• Journal of Power Electronics
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• 제15권1호
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• pp.256-267
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• 2015

Grid-connected transformerless photovoltaic (PV) inverters (TPVIs) are increasingly dominating the market due to their higher efficiency, lower cost, lighter weight, and reduced size when compared to their transformer based counterparts. However, due to the lack of galvanic isolation in the low voltage grid interconnections of these inverters, the PV systems become vulnerable to leakage currents flowing through the grounded star point of the distribution transformer, the earth, and the distributed parasitic capacitance of the PV modules. These leakage currents are prohibitive, since they constitute an issue for safety, reliability, protection coordination, electromagnetic compatibility, and module lifetime. This paper investigates a wide range of multi-kW range power rating TPVI topologies and classifies them in terms of their leakage current attributes. This systematic classification places most topologies under a small number of classes with basic leakage current attributes. Thus, understanding and evaluating these topologies becomes an easy task. In addition, based on these observations, new topologies with reduced leakage current characteristics are proposed in this paper. Furthermore, the important efficiency and cost determining characteristics of converters are studied to allow design engineers to include cost and efficiency as deciding factors in selecting a converter topology for PV applications.

• 한국정보처리학회논문지
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• 제6권5호
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• pp.1241-1252
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• 1999

It is proposed in TINA, the open information telecommunication network architecture, that the definition of object group which is collection of objects provides a decrease of complex networking and a facility of object managing by service executing of application on distributed computing environment. Based on a new distributed object group model[13] we have been researched according to TINA specification, this paper proposed the object group model with the scheduler object and objects management mechanisms that can support real-time services on CORBA. To do this, we described the definition of object grouping and the requirements to suggest the object group model supporting real-time service, designed the object group structure and functional components containing in an object group using James Rumbaugh's modelling[12], and showed a class diagram of components in an object group. This paper designed IDLs of an object group manager and scheduler among the components, and finally showed the procedures of management and service interconnections between objects in the different object groups vi ETD.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.149-153
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• 2003

Chemical mechanical polishing (CMP) technology for global planarization of multi-level inter-connection structure has been widely studied for the next generation devices. CMP process has been paid attention to planarized pre-metal dielectric (PMD), inter-layer dielectric (ILD) interconnections. Expecially, shallow trench isolation (STI) used to CMP process on essential. Recently, the direct STI-CMP process without the conventional complex reverse moat etch process has established by using slurry additive with the high selectivity between $SiO_2$ and $Si_3N_4$ films for the purpose of process simplification and n-situ end point detection(EPD). However, STI-CMP process has various defects such as nitride residue, tom oxide and damage of silicon active region. To solve these problems, in this paper, we studied the planarization characteristics using a high selectivity slurry(HSS). As our experimental results, it was possible to achieve a global planarization and STI-CMP process could be dramatically simplified. Also we estimated the reliability through the repeated tests with the optimized process conditions in order to identify the reproducibility of HSS STI-CMP process.

• Journal of Information Science Theory and Practice
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• 제3권1호
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• pp.50-65
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• 2015

Recently US/EU governments are utilizing nanotechnology as a key catalyst to support national innovation policies with economic recovery goals. US/EU nano policies have been serving as a global model to various countries, including Korea. So the authors initially seek to understand US/EU national innovation policy interconnections, and then find the role of nanotechnology development within. To strengthen national policy coherence, nanotechnology development strategies are under evolution as an innovation catalyst for promoting commercialization. To strategically support nano commercialization, EHS (Environmental, Health, Safety) and informatics are invested as priority fields to strengthen social acceptance and sustainability of nano enabled products. The current study explores US/EU national innovation policies including nano commercialization, EHS, and Informatics. Then obtained results are utilized to analyze weaknesses of Korean innovation systems of connecting creative economy and nanotechnology development policies. Then ongoing improvements are summarized focusing on EHS and informatics, which are currently prominent issues in international nanotechnology development.

• 한국표면공학회지
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• 제48권5호
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• pp.233-237
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• 2015

In order to investigate the potassium (K) gettering, Al-1%Si/$SiO_2$/PSG multilevel thin films were fabricated. Al-1%Si thin films and $SiO_2$/PSG passivations were deposited by using DC magnetron sputter techniques and APCVD (atmosphere pressure chemical vapor deposition), respectively. Heat treatment was carried out at $300^{\circ}C$ for 5 h in air. SIMS (secondary ion mass spectrometry) depth profiling analysis was used to determine the distribution of K, Al, Si, P, and other elements throughout the $SiO_2$/PSG passivated Al-1%Si thin film interconnections. Potassium peaks were observed throughout the $SiO_2$/PSG passivation layers, and especially the interface gettering at the $SiO_2$/PSG and at the Al-1%Si/$SiO_2$ interfaces was observed. Potassium gettering in Al-1%Si/$SiO_2$/PSG multilevel thin films is considered to be caused by a segregation type of gettering.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.163-163
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• 2019

The rapidly growing global population increases the awareness of water, energy, and food security worldwide. The concept of Water, Energy, and Food nexus (hereafter, WEF nexus) has been widely introduced as a new resources management concept that integrate the water, energy, and food in a single management framework. Recently, WEF nexus analyzes not only the interconnections among the resources, but also considers the external factors (such as environment, climate change, policy, finance, etc) to enhance the resources sustainability by proper understanding of their relations. A nation-level resources management is quite complex task since multiple regions (e.g., watersheds, cities, and counties) with different characteristics are spatially interconnected and transfer the resources each other. This study proposes a multiple region WEF nexus simulation and transfer model. The model is equipped with three simulation modules, such as local nexus simulation module, regional resources transfer module, and optimal investment planning module. The model intends to determine an optimal capital investment plan (CIP), such as build-up of power plants, water/waste water treatment plants, farmland development and to determine W-E-F import/export decisions among areas. The objective is to maximize overall resources sustainability while minimize financial cost. For demonstration, the proposed model is applied to a semi-hypothetical study area with three different characterized cities. It is expected the model can be used as a decision support tool for a long-term resources management planning process.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.153-153
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• 2018

Water-Energy-Food (WEF) nexus is a new holistic resources management concept that considers the interconnections among resources for sustainable resources planning and management. The current challenge is to fulfill the required demand in the lack of available resources. A traditional way to provide more available resource is by increase in production, but it caused increment of indirect demand of other interlinked resources. Importing resources from other area (where local supply is redundant) is another option to secure local resources with additional economic expenditure. The WEF nexus-trading model adapts the previously developed nationwide nexus simulation model with additional input parameters and functions to simulate trading scenarios. In general, the analysis starts with the quantification of local resources deficit (potential importing amount) and redundancy (potential exporting amount) of each area. Then, a trade module is initiated by determining possible donor area and importation amount. Finally, the nexus simulation for all area is re-run to determine final resources supply-demand results including the trading amount. The trade option provides an opportunity to meet local demands without draining local resources. However, the production capability of donor area may limit the importation amount. The newly developed trade option allows more alternatives for stakeholders to determine resources management plans.

• 전기학회논문지
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• 제67권12호
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• pp.1705-1710
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• 2018

This paper deals with an analysis of the causes of over current relay(OCR) misoperation in power system with distributed generations(DG). In general, Y-D and Y-Y-D transformer connections are used for grid interconnection of DG. According to the interconnection guideline, the neutral point on Y side should be grounded. However, these transformer connections can lead to OCR misoperation as well as over current ground relay(OCGR) misoperation. Several researches have addressed the OCGR misoperation due to the interaction between transformer connections and zero-sequence voltage of distribution system. Recently, a misoperation of OCR at the point of DG interconnection to the utility system has been also reported. With increasing the interconnections of DG, such OCR as well as OCGR misoperations are expected to increase. In this paper, PSCAD/EMTDC modeling including DG interconnection transformer was performed and various case studies was carried out for identifying the cause of OCR misoperation.

• 보존과학회지
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• 제37권1호
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• pp.1-12
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• 2021

In the digital era, large archives of information and Internet accessibility make information search, including image search, easier and affordable, even from remote locations. Information transmission and sharing can be performed instantly, at any moment. In the case of images, there are risks of transmitting and recklessly sharing intentionally modified images. Such modified images can also be transmitted and used as an additional source of information by followers. In this study, historical portraits of Yu Kil-Chun are shown, who was the first Korean student to study in both Japan and the United States. He was an intellectual, writer, politician, and independence activist of Korea's late Joseon Dynasty. Using image processing software, the portrait images were compared to investigate aging effects and artificial modifications. Statistics of red (R), green (G), blue (B), and L^*, a^*, and b^* values of every pixel in the selected identical areas of the portraits were compared to identify possible causes of variations, including aging effects and artificial modifications. Sepia toning, used in black and white photographs until the 1930s, and modern digital sepia toning can be very confusing owing to their aging effects. The importance of preservation of physical copies and preservation of context (interconnections between data and between documents) is discussed from archiving and conservation science perspectives.

• International Journal of Computer Science & Network Security
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• 제21권4호
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• pp.84-92
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• 2021

Care services are a significant asset in human life. Care in its overall nature focuses on human needs and covers several aspects such as health care, homes, personal care, and education. In fact, care deals with many dimensions: physical, psychological, and social interconnections. Very little information is available on estimating the cost of care services that provided to orphans and abandoned children. Prediction of the cost of the care system delivered by governmental or non-governmental organizations to support orphans and abandoned children is increasingly needed. The purpose of this study is to analyze the care cost for orphanage organizations in Saudi Arabia to forecast the cost as well as explore the most influence factor on the cost. By using business analytic process that applied statistical and machine learning techniques, we proposed a model includes simple linear regression, Naive Bayes classifier, and Random Forest algorithms. The finding of our predictive model shows that Naive Bayes has addressed the highest accuracy equals to 87% in predicting the total care cost. Our model offers predictive approach in the perspective of business analytics.