• Steel and Composite Structures
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• 제49권5호
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• pp.503-516
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• 2023

In the current examination, a trigonometric shear deformation theory is hired to govern natural frequencies of a functionally graded porous microplate which is covered by two nanocomposite layers. The properties of the structure are varied based on the specified patterns. Utilizing the modified form of couple stress theory for taking the scale effect into account in conjunction with Hamilton's principle, the motion equations are obtained. Then, they are solved via Fourier series functions as an analytical approach. After confirming the results' accuracy, various parameters' effect on the results is investigated. Designing and manufacturing more efficient structures, especially those that are subjected to multi-physical loads can be accounted as findings of this work.

• Geomechanics and Engineering
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• 제37권3호
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• pp.243-251
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• 2024

In the current work, a poro-thermoelastic half-space issue with temperature-dependent characteristics and an inclined load is examined in the framework of the three-phase-lag model (3PHL) while taking into account the effects of magnetic and gravity fields. The resulting coupled governing equations are non-dimensional and are solved by normal mode analysis. To investigate the impacts of the gravitational field, magnetic field, inclined load, and an empirical material constant, numerical findings are graphically displayed. MATLAB software is used for numerical calculations. Graphs are used to visualize and analyze the computational findings. It is found that the physical quantities are affected by the magnetic field, gravity field, the nonlocal parameter, the inclined load, and the empirical material constant.

• International Journal of Internet, Broadcasting and Communication
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• 제16권3호
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• pp.16-26
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• 2024

Mobile edge computing (MEC) plays a crucial role in improving the performance of resource-constrained mobile devices by offloading computation-intensive tasks to nearby edge servers. However, existing methods often neglect the critical consideration of future task requirements when making offloading decisions. In this paper, we propose an innovative approach that addresses this limitation. Our method leverages recurrent neural networks (RNNs) to predict task sizes for future time slots. Incorporating this predictive capability enables more informed offloading decisions that account for upcoming computational demands. We employ genetic algorithms (GAs) to fine-tune fitness functions for current and future time slots to optimize offloading decisions. Our objective is twofold: minimizing total processing time and reducing energy consumption. By considering future task requirements, our approach achieves more efficient resource utilization. We validate our method using a real-world dataset from Google-cluster. Experimental results demonstrate that our proposed approach outperforms baseline methods, highlighting its effectiveness in MEC systems.

• 한국지반환경공학회 논문집
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• 제11권10호
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• pp.41-48
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• 2010

본 연구에서는 기존에 적용된 준설투기장 설계에서 준설투기장에서 배출되는 상등수의 부유물 농도 예측에 대한 적합성 평가를 위하여 실제 현장 준설 시 준설투기장 내에서 준설토의 입도분포 및 상등수의 부유물 농도 분포를 측정하여 설계 예측 값과 비교하였으며, 상등수의 유속과 부유물 농도와의 관계를 분석하였다. 평가 결과, 현장 측정값과 설계 예측값이 비교적 유사한 경향을 보였으나, 준설 초기 및 상등수 유속이 증가한 시점에서는 설계 예측값과 상이한 측정값을 보였다. 이는 기존에 적용된 준설투기장 설계법이 준설 기간에 따라 민감하게 변화하는 준설토의 침강 깊이 및 상등수의 유속 등을 반영하지 못하기 때문으로 판단된다. 또한 준설투기장에서 동시에 측정된 유속과 부유물 농도의 분포가 유사한 경향을 보이므로 상등수의 유속과 부유물 침전이 상당히 밀접한 관계가 있는 것으로 관측되었다. 따라서, 현장 준설투기장 상황 변화를 보다 정확히 예측하기 위하여 준설토 계면고, 침강깊이, 상등수 유속에 따라 변화하는 부유물 침전을 고려한 준설투기장 설계법이 필요하다고 사료된다.

• Computers and Concrete
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• 제8권2호
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• pp.125-142
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• 2011

In the present paper, a numerical simulation method based on mesoscopic composite structure of concrete, the truss network model, is developed to evaluate the diffusivity of concrete in order to account for the microstructure of concrete, the binding effect of chloride ions and the chloride concentration dependence. In the model, concrete is described as a three-phase composite, consisting of mortar, coarse aggregates and the interfacial transition zones (ITZs) between them. The advantage of the current model is that it can easily represent the movement of mass (e.g. water or chloride ions) through ITZs or the potential cracks within concrete. An analytical method to estimate the chloride diffusivity of mortar and ITZ, which are both treated as homogenious materials in the model, is introduced in terms of water-to-cement ratio (w/c) and sand volume fraction. Using the newly developed approaches, the effect of cracking of concrete on chloride diffusion is reflected by means of the similar process as that in the test. The results of calculation give close match with experimental observations. Furthermore, with consideration of the binding capacity of chloride ions to cement paste and the concentration dependence for diffusivity, the one-dimensional nonlinear diffusion equation is established, as well as its finite difference form in terms of the truss network model. A series of numerical analysises performed on the model find that the chloride diffusion is substantially influenced by the binding capacity and concentration dependence, which is same as that revealed in some experimental investigations. This indicates the necessity to take into account the binding capacity and chloride concentration dependence in the durability analysis and service life prediction of concrete structures.

• 대한인간공학회지
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• 제36권5호
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• pp.467-484
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• 2017

Objective: The purpose of this paper is to review, with the main focus on aviation safety technology and management program, how human factors are currently taken into consideration within transportation sectors, especially aviation, and to further share related information. Background: Human factors account for the majority of aviation accidents/incidents. Thus, the aviation sector has been comparatively quick in developing and applying technologies and management programs that deal with human factors. This paper reviews the latest safety technologies and management programs regarding human factors and aims to identify the trend. Method: This paper, based on literature research and practical experience, examines the latest international standards on technologies and management programs, those that deal with human factors and are adopted by international and domestic aviation organization. The main focus of discussion is how human factors are reflected during the system design and operation process. Results: The current most important issue in designing is the consideration of human factors in Cockpit, Automation, and Safety system technology design. From an operational point of view, the issues at hand are screening and training aviation workers to promote aviation safety, providing education on human factors and CRM/TEM, and running a safety management program to implement SMS. They were discussed based on the operational experience within the aviation sector. Conclusion: Major examples of a human factors approach to promote aviation safety are safety programs and various safety and monitoring technologies applied to aviation personnel for error management. These programs must be managed in an integrated manner that takes both the system designing and operational point of view into account. Application: It is thought that the human factors approach for promoting aviation safety reviewed in this paper can be extended and applied to safety management programs in other transportation sectors such as the railroad, maritime, road traffic etc.

• Journal of Information Technology Applications and Management
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• 제27권3호
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• pp.55-68
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• 2020

Recently, organizational workers are complaining of stress due to excessive connection on SNS and are claiming the right to disconnect. If these claims are not properly managed, organizational performance may deteriorate. Therefore, organizations need to approach the issue of the right to disconnect carefully. This study examined the effects of work connection at office, IT hyper-connected environments, and work connection at home on the right to disconnect, and analyzed the effect of this perception on job satisfaction, and then analyzed gender differences in these effects. The research results are as follows. First, it was found that the work connection at office lowered the right to disconnect. Second, the deeper IT hyper-connected environment, the higher the right to disconnect. Third, it was found that the work connection at home raises the right to disconnect. Fourth, it was found that the right to disconnect increases job satisfaction to a certain extent, but lowers job satisfaction when it exceeds the appropriate line. Fifth, in the case of men, the effect of the right to disconnect on job satisfaction has sharply increased and sharply reduced. On the other hand, in women, it gradually increased and then decreased slowly. Considering the results of these studies, organizations need to check the current status and appropriate level of the work connection at home for organizational performance management. Organizations need to formulate organizational management measures that take into account the positive and negative functions of the right to disconnect. And organizations need to come up with management measures that take gender into account.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2005년도 추계학술대회
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• pp.569-579
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• 2005

International capital movement has made progress at global liberalization of finance and foreign exchange, international monetary norm changing into floating exchange rate system, easiness of collection of information and trade at improvement of information communication technology from early of 1970's. Results of empirical test for relation between foreign exchange rate or various determination factors of foreign exchange rate and interest rate are followed by next sentences. First, according to relation between foreign exchange rate and interest rate, correlation for each of variables after OECD entrance is increased. 'But, long-term & short-term interest rate is affected by Hanbo & Kia's bankruptcy, continuous large scale coporates bankruptcy and crisis of foreign exchange. Therefore, financial instability is occured. If portfolio investment fund has been inflow as it is mollified by continuous shortage of foreign exchange and fall of country's credit rating, it is expected to have positive effect for long-term & short-term interest rate from appreciation of won against dollar. Second, results from relation between determination factor of foreign exchange rate and interest rate are followed by next sentences. If surplus of current account and goods account is continued, yield of corporate bond is to be stable. But, margin of surplus is expected to diminish after second quarter 98, and difference between external and domestic interest (after adjusting foreign exchange rate) is to be diminished. And if net inflows of foreign investor's fund (stock and bond) is diminished, it is to have negative effect for yield of corporate bond. According to foreign investor's investment movement of previous years, hedge fund were stayed at least during two years in Mexico. It means that sudden capital outflow is not to be happened at Korea.

• 한국식생활문화학회지
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• 제6권4호
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• pp.403-411
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• 1991

A survey was made, from May to June 1991, to reveal the current situation of the meal management of the homemakers in Jeonbuk area. The results obtained from 464 homemakers were summerized as follows. The meal expenses were planned and managed mostly by the homemakers (93.3%). The 31.1% homemakers expended 200,000-300,000 Won a month for meals and the average expenditure was 294,106 Won. Among the homemakers who responded, the 34.0% managed their account books for meal expenses. With decreasing age(p<0.05), increasing education level (p<0.001), and increasing the income(p<0.01), the number of those who managed the account book tended to be higher. Usually they bought their foods at the market place (52.1%) and they did every other days(33.2%). The 46.9% planned what to buy and chose the best ones among the foods they planned to buy at the market. The percentage of those who prepared their menus planned in advance was only 5.5%. The most homemakers cooked for themselves (96.8%). On cooking and buying foods, the 48.2% considered their husbands first and the 64.4% regarded the tastes and needs of their families as the most important thing. The majority (66.2%) regarded the dinner as the most important among those three times of meals. The 39.6% prepared Kimchi twice a month. The foods they prepared for each meal were usually 4-5 kinds (43.2%). Mostly they prepared meals three times a day (49.1%). The average times spent in preparing and cleaning the tables for lunch and breakfast were 41.6, 96.2 minutes respectively. The homemakers who had jobs tended to spend less time in preparing and clearing the tables than those who had not (p<0.01, p<0.001). The 58.0% had complaints in that the food prices were too high and their moneys for meal preparation were insufficient and the 16.6% had difficulty in satisfying the tastes of their families.

• Asian Pacific Journal of Cancer Prevention
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• 제14권3호
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• pp.1905-1909
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• 2013

Objective: The aim of the current study was to evaluate changes in treatment outcomes in terms of health-related quality of life (HRQoL) and symptom burden at zero, one, three, and six months after an initial diagnosis of colorectal cancer. The demographic and clinical characteristics that account for outcome changes in patients were investigated using a repeated measures framework. Methods and Materials: A cohort study was performed of 134 colorectal cancer patients followed from diagnosis to 6 months post-treatment in Central Taiwan. HRQoL and symptoms were assessed at diagnosis and one, three, and six months thereafter. The Functional Assessment of Cancer Therapy-Colon (FACT-C) questionnaire, VAS pain, and the Memorial Symptom Assessment Scale (MSAS) were used for data collection. A generalized estimating equation (GEE) was applied for statistical analysis. Results: The majority of the patients were male (55%) and married (91.5%). The mean age was 60.4 years (SD = 11.71). Most were diagnosed stage III and IV colorectal cancer (54.5%). All underwent surgery; some also received chemotherapy (CT) or concurrent chemoradiation therapy (CCRT). The results of the GEE showed that overall, the HRQoL, pain, and symptoms of the patients significantly improved over the treatment period. Patients with stage IV disease who had received surgery and CCRT showed the worst HRQoL. Females, patients with comorbidity, and stage IV patients had higher pain scores over time. Female and stage IV patients had more severe physical symptoms, whereas stage II and IV patients had worse psychological symptoms over time. Conclusion: The patients' HRQoL, pain, and symptoms significantly improved over the 6-month treatment period. Certain patient and clinical variables accounted for changes in treatment outcomes regarding HRQoL and symptom burden in colorectal cancer patients.