• Smart Structures and Systems
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• v.6 no.5_6
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• pp.579-593
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• 2010

Low-power radio frequency (RF) chip transceiver technology and the associated structural health monitoring platforms have matured recently to enable high-rate, lossless transmission of measurement data across large-scale sensor networks. The intrinsic value of these advanced capabilities is the allowance for high-quality, rapid operational modal analysis of in-service structures using distributed accelerometers to experimentally characterize the dynamic response. From the analysis afforded through these dynamic data sets, structural identification techniques can then be utilized to develop a well calibrated finite element (FE) model of the structure for baseline development, extended analytical structural evaluation, and load response assessment. This paper presents a case study in which operational modal analysis is performed on a three-span prestressed reinforced concrete bridge using a wireless sensor network. The low-power wireless platform deployed supported a high-rate, lossless transmission protocol enabling real-time remote acquisition of the vibration response as recorded by twenty-nine accelerometers at a 256 Sps sampling rate. Several instrumentation layouts were utilized to assess the global multi-span response using a stationary sensor array as well as the spatially refined response of a single span using roving sensors and reference-based techniques. Subsequent structural identification using FE modeling and iterative updating through comparison with the experimental analysis is then documented to demonstrate the inherent value in dynamic response measurement across structural systems using high-rate wireless sensor networks.

• Land and Housing Review
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• v.12 no.4
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• pp.15-30
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• 2021

Korean urban development cooperation is gradually expanding into Latin America and the Caribbean (LAC) region, but strategies to encourage domestic market players to participate are insufficient. This paper investigated the Colombian urban planning system, urban development projects, and Korean projects in Colombia, which leads to implications for international cooperation in LAC. This research, first, compares the national and regional urban planning systems of Colombian major cities, Bogotá and Medellín. Second, case studies are carried out with a land readjustment project, a Macro project for large-scale public rental housing supply, and urban development cooperation between Korea and Colombia. By doing so, the role and the directions for Korean urban development cooperation with LAC such as Colombia are discussed and proposed. The findings suggest, first, aid projects through Official Development Assistance (ODA) should establish urban networks in recipient countries. Second, it is necessary to understand the financing structure for urban development cooperation projects that are different from infrastructure projects. Third, the successful case of urban development cooperation should be demonstrated by making the development period and size optimal and manageable.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.12
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• pp.1688-1696
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• 2020

The paradigm of Internet-of-things(IoT) systems is changing from a cloud-based system to an edge-based system to solve delays caused by network congestion, server overload and security issues due to data transmission. However, edge-based IoT systems have fatal weaknesses such as lack of performance and flexibility due to various limitations. To improve performance, application-specific hardware can be implemented in the edge device, but performance cannot be improved except for specific applications due to a fixed function. This paper introduces a edge-centric metamorphic IoT(mIoT) platform that can use a variety of hardware through on-demand partial reconfiguration despite the limited hardware resources of the edge device, so we can increase the performance and flexibility of the edge device. According to the experimental results, the edge-centric mIoT platform that executes the reconfiguration algorithm at the edge was able to reduce the number of server accesses by up to 82.2% compared to previous studies in which the reconfiguration algorithm was executed on the server.

• International Area Studies Review
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• v.21 no.2
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• pp.171-196
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• 2017

This study employed the Analytical Hierarchy Process (AHP) methodology with the enhancement of the competitiveness of Vietnamese commercial banks set as the overall goal of the model. Analysis of the survey questionnaire based on pair-wise comparisons and collected from experts in the field of banking led to three significant findings. First, banking safety is the most important evaluation criteria for the competitiveness of local commercial banks in Vietnam, followed by operating efficiency, intangible values and large scale. Second, in order to achieve the overall goal of enhancing competitiveness for local banks, securing healthy financial conditions should be made the priority. Effective management systems, strategic human resource planning and high-quality products and services all show strong connections to achieving the evaluation criteria. Third, the study found that bad debt settlement is essential in obtaining healthy financial conditions. In order to introduce effective management systems as well as high-quality products and services, technological advances are very important. Improving the quality of executives and staff is imperative for strategic human resource planning purposes.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.6
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• pp.192-207
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• 2020

In industrial fields like big factories, efficient management of resources is critical in terms of time and expense. So, inefficient management of resources leads to additional costs. Nevertheless, in many cases, there is no proper system to manage resources. This study proposes a system to manage and track large-scale resources efficiently. We attached Bluetooth 5.0-based beacons to our target resources to track them in real time, and by saving their transportation data we can understand flows of resources. Also, we applied a diagonal survey method to estimate the location of beacons so we are able to build an efficient and accurate system. As a result, We achieve 47% more accurate results than traditional trilateration method.

• Smart Structures and Systems
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• v.30 no.3
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• pp.327-332
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• 2022

In building envelope, transparent components play an important role. The structural glazing systems are the weak element of the casing in terms of mechanical resistance, thermal and acoustic insulation. In the present work, new structural glass panels with granular aerogel in interspace were investigated from different points of view. In particular, the mechanical characterization was carried out in order to assess the resistance to bending of the single glazing pane. To this end, a special instrument system was built to define an alternative configuration of the coaxial double ring test, able to predict the fracture strength of glass large samples (400 × 400 mm) without overpressure. The thermal and lighting performance of an innovative double-glazing façade with granular aerogel was evaluated. An experimental campaign at pilot scale was developed: it is composed of two boxes of about 1.60 × 2 m² and 2 m high together with an external weather station. The rooms, identical in terms of size, construction materials, and orientation, are equipped with a two-wing window in the south wall surface: the first one has a standard glazing solution (double glazing with air in interspace), the second room is equipped with the innovative double-glazing system with aerogel. The indoor mean air temperature and the surface temperature of the glass panes were monitored together with the illuminance data for the lighting characterization. Finally, a brief energy characterization of the performance of the material was carried out by means of dynamic simulation models when the proposed solution is applied to real case studies.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.4
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• pp.50-61
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• 2022

Snow, rain, fog, and particulate matter interfere with the vehicle driver's vision, which causes a non-secure safety distance and an increase in speed deviation, causing repetitive large-scale traffic accidents. This study developed a road environment sensor capable of measuring 11 types of fog, snow, rain, temperature, humidity, direction of wind, speed of wind, Insolation, atmospheric pressure, fine particles, rainfall, etc. and compared the visibility measured by the infrared signal value of the development sensor. The relationship between the existing fog visibility sensor and the development sensor measurement was derived from data measured at a visibility of 500m or less that directly affects road safety.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.7
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• pp.2257-2285
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• 2022

Cyber-physical systems (CPS) have been growing exponentially due to improved cloud-datacenter infrastructure-as-a-service (CDIaaS). Incremental expandability (scalability), Quality of Service (QoS) performance, and reliability are currently the automation focus on healthy Tier 4 CDIaaS. However, stable QoS is yet to be fully addressed in Cyber-physical data centers (CP-DCS). Also, balanced agility and flexibility for the application workloads need urgent attention. There is a need for a resilient and fault-tolerance scheme in terms of CPS routing service including Pod cluster reliability analytics that meets QoS requirements. Motivated by these concerns, our contributions are fourfold. First, a Distributed Non-Recursive Cloud Model (DNRCM) is proposed to support cyber-physical workloads for remote lab activities. Second, an efficient QoS stability model with Routh-Hurwitz criteria is established. Third, an evaluation of the CDIaaS DCN topology is validated for handling large-scale, traffic workloads. Network Function Virtualization (NFV) with Floodlight SDN controllers was adopted for the implementation of DNRCM with embedded rule-base in Open vSwitch engines. Fourth, QoS evaluation is carried out experimentally. Considering the non-recursive queuing delays with SDN isolation (logical), a lower queuing delay (19.65%) is observed. Without logical isolation, the average queuing delay is 80.34%. Without logical resource isolation, the fault tolerance yields 33.55%, while with logical isolation, it yields 66.44%. In terms of throughput, DNRCM, recursive BCube, and DCell offered 38.30%, 36.37%, and 25.53% respectively. Similarly, the DNRCM had an improved incremental scalability profile of 40.00%, while BCube and Recursive DCell had 33.33%, and 26.67% respectively. In terms of service availability, the DNRCM offered 52.10% compared with recursive BCube and DCell which yielded 34.72% and 13.18% respectively. The average delays obtained for DNRCM, recursive BCube, and DCell are 32.81%, 33.44%, and 33.75% respectively. Finally, workload utilization for DNRCM, recursive BCube, and DCell yielded 50.28%, 27.93%, and 21.79% respectively.

• Journal of Korea Society of Industrial Information Systems
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• v.28 no.2
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• pp.21-30
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• 2023

As the adoption and high-performance enhancement of Electric Vehicles continue, the demand for high-output motors and high-capacity Magnetizer for producing large-scale IPMSM is increasing. The maximum peak current of the magnetization and the capacitor discharge time, which are important factors in the magnetization process, are determined by the circuit constants of the magnetizer. In this paper, we analyze the magnetizing system using MATLAB SIMULINK to design the circuit constant of the magnetizing yoke for magnetizing design and present the design procedure for Design the circuit constant. As a result, the parameters of the magnetizing yoke were derived to be 0.015[ohm] and 0.035[mH] based on the capacitance of 15,000[uF] and voltage of 5,000[V].

• Convergence Security Journal
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• v.22 no.1
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• pp.11-17
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• 2022

Cyber attacks on national infrastructure, including large-scale power outages in Ukraine, have continued in recent years. As a result, ICS-CERT vulnerabilities have doubled compared to last year, and vulnerabilities to industrial control systems are increasing day by day. Most control system operators develop vulnerability countermeasures based on the vulnerability information sources provided by ICS-CERT in the United States. However, it is not applicable to the security of domestic control systems because it does not provide weaknesses in Korean manufacturers' products. Therefore, this study presents a vulnerability analysis framework that integrates CVE, CWE, CAPE, and CPE information related to the vulnerability based on ICS-CERT information (1843 cases). It also identifies assets of nuclear facilities by using CPE information and analyzes vulnerabilities using CVE and ICS-CERT. In the past, only 8% of ICS-CERT's vulnerability information was searched for information on any domestic nuclear facility during vulnerability analysis, but more than 70% of the vulnerability information could be searched using the proposed methodology.