used for the sections that show the significant differences at the level of p<.05, which was a posterior examination. Result: 1) "The body temperatures of the three groups of patients will be respectively different at the end of the operations; experimental group I to which warming was applied before the operations, experimental group II to which warming was applied during the operations, and the comparative group with no warming being given," showed (F=12.609, p=.000). 2) "Degrees of shivering symptoms for the three groups will be respectively different at the end of the operations; experimental group I which applied warming before operations, experimental group II which applied warming during operations and the comparative group with no warming." Showed assumed (F=6.626, p=.000). Conclusion: Summing up the above study, the warming assumed during operations was a more effective nursing intervention for preventing patients' hypothermia than the warming assumed before operations.

• 한국초등수학교육학회지
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• 제21권3호
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• pp.531-546
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• 2017

본 연구에서는 계산 순서를 지도하는데 유용한 교수법적 내용 지식을 제공하기 위해 사칙계산 사이의 우선권은 어떠한 근거로 결정되었는지 살펴보고, 계산 순서를 바라보는 입장에 관해 논의하였다. 이러한 논의 결과를 바탕으로 다음 다섯 가지 제언을 결론으로 제시한다. 첫째, 교사들에게 덧셈과 뺄셈의 혼합계산 및 곱셈과 나눗셈의 혼합계산의 경우, 각각 뺄셈과 나눗셈부터 계산해도 동일한 계산 결과를 구할 수 있다는 것을 확인하는 기회를 제공할 필요가 있다. 둘째, 교사들에게 식의 왼쪽부터 차례대로 계산하는 규칙이 관습으로 자리 잡은 이유에 관해 논의할 수 있는 기회를 제공할 필요가 있다. 셋째, 교사들에게 덧셈과 곱셈의 혼합계산에서 곱셈이 덧셈보다 우선한다는 규칙 설정의 동인을 설명해 보는 기회를 제공할 필요가 있다. 넷째, 교사들에게 괄호가 있는 식에서 하나의 수량이라는 괄호의 의미를 강조할 필요가 있다. 다섯째, 교사용 지도서에서 계산 순서의 입장을 기술할 때는 계산 순서의 관습적, 개념적 입장을 모두 기술하여 교사들의 계산 순서에 대한 이해를 심화시킬 필요가 있다.

• 한국경영과학회지
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• 제40권2호
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• pp.63-77
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• 2015

The territorial air that our sovereignty is being applied to is divided into several zones and areas. In order to use and manage them effectively, these zones and areas have laws, regulations and rules. The number of airspaces (MOA : Military Operation Area) and Ranges that are used in the military are limited and many airbases are being used for training. Currently the central department manages some, and the rest are independent airbases. Therefore, efficient allocation is not performed and the result occurs where airspaces and ranges are allocated unnecessarily. This is increasing the workload of staff leading to unnecessary re-work. To slove problem, this study proposed models for allocating airspaces and ranges using goal programming with multi-objective functions of minimizing the deviations of the target values.

• 시스템엔지니어링학술지
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• 제11권1호
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• pp.73-79
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• 2015

This paper describes boundary analysis for modeling Aircraft Carrier Sortie Generation System(CVSGS). An aircraft carrier, as a super system, is a warship going into battle by operating a number of aircraft on deck and it should be lay down a definition about aviation operations interacting between aircraft carrier and carrier air wing in small deck area. For this reason this paper models common aviation support system for generating sortie basic unit of carrier aviation operations unlike to general warship and defines boundaries between this system and aircraft carrier and carrier air wing. This paper analysis activities of aircraft carrier and embarked carrier air wing in carrier aviation operations, and analysis and defines boundaries Aircraft Carrier Sortie Generation System(CVSGS) to perform core functions in interacting between aircraft carrier and embarked carrier air wing.

• Journal of Trauma and Injury
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• 제35권3호
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• pp.195-201
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• 2022

Purpose: The objective of this study was to determine the effects of coronavirus disease 2019 (COVID-19) on the volume of trauma patients, the number of orthopedic trauma operations, and the severity of injuries. We also investigated the correlations between social distancing and these variables. Methods: This was a retrospective review of trauma patient cases at a single focused training center for trauma in Korea from January 2017 to April 2021. The COVID-19 group included patients treated from January 1 to April 30 in 2020 and 2021, and the control group included patients treated during the same months from 2017 to 2019. The volume of trauma patients according to the level of social distancing was evaluated among patients treated from August 2, 2020 to November 23, 2020. Results: The study included 3,032 patients who presented to the emergency department with traumatic injuries from January to April 2017 to 2021. The average number of patients was 646.7 and 546.0 in the control and COVID-19 groups, respectively. The percentage of patients injured in traffic accidents (TAs) decreased from 25.0% to 18.2% (P<0.0001). The proportions of in-car TAs and pedestrian TAs also decreased from 6.7% and 10.8% to 3.5% and 6.0%, respectively (P=0.0002 and P<0.0001). The percentage of bicycle TAs increased from 2.4% to 4.0% (P=0.0128). The proportion of patients with an Injury Severity Score above 15 and the mortality rate did not change significantly. As the level of social distancing increased, the number of trauma patients and the number of trauma injuries from TAs decreased. The number of orthopedic trauma operations also depended on the social distancing level. Conclusions: The number of trauma patients presenting to the emergency department decreased during the COVID-19 period. The volume of trauma patients and orthopedic trauma operations decreased as the social distance level increased.

• 산업공학
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• 제20권2호
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• pp.204-215
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• 2007

This paper addresses vehicle routing planning in freight container transportation systems where a number of loaded containers are to be delivered to their destination places. The system under consideration is static in that all transportation requirements are predetermined at the beginning of a planning horizon. A two-phased procedure is presented for freight container transportation. In the first phase, the optimal model is presented to determine optimal total time to perform given transportation requirements and the minimum of number of vehicles required. Based on the results from the optimal model, in the second phase, ASA(Accelerated Simulated Annealing) algorithm is presented to perform all transportation requirements with the least number of vehicles by improving initial vehicle routing planning constructed by greedy method. It is found that ASA algorithm has an excellent global searching ability through various experiments in comparison with existing methods.

• 한국경영과학회지
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• 제31권2호
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• pp.27-39
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• 2006

The Collaborative Filtering (CF) is one of the popular techniques for personalization in e-commerce storefronts. For CF-based recommendation, every customer needs to provide subjective evaluation ratings for some products based on his/her preference. Also, if an e-commerce site recommends a new product, some customers should rate it. However, there is no in-depth investigation on the impacts on recommendation performance of two number of ratings, i.e. the number of ratings of an individual customer and the number of ratings of an item, even though these are important factors to determine performance of CF methods. In this study, using publicly available EachMovie data set, we empirically investigate the relationships between the two number of ratings and the performance of CF. For the purpose, three analyses were executed. The first and second analyses were performed to investigate the relationship between the number of ratings of a particular customer and the recommendation performance of CF. In the third analysis, we investigate the relationship between the number of ratings on a particular item and the recommendation performance of CF. From these experiments, we can find that there are thresholds in terms of the number of ratings below which the recommendation performances increase monotonically. That is, the number of ratings of a customer and the number of ratings on an item are critical to the recommendation performance of CF when the number of ratings is less than the thresholds, but the value of the ratings decreases after the numbers of ratings pass the thresholds. The results of the experiments provide insight to making operational decisions concerning collaborative filtering in practice.

• 전자공학회논문지CI
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• 제41권5호
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• pp.17-23
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• 2004

본 논문은 십진 나눗셈에서 연산 속도를 향상시키기 위해 혼합 나눗셈 알고리즘을 제안한다. 이진수 체계에서는 비복원 알고리즘이 복원 알고리즘에 비해 항상 작은 횟수를 갖지만 십진 연산에서는 몫의 값에 따라 연산 횟수가 달라진다. 십진수는 한 자리로 나타낼 수 있는 수의 범위가 0～9 이므로 현재 부분 나머지의 절대 값과 이전 부분 나머지의 절대 값을 비교하여 이전 부분 나머지의 절대 값이 현재 부분 나머지의 절대 값 보다 크면 비복원 알고리즘을 선택하고 작으면 복원 알고리즘을 선택함으로써 연산 횟수를 줄일 수 있다. 몫이 64 자리일 경우 제안한 흔합 알고리즘은 복원 알고리즘에 비해 80.9%의 연산 횟수를 줄였고 비복원 알고리즘에 비해 64.5%의 연산 횟수를 줄였다.