• 제목/요약/키워드: repeated impact

검색결과 253건 처리시간 0.03초

유전자 알고리즘을 이용한 프로젝트 포트폴리오 투입인력 최적화 모델에 관한 연구 (A Study on the Optimization Model for the Project Portfolio Manpower Assignment Using Genetic Algorithm)

  • 김동욱;이원영
    • 한국IT서비스학회지
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    • 제17권4호
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    • pp.101-117
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    • 2018
  • Companies are responding appropriately to the rapidly changing business environment and striving to lead those changes. As part of that, we are meeting our strategic goals through IT projects, which increase the number of simultaneous projects and the importance of project portfolio management for successful project execution. It also strives for efficient deployment of human resources that have the greatest impact on project portfolio management. In the early stages of project portfolio management, it is very important to establish a reasonable manpower plan and allocate performance personnel. This problem is a problem that can not be solved by linear programming because it is calculated through the standard deviation of the input ratio of professional manpower considering the uniformity of load allocated to the input development manpower and the importance of each project. In this study, genetic algorithm, one of the heuristic methods, was applied to solve this problem. As the objective function, we used the proper input ratio of projects, the input rate of specialist manpower for important projects, and the equal load of workload by manpower. Constraints were not able to input duplicate manpower, Was used as a condition. We also developed a program for efficient application of genetic algorithms and confirmed the execution results. In addition, the parameters of the genetic algorithm were variously changed and repeated test results were selected through the independent sample t test to select optimal parameters, and the improvement effect of about 31.2% was confirmed.

상추재배를 위한 시설하우스 배액의 비효평가 - 무기태 질소를 중심으로 - (Analysis of the Fertilizing Effects of Hydroponic Waste Solution on Lettuce (Lactuca sativa var. captitata) Cultivation - Based on Inorganic Nitrogen Content -)

  • 윤성욱;임주미;문종필;장재경;박민정;손진관;이현호;서효민;최덕규
    • 한국농공학회논문집
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    • 제63권4호
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    • pp.13-21
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    • 2021
  • The feasibility of HWS for agricultural use was analyzed through a crop cultivation test to utilize the hydroponic waste solution (HWS) generated from the nutriculture greenhouse. The fertilizing effect of HWS was assessed on the basis of the inorganic nitrogen (N) mostly existed in HWSs, and nitrogen (urea) fertilizer. Lettuce was selected as the target crop influenced by the soil treatment and also for the crop cultivation test. Thus, the change in growth characteristics of lettuce and that in chemical characteristics of the soil were investigated. In terms of the growth of lettuce, the C control group with 70% nitrogen (urea) fertilizer and 30% HWS and the D control group with 50% nitrogen (urea) fertilizer and 50% HWS were more effective than the practice control group (B) with 100% nitrogen (urea) fertilizer. The results of this study confirmed the combined applicability of the chemical fertilizer and HWS for crop cultivation. Because NO3-N present in HWS has a high possibility of leaching into the soil, its applicability as a fertilizer has been considered to be relatively low in Korea. However, if an appropriate mixing ratio of urea fertilizer and HWS could be applied, the problems associated with leaching of nitrate nitrogen could be reduced with beneficial effects on crop cultivation. Thus, future studies are required on the treatment effect of HWS with repeated cultivation, impact assessment on the surrounding environment, and appropriate fertilization methods using nitrogen (urea) fertilizer and HWS. These studies would facilitate the sustainable recycling of HWS.

문제음주 대학생을 위한 자기결정성증진 절주프로그램 개발 및 효과 (Effectiveness of Drinking Reduction Program Focused on Self-Determination Enhancement for College Students with Problematic Drinking)

  • 마진경;유문숙
    • 대한간호학회지
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    • 제51권3호
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    • pp.265-279
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    • 2021
  • Purpose: This study examined the impact of a drinking reduction program on drinking motivation, drinking refusal self-efficacy, and problematic drinking behaviors in college students with problematic drinking habits. Methods: This study incorporated a non-equivalent control group prepost-test design. Study participants included 58 college students who scored 12 or more in the AUDIT-K test (Alcohol Use Disorders Identification Test-Korean version) (experimental group: 30; control group: 28). The intervention consisted of eight sessions and was conducted once a week. It was designed to promote autonomy, competence, and relatedness-the three elements of basic psychological needs in self-determination theory. The participants were assessed before the intervention, immediately after, and four weeks post intervention. Data were collected from October 12 to December 31, 2017. The analysis employed the chi-square test, Fisher's exact test, independent t-test, and repeated measures ANOVA using SPSS/WIN 22.0. Results: The mean age of participants was 21.8 years. There were 30 men (51.7%) and 28 women (48.3%). The differences in drinking motivation, drinking refusal self-efficacy, and problematic drinking behaviors were statistically significant for the group by time interaction (F = 42.56, p < .001; F = 54.96, p < .001; F = 39.90, p < .001, respectively). Conclusion: The findings indicate that the intervention effectively decreases drinking motivation, increases drinking refusal self-efficacy, and decreases problematic drinking behaviors. It can be an efficient strategy for college students with problematic drinking habits to enhance their self-determination ability.

무폭약 시험 장치 개발을 위한 수중폭발 특성에 대한 연구 (A Study on the Characteristics of Underwater Explosion for the Development of a Non-Explosive Test System)

  • 이한솔;박규동;나양섭;이승규;박경훈;정현
    • 대한조선학회논문집
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    • 제57권6호
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    • pp.322-330
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    • 2020
  • This study deals with underwater explosion (UNDEX) characteristics of various non-explosive underwater shock sources for the development of non-explosive underwater shock testing devices. UNDEX can neutralize ships' structure and the equipment onboard causing serious damage to combat and survivability. The shock proof performance of naval ships has been for a long time studied through simulations, but full-scale Live Fire Test and Evaluation (LFT&E) using real explosives have been limited due to the high risk and cost. For this reason, many researches have been tried to develop full scale ship shock tests without using actual explosives. In this study, experiments were conducted to find the characteristics of the underwater shock waves from actual explosive and non-explosive shock sources such as the airbag inflators and Vaporizing Foil Actuator (VFA). In order to derive the empirical equation for the maximum pressure value of the underwater shock wave generated by the non-explosive impact source, repeated experiments were conducted according to the number and distance. In addition, a Shock Response Spectrum (SRS) technique, which is a frequency-based function, was used to compare the response of floating bodies generated by underwater shock waves from each explosion source. In order to compare the magnitude of the underwater shock waves generated by each explosion source, Keel Shock Factor (KSF), which is a measure for estimating the amount of shock experienced by a naval ship from an underwater explosionan, was used.

유한 및 무한 용량 대기열을 가지는 선점 우선순위 M/G/1 대기행렬 (M/G/1 Preemptive Priority Queues With Finite and Infinite Buffers)

  • 김길환
    • 산업경영시스템학회지
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    • 제43권4호
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    • pp.1-14
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    • 2020
  • Recently, M/G/1 priority queues with a finite buffer for high-priority customers and an infinite buffer for low-priority customers have applied to the analysis of communication systems with two heterogeneous traffics : delay-sensitive traffic and loss-sensitive traffic. However, these studies are limited to M/G/1 priority queues with finite and infinite buffers under a work-conserving priority discipline such as the nonpreemptive or preemptive resume priority discipline. In many situations, if a service is preempted, then the preempted service should be completely repeated when the server is available for it. This study extends the previous studies to M/G/1 priority queues with finite and infinite buffers under the preemptive repeat-different and preemptive repeat-identical priority disciplines. We derive the loss probability of high-priority customers and the waiting time distributions of high- and low-priority customers. In order to do this, we utilize the delay cycle analysis of finite-buffer M/G/1/K queues, which has been recently developed for the analysis of M/G/1 priority queues with finite and infinite buffers, and combine it with the analysis of the service time structure of a low-priority customer for the preemptive-repeat and preemptive-identical priority disciplines. We also present numerical examples to explore the impact of the size of the finite buffer and the arrival rates and service distributions of both classes on the system performance for various preemptive priority disciplines.

Yield strength estimation of X65 and X70 steel pipe with relatively low t/D ratio

  • Kim, Jungho;Kang, Soo-Chang;Kim, Jin-Kook;Song, Junho
    • Steel and Composite Structures
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    • 제38권2호
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    • pp.151-164
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    • 2021
  • During the pipe forming process, a steel plate undergoes inelastic behavior multiple times under a load condition repeating tension and compression in the circumferential direction. It derives local reduction or increase of yield strength within the thickness of steel pipes by the plastic hardening and Bauschinger effect. In this study, a combined hardening model is proposed to effectively predict variations of yield strength in the circumferential direction of API-X65 and X70 steel pipes with relatively low t/D ratio during the forming process, which is expected to experience accumulated plastic strain of 2~3%, the typical Lüder band range in a low-carbon steel. Cyclic tensile tests of API-X65 and X70 steels were performed, and the parameters of the proposed model for the steels were calibrated using the test results. Bending-flattening tests to simulate repeated tension and compression during pipe forming were followed for API-X65 and X70 steels, and the results were compared with those by the proposed model and Zou et al. (2016), in order to verify the process of material model calibration based on tension-compression cyclic test, and the accuracy of the proposed model. Finally, parametric analysis for the yield strength of the steel plate in the circumferential direction of UOE pipe was conducted to investigate the effects of t/D and expansion ratios after O-forming on the yield strength. The results confirmed that the model by Zou et al. (2016) underestimated the yield strength of steel pipe with relatively low t/D ratio, and the parametric analysis showed that the t/D and expansion ratio have a significant impact on the strength of steel pipe.

스쿼트 운동, 브레이싱 운동, 그리고 유산소 운동이 폐기능에 미치는 영향 비교 (Comparison of the Effects of Squat Exercise, Bracing Exercise, and Aerobic Exercise on Lung Function)

  • 김현수;김충유;이건철
    • 대한통합의학회지
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    • 제10권2호
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    • pp.169-176
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    • 2022
  • Purpose : The purpose of this study is to investigate the effect of squat, bracing and aerobic exercise on lung function, which is known to be effective for strength training, on lung function. Methods : The study was conducted with 33 students from Busan K university. Eleven students were assigned to squats, bracing, and aerobic exercise, six weeks three times a week. In order to measure lung activity, pony Fx manufactured the change amount of FVC (forced vital capacity), FEV1 (Forced expiratory volume at one second), and FEV1/FVC % (forced vital capacity/forced expiratory volume at one second) was analyzed after inputting the information of experimental group A and B controls. As a method of measurement, the difference between the three groups was analyzed using repeated ANOVA. Results : As a result of analyzing the effects of squat, bracing, and aerobic exercise for 6 weeks, all values of FVC, FEV1, FEV1/FVC % were increased from 0 weeks to 6 weeks except FEV1/FVC %. There was no significant difference in FVC from week 3 to week 6. In the squat, bracing, and aerobic exercise, the changes in spirometry showed that the FVC, FEV1, and FEV1/FVC % values in bracing exercise were significantly increased with time than before exercise. As a result of analyzing the changes in the spirometry of squat, bracing, and aerobic exercise, the FVC, FEV1, FEV1/FVC % values in the squat exercise showed statistically significant difference according to the period, but the lowest increase among the three groups. Conclusion : In conclusion, aerobic, bracing and squat exercises all had a significant impact on improving lung function. Therefore, even without aerobic exercise, squat or bracing exercise alone can be expected to improve lung function.

IT-based physical activity and exercise programs for individuals with spinal cord injury

  • Choi, Hyunhee
    • 한국컴퓨터정보학회논문지
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    • 제27권2호
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    • pp.187-194
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    • 2022
  • 척수장애인들에게 있어 신체활동 및 운동을 장려함으로써 건강 결과에 긍정적인 영향을 미칠 수 있도록 하는 것이 중요하다. 현재 증거에 따르면 IT기반으로 하는 근력 및 근지구력, 심폐 운동, 전기 자극 운동과 로봇 운동 등 모두 체력 구성 요소를 개선하고 2차 건강 합병증의 위험을 줄이며 만성 신체 장애가 있는 사람들의 전반적인 건강에 긍정적인 영향을 미칠 수 있다. 근력 및 근지구력을 증진하기 위해서는 운동 빈도는 주 2회, 3세트 실시하도록 하며 근력의 증진을 위해서는 < 5 Reps으로, 일반적인 강도는 6~15회 반복하도록 하며, 근지구력을 향상시키기 위해서는 15~30회 반복하도록 한다. 심폐 능력의 향상을 위해서는 주 3-5회, 20~60분, 최고심박수의 50~80%로 실시하도록 하였다. 따라서 IT 기반의 다양한 운동 이점을 실현하고 전문 장비, 시설 및 트레이너에 대한 접근을 위한 더 높은 자원 투자가 필요하다.

The Impact of Fractional Flow Reserve on Clinical Outcomes after Coronary Artery Bypass Grafting: A Meta-analysis

  • Yoonjin, Kang;Heeju, Hong;Suk Ho, Sohn;Myoung-jin, Jang;Ho Young, Hwang
    • Journal of Chest Surgery
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    • 제55권6호
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    • pp.442-451
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    • 2022
  • Background: This meta-analysis was conducted to evaluate the effect of fractional flow reserve (FFR) on clinical outcomes after coronary artery bypass grafting (CABG). Methods: Five online databases were searched for studies that (1) enrolled patients who underwent isolated CABG or CABG with aortic valve replacement and (2) demonstrated the effect of an FFR-guided strategy on major adverse cardiac events (MACE) after surgery based on a randomized controlled trial or adjusted analysis. MACE included cardiac death, acute myocardial infarction (MI), and repeated revascularization. The primary outcomes were all MACE outcomes and a composite of all-cause death and MI, and the secondary outcomes were the individual MACE outcomes. Publication bias was assessed using a funnel plot and the Egger test. Results: Six articles (3 randomized and 3 non-randomized studies: n=1,027) were selected. MACE data were extracted from 4 studies. The pooled analyses showed that the risk of MACE was not significantly different between patients who underwent FFR-guided CABG and those who underwent angiography-guided CABG (hazard ratio [HR], 0.80; 95% CI, 0.57-1.12). However, the risk of the composite of death or MI was significantly lower in patients undergoing FFR-guided CABG (HR, 0.62; 95% CI, 0.41-0.94). The individual MACE outcomes were not significantly different between FFR-guided and angiography-guided CABG. Conclusion: FFR-guided CABG might be beneficial in terms of the composite outcome of death or MI compared with angiography-guided CABG although data are limited.

치매 환자의 행동심리 증상완화를 위한 가상현실 프로그램의 효과 (Effect of Virtual Reality Program for Alleviating Behavioral and Psychological Symptoms of Dementia Patients)

  • 박선민;최승이;김정희
    • 대한간호학회지
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    • 제52권2호
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    • pp.121-133
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    • 2022
  • Purpose: This study examined the impact of a virtual reality intervention program based on psychological needs on behavioral and psychological symptoms, apathy, and quality of life (QOL) in patients with dementia or mild cognitive impairment living in nursing facilities. Methods: This study is nonequivalent control group pretest-posttest design of quasi-experimental study. The study collected data from November 18, 2020 to July 24, 2021 from patients with dementia or mild cognitive impairment (30 in the experimental group and 30 in the control group) at three nursing facilities in G city using self-reporting and caregiver-informant reporting methods. The analysis employed the chi-square test, Fisher's exact test, paired t-test, independent t-test, Wilcoxon signed rank test, Mann-Whitney U, repeated measures ANOVA, GEE, using SPSS/WIN 27.0. Results: The severity of behavioral and psychological symptoms (Wald 𝛘2 = 2.68, p = .102) and the care burden of caregivers (Wald 𝛘2 = 1.72, p = .190) were not significant and was no significant time and group interaction effect (Wald 𝛘2 = 0.63, p = .426, Wald 𝛘2 = 0.52, p =. 471). The difference in apathy and QOL score were statistically significant for the group-time interaction (F = 43.65, p < .001; F = 4.35, p = .041). Conclusion: The virtual reality intervention program of this study shows a positive effect on the apathy reduction and QOL of patients with dementia or mild cognitive impairment residing in nursing facilities.