• International Journal of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.206-211
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• 2022

As the level of consumption is improved and cultural life is pursued, the consumer's consciousness structure is rapidly changing, and the demand for product selection level, variety, and quality is becoming more diverse. The restaurant economy is falling due to the prolonged COVID-19, the economic recession, income decline, and changes in population structure and lifestyle, but the Meal- kit market is growing rapidly. This study aims to identify the consumer perception of Meal-kit, which is rapidly growing as an alternative to existing meals in the fields of dining out, food, and distribution due to the development of technology and social environment using big data. As a result of the analysis, the keywords with the highest frequency of appearance were in the order of Meal-kit, Cooking, Product, Launching, and Market and were divided into 8 groups through the CONCOR analysis. We want to identify consumer trends related to the key keywords of Meal-kit, present effective data related to Meal-kit demand for Meal-kit specialized companies, and provide implications for establishing marketing strategies for differentiated competitive advantage.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.3
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• pp.1047-1062
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• 2022

Differential power analysis (DPA) is disturbed by ghost peaks. There is a phenomenon that the mean absolute difference (MAD) value of the wrong key is higher than the correct key. We propose a compressed key guessing space (CKGS) scheme to solve this problem and analyze the AES algorithm. The DPA based on this scheme is named CKGS-DPA. Unlike traditional DPA, the CKGS-DPA uses two power leakage points for a combined attack. The first power leakage point is used to determine the key candidate interval, and the second is used for the final attack. First, we study the law of MAD values distribution when the attack point is AddRoundKey and explain why this point is not suitable for DPA. According to this law, we modify the selection function to change the distribution of MAD values. Then a key-related value screening algorithm is proposed to obtain key information. Finally, we construct two key candidate intervals of size 16 and reduce the key guessing space of the SubBytes attack from 256 to 32. Simulation experimental results show that CKGS-DPA reduces the power traces demand by 25% compared with DPA. Experiments performed on the ASCAD dataset show that CKGS-DPA reduces the power traces demand by at least 41% compared with DPA.

• Journal of Distribution Science
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• v.20 no.11
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• pp.109-120
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• 2022

Purpose: We would like to identify the appropriate size of stores in the commercial district suitable for the era of low growth. In addition, it is intended to present alternatives to prevent gentrification along with measures to revitalize commercial districts according to the selection of appropriate stores. Research design, data and methodology: The importance and commercial district usage patterns were identified through surveys by consumers and sellers. the demand and size of the commercial area were calculated based on the floating population and resident registration population. In addition, based on this, through metric analysis, the importance of the business district activation plan and what important matters can prevent gentrification were analyzed. Result: In this the study, 555 stores are currently operating in the target area, but it is seen as a commercial district with a scale that can operate 136 stores and 938 stores. In addition, it was analyzed that the Commercial Lease Protection Act needs to be strengthened to prevent gentrification. Conclusions: Due to the nature of small and medium-sized cities in Korea, commercial districts that have once lost their resilience must take much effort to find vitality. It is believed that local commercial districts will have resilience when diagnosis and recovery measures are adequately presented.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.937-944
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• 2022

Electric vehicles (EVs) have been growing to reduce energy consumption and greenhouse gas (GHG) emissions in the transportation sector. The increasing number of EVs requires adequate recharging infrastructure, and at the same time, adopts low- or zero-emission electricity production because the GHG emissions are highly dependent on primary sources of electricity production. Although previous research has studied solar photovoltaic (PV) -integrated EV charging stations, it is challenging to optimize spatial areas between where the charging stations are required and where the renewable energy sources (i.e., solar photovoltaic (PV)) are accessible. Therefore, the primary objective of this research is to support decisions of siting EV charging stations using a spatial data clustering method integrated with Geographic Information System (GIS). This research explores spatial relationships of PV power outputs (i.e., supply) and traffic flow (i.e., demand) and tests a community in the state of Indiana, USA for optimal sitting of EV charging stations. Under the assumption that EV charging stations should be placed where the potential electricity production and traffic flow are high to match supply and demand, this research identified three areas for installing EV charging stations powered by rooftop PV in the study area. The proposed strategies will drive the transition of existing energy infrastructure into decentralized power systems. This research will ultimately contribute to enhancing economic efficiency and environmental sustainability by enabling significant reductions in electricity distribution loss and GHG emissions driven by transportation energy.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1135-1144
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• 2024

With the increasing ratio of renewables in the grid, a low-carbon and stable base load source that also is capable of load tracking is in demand. Sodium cooled fast reactors (SFRs) coupled to thermal heat storage system (THS) is a strong candidate for the need. This research focuses on the designing and performance validation of a two-tank THS based on molten salt to integrate with a 280 MW_th sodium cooled fast reactor. Designing of the THS includes the vital component, sodium-to-salt heat exchanger which is a technology gap that needs to be filled, and designing and parameter selection of the tanks and related pumps. Modeling of the designed THS is conducted followed by the description of operation strategies and control logics of the THS. Finally, the dynamic simulation of the designed THS is conducted based on Fortran. Results show, the proposed power system meets the need of the design requirements to store heat for 18 h during a day and provide 500 MW_th for peak demand for the rest of the day.

• Annual Conference of KIPS
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• 2007.05a
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• pp.1205-1208
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• 2007

모바일 애드혹 네트워크는 기존의 셀룰러 네트워크와는 달리 고정된 기지국이 존재하지 않고 모바일 노드들만으로 구성된 네트워크이다. 모바일 애드혹 네트워크의 각각의 노드들은 제한된 자원과 한정된 용량을 가진 배터리로 동작한다. 만일 이 배터리를 모두 소모하게 된다면 중간 노드들이 다운이 되고, 결과적으로 전체 네트워크가 단절되는 문제가 발생할 수 있다. 기존의 전송 전력을 고려하여 경로를 설정하는 기법인 CLUSTERPOW는 노드 간에 연결되는 전송 전력을 최소화함으로써 데이터 전송 시 소비되는 전력을 줄이고자 하였다. 그러나 이 기법은 proactive 방식의 라우팅 프로토콜에는 적합하나 reactive 방식의 라우팅 프로토콜에는 적합하지 않다. 따라서 본 논문에서는 reactive 방식의 특성에 맞는 전송 전력 설정 기법인 FSRS(Fast Search Reverse Setting) 기법을 제안하였다. FSRS 기법은 reactive 방식에서 사용하는 컨트롤 패킷 플라딩을 사용한 경로 설정에서의 오버헤드를 줄이고자 클러스터 간 플라딩을 통해 목적지 노드를 빠르게 찾고 한정된 클러스터 간 경로를 통해 전송 전력을 고려한 세부적인 경로를 설정한다. FSRS 기법은 기존의 CLUSTERPOW 기법과 마찬가지로 효율적인 전송 전력으로 경로를 설정하였으며 또한 네트워크 생존 시간을 CLUSTERPOW보다 평균 43% 연장시켰다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.921-940
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• 2015

In this paper, we investigate the multi-resource allocation problem, a unique feature of which is that the multiple resources can compensate each other while achieving the desired system performance. In particular, power and time allocations are jointly optimized with the target of energy efficiency under the resource-limited constraints. Different from previous studies on the power-time tradeoff, we consider a multi-server case where the concurrent serving users are quantitatively restricted. Therefore user selection is investigated accompanying the resource allocation, making the power-time tradeoff occur not only between the users in the same server but also in different servers. The complex multivariate optimization problem can be modeled as a variant of 2-Dimension Bin Packing Problem (V2D-BPP), which is a joint non-linear and integer programming problem. Though we use state decomposition model to transform it into a convex optimization problem, the variables are still coupled. Therefore, we propose an Iterative Dual Optimization (IDO) algorithm to obtain its optimal solution. Simulations show that the joint multi-resource allocation algorithm outperforms two existing non-joint algorithms from the perspective of energy efficiency.

• Journal of Information Technology Applications and Management
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• v.18 no.2
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• pp.1-21
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• 2011

In this era of convergence, which is characterized by the integration and combination of technology and industries, broadcasting and communications, offline and online, and devices and services, the content industry is also experiencing rapid changes including inter-genre exchange, the creation of new industries, and customized demand. Specifically, IT-based digital content industries such as the online game, e-book, mobile contents and web portal industries are no longer restricted to the boundaries of video, music and games but are being expanded into the realms of education, medicine, fashion and sports thanks to CT innovation of 3D, CG, AR/VR, VFX, etc. As such, various countries have come to recognize the convergent content industry as a new growth engine that will pick up where the IT industry left off, and are forming policies for its development accordingly. This research aims to optimize the system of content taxonomy which is currently genre-focused and unable to support technological development and convergence, and to discover and select star contents to be rigorously developed with governmental support. In this paper, 20 star contents in 8 areas were selected, and these are expected to create tremendous cultural and economic value through ongoing technological and industrial development.

• Journal of the Korea Computer Industry Society
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• v.5 no.8
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• pp.811-818
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• 2004

The spreading of internet, combined with the computerization of industry and the life whole has created an incereased demand on the private life protection and information portection, but due to the lack of specialty manpower on the information protection industry field there are many difficulties. Therefore, in this paper a curriculum for an information protection specialty manpower training is proposed. The proposed curriculum indispensability 1,2 and classified with a selection 1,2 and classified with a selection 1,2. The information protection application field into 9 segments of domains, and to carry out the curriculum in a ring structure. The curriculum based on the information security field's 9 domains and related field practical business, and the course offered after graduation to deepen the specialty, need to be carried out by each domain in order to continuously carry out the information security deepening process.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.12
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• pp.28-36
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• 2012

Augmentation of existing EHV substations located in hilly terrain and at high altitude require many different considerations as compared to substations located in plain areas and at lower altitude. Owing to high altitude and steep terrain, meticulous engineering and preparations are required, considering the actual available space at the existing substation. Historical fault events too must be considered to enhance reliability and performance of the substation equipment. This paper proposes ways to augment the existing 2 banks of 20MVA, 220/66kV power transformers ($3{\times}6.67MVA$, single-phase) to $2{\times}50$/63MVA, 220/66kV power transformers to meet continuously increasing demand of the capital city over the next 20 years. Upgrading and augmentation of existing substations, especially the main transformers and associated equipment, require replacement with minimum or no disturbance to the existing power supply system. Considerations should also be made during engineering and design, the operational flexibilities, maintenance aspects, future expandability and value addition, in terms of reliability and space usage of the existing substation.