• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5701-5722
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• 2018

The continuous increase in the cost of energy production and concerns for environmental sustainability are leading research communities, governments and industries to amass efforts to reduce energy consumption and global $CO_2$ footprint. Players in the information and communication industry are keen on reducing the operational expenditures (OpEx) and maintaining the profitability of cellular networks. Meanwhile, network virtualization has been proposed in this regard as the main enabler for 5G mobile cellular networks. In this paper, we propose a generic framework of slice resource provisioning and customized physical resource allocation for energy-efficiency and quality of service optimization. In resource slicing, we consider user demand and population resources provisioning scheme aiming to satisfy quality of service (QoS). In customized physical resource allocation, we formulate this problem with an integer non-linear programming model, which is solved by a heuristic algorithm based on minimum vertex coverage. The proposed algorithm is compared with the existing approaches, without consideration of slice resource constraints via system-level simulations. From the perspective of infrastructure providers, traffic is scheduled over a limited number of active small-cell base stations (sc-BSs) that significantly reduce the system energy consumption and improve the system's spectral efficiency. From the perspective of virtual network operators and mobile users, the proposed approach can guarantee QoS for mobile users and improve user satisfaction.

• Journal of the Korean Society of School Health
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• v.34 no.1
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• pp.76-86
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• 2021

Purpose: This study was conducted to describe the experience of school health teachers in regard to the COVID-19 pandemic in South Korea. Methods: We conducted a qualitative study using content analysis. Ten school health teachers were recruited from 6 elementary schools, 2 middle schools and 2 high schools in Seoul, using purposive sampling. They participated in semi-structured in-depth interviews in person or using an online communication system from January to February, 2021. Interviews were transcribed verbatim and analysed using qualitative content analysis. Results: Three main categories and nine generic categories emerged from the analysis. Firstly, it was discovered that school health teachers had psychological and physical stress to cope with COVID-19 due to the 1) fear of the unexpected infectious disease, 2) burden of having to deal with it alone, 3) breakdown of personal life and physical exhaustion and 4) heavy duty as a health teacher caused by the lack of an organic cooperation system with institutions related to school infectious diseases. Secondly, school health teachers had an increased sense of empowerment in regard to infectious disease management as a result of 1) feeling rewarded and appreciated and 2) gaining confidence and trust in infectious disease management. Finally, school health teachers experienced the urgent need for an effective response strategy for infection control because of the 1) confusion over infectious disease response due to lack of practical manuals applicable to the field as well as training, 2) disappointing response system without an expert response team dedicated to managing infectious diseases in schools, and 3) growing awareness of the need for change. Conclusion: It is expected that school health teachers' experience of COVID-19 will be used as important data for building effective and advanced school infectious disease response systems.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.12
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• pp.819-828
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• 2022

Sensitivity of aircraft sizing depending on battery performance was studied for a generic quad tilt rotor type electric vertical takeoff and landing vehicle. The mission requirements proposed by Uber Elevate and NASA were used for initial sizing, and the calculated gross weight is ranged between 5,000lb and 11,000lb for battery specific energy range of 200-400Wh/kg in pack level and continuous discharge rate range of 4-5C. For the assumed gross weight of 7,000lb, the required battery performance was calculated with two different criteria: available power and energy, and the effects of battery specific energy and discharge rate are analyzed. The maximum discharge rate is also recommended considering failure cases such as one battery pack inoperative and one prop rotor inoperative.

• Journal of the Korean association of regional geographers
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• v.2 no.2
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• pp.1-8
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• 1996

The purpose of this study is to analyse the regional variation of tenancy system in later Yi-Dynasty in Korea. Materials for the analysis are acquired through materials(韓國土地農産調査報告), published in 1905 and agricultural census published in 1912. For the identification of difference of tenancy system between agricultural region, regionalization are conducted through by crop combination. Crop combination structure, using rank of LQ index, was clustered into five generic lesions through cluster analysis. In these contexts, this study has come to following conclusions. There are three types of tenancy system in materials; (1) Doji(賭地) system of which landrent was 1/3 agricultural products. Tenant healed the land tax and seeds. (2) Byoengjak(竝作) system of which landrent was 1/2 agricultural products. Landlords healed the land tax and seeds (3) Jeongaek(定額法) system of which landrent was fixed without relation to annual products. But through the analysis of relationship between agricultural region and tenancy system, a new tenancy system could be identified : Byeongjak(竝作) II system. In this system, landrent was 1/2 of agricultural products, but landlord and tenant shared the landtax and seed in common. In the distribution of these systems, relationship between tenancy system and agricultural regions could be identified. Doji system was distributed in the regions where rice and double cropping was specialized. But Byoeongjak(竝作) system was distributed in the regions where upland crops are specialized and ratio of Paddy field is comparatively low. Especially new types were emenged where ratio of paddy field was very low. These show that increase of productivity of land didn't induce the development of the right of ownership in land. The development of ownership was emerged only on the rice paddy fields. Barley cultivated through double-cropping passed into tenant's possessions. So nominal landrent in paddy field seemed to be raised, but actual landrent was maintained about 1/3 of Products through double cropping. On the contrary, rights of cultivation is developed through double cropping. As double cropping is developed, competition on paddy field between tenants was intensified. Consequently nominal land rent of Paddy fields should be raised.

• Journal of the Korean Society of Systems Engineering
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• v.13 no.2
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• pp.49-56
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• 2017

Implementation of Model-based Systems Engineering(MBSE) depends on a model supporting efficient communication among engineers from various domains. And SysML is designed to create models supporting MBSE but unfortunately, SysML itself is not practical enough to be used in real-world engineering projects. SysML is designed to express generic systems and requires specialized knowledge, so a model written in SysML is less capable of supporting communication between a systems engineer and a sub-system engineer. Domain Specific Languages(DSL) can be a great solution to overcome the weakness of the standard SysML. A SysML based DSL means a customized SysML for a specific engineering domain. Unfortunately, current researches on SysML Domain Specific Language(DSL) for the plant engineering industry are still on the early stage. So as the first step, we have developed our own SysML based Piping & Instrumentation Diagram (P&ID) creation environment and P&ID itself of a specific plant system, using a widely used SysML authoring tool called MagicDraw. P&ID is one of the most critical output during the plant design phase, which contains all information required for the plant construction phase. So a SysML based P&ID has a great potential to enhance the communication among plant engineers of various disciplines.

• Journal of The Korean Association of Information Education
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• v.9 no.2
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• pp.167-176
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• 2005

It has been an important agenda to acquire effective decision making procedure for various issues occurred in education area. As an example, when it comes for the ministry of education to make a decision on such an issue that proper investment, to enhance information of education area, in national wide elementary schools, an effective decision making procedure will aid to establish right way of investment. Currently, the questionnaires gathered from school teachers or the related professional consultants are the only resources in order for making such a critical and important decision. Recently, however, educational, medical, and financial industries are looking forward the best decision making method integrated with rapidly upgraded modern IT technologies using the various resources and tools which they already possess. With this subject in mind, in this paper we present a generic decision making model applying ADALINE neural network. The model can be easily adapted to various problems arising in education area. We proved the model through simulations with realistic sample data.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.1
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• pp.46-54
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• 2013

Recently, the marine leisure industry has begun to make a mark on the growth engines of the Korean economy. Hence, various government research projects are in progress to catch up with the fundamental yacht technologies of advanced countries. Research on the integrated management technologies of sail yachts is carried out as a part of those projects. Work Breakdown Structure (WBS) is a basic architecture for robust and high-level management systems. In this paper, we suggest a product-oriented Yacht Work Breakdown Structure (YWBS). General WBS has a drawback in that it can only follow the targeted purpose, but YWBS allows for a generic WBS approach. This concept allows us to apply WBS to multi-purpose uses. The YWBS is used as an infrastructure in information management and for data relationships in sail yacht management systems. YWBS is designed and managed by a web application, and the system is implemented with a website as a user interface. This application has not only a design function, but also a data transfer function that is based on the Microsoft Silverlight platform, a kind of Rich Internet Application (RIA) technology. Using this application, YWBS designers can communicate with the management system without added tasks like as uploading and updating.

• International Journal of Automotive Technology
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• v.8 no.6
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• pp.731-744
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• 2007

A method for dynamic analysis and design calculation of a Powertrain Mounting System(PMS) including Hydraulic Engine Mounts(HEM) is developed with the aim of controlling powertrain motion and reducing low-frequency vibration in pitch and bounce modes. Here the pitch mode of the powertrain is defined as the mode rotating around the crankshaft of an engine for a transversely mounted powertrain. The powertrain is modeled as a rigid body connected to rigid ground by rubber mounts and/or HEMs. A mount is simplified as a three-dimensional spring with damping elements in its Local Coordinate System(LCS). The relation between force and displacement of each mount in its LCS is usually nonlinear and is simplified as piecewise linear in five ranges in this paper. An equation for estimating displacements of the powertrain center of gravity(C.G.) under static or quasi-static load is developed using Newton's second law, and an iterative algorithm is presented to calculate the displacements. Also an equation for analyzing the dynamic response of the powertrain under ground and engine shake excitations is derived using Newton's second law. Formulae for calculating reaction forces and displacements at each mount are presented. A generic PMS with four rubber mounts or two rubber mounts and two HEMs are used to validate the dynamic analysis and design calculation methods. Calculated displacements of the powertrain C.G. under static or quasi-static loads show that a powertrain motion can meet the displacement limits by properly selecting the stiffness and coordinates of the tuning points of each mount in its LCS using the calculation methods developed in this paper. Simulation results of the dynamic responses of a powertrain C.G. and the reaction forces at mounts demonstrate that resonance peaks can be reduced effectively with HEMs designed on the basis of the proposed methods.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.1
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• pp.39-47
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• 2009

The effects of thermo-solutal convection on mercurous chloride system of ${Hg_2}{Cl_2}$, and Ne during physical vapor transport are numerically investigated for further understanding and insight into essence of transport phenomena, For $10\;K{\le}{\Delta}T{\le}30\;K$, the growth rate slowly increases and, then is decreased gradually until ${\Delta}T$=50 K, The occurrence of this critical point near at ${\Delta}T$=30 K is likely to be due to the effects of thermo-physical properties stronger than the temperature gradient corresponding to driving force for thermal convection. For the range of $10\;Torr{\le}P_B{\le}300\;Torr$, the rate is second order-exponentially decayed with partial pressures of component B, $P_B$. For the range of $5{\le}M_B{\le}200$, the rate is second order-exponentially decayed with a function of molecular weight of component B, $M_B$. Like the case of a partial pressure of component B, the effects of a molecular weight arc: reflected through the binary diffusivity coefficients, which are intimately related with suppressing the convection flow inside the growth enclosure, i,e., transition from convection to diffusion-dominant flow mode as the molecular weight of B increases. The convective mode is near at a ground level, i,e., on earth (1 $g_0$), and the convection is switched to the diffusion mode for $0.1\;g_0{\le}g{\le}10^{-2}g_0$, whereas the diffusion region ranges from $10^{-2}g_0$ up to $10^{-5}g_0$.

• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.41-52
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• 2012

According to 2005 Korea National Health and Nutrition Survey, it has been reported that 32.9% men and 31.8% women have Metabolic syndrome among the population of age 30 and over. The importance of prevention and management is being emphasized in Metabolic syndrome which is a complex disease related to various generic and environmental factors like other chronical disease. In this study we suggest an service based on the data using the system architecture, ontology and Jena2.0 inference engine and organizing the disease-related guideline. The study also arrives at the result through proper interpretation and reasoning process using health management service model based on ontology. The accuracy according to the situation was tested and 930 data samples were selected and experimented. We drew a conclusion that the much personalized data is available, the more personalized services are possible. Since the risk factors of Metabolic syndrome are various, it would be effective to suggest customized services based on various personalized data.