• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.11
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• pp.57-68
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• 2013

The market for distributed power generation based on renewable energy is increasing, particularly for standalone mini-grid applications in developing countries with limited energy resources. Stand-alone power systems (SAPS) are of special interest combined with renewable energy design in areas not connected to the electric grid. Traditionally, such systems have been powered by diesel engine generator sets (DEGS), but also hybrid systems with photovoltaic and/or wind energy conversion systems (WECS) are becoming quite common nowadays. Hybrid energy systems can now be used to generate energy consumed in remote areas and stand-alone microgrids. This paper describes the design, simulation and feasibility study of a hybrid energy system for a stand-alone power system. A simulated model is developed to investigate the design and performance of stand-alone hydrogen renewable energy systems. The analysis presented here is based on transient system simulation program (TRNSYS) with realistic ventilation load of a large store. Design of a hybrid energy system is site specific and depends on the resources available and the load demand.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.74-78
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• 2009

Efficient reasoning has become important for improving the performance of ontology systems as the size of ontology grows. In this paper, we introduce a method that efficiently performs reasoning of RDFS entailment rules (i.e., rdfs7 and rdfs9 rules) and OWL inverse rule using views in the DBMS-based triple sotre. Reasoning is performed by replacing reasoning rules with the corresponding view definition and storing RDF triples into the structured triple tables. When processing queries, the views is referred instead of original tables. In this way, we can reduce the time needed for reasoning and also obtain the space-efficiency of the triple store.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.1
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• pp.15-22
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• 2014

Delay-Tolerant Network employs message forwarding based on a Store, Carry and Forward method to conquer no guarantee of continue connectivity. For this reason, a lot of DTN routing scheme have been proposed recently. message forwarding is an important research issue in delay-tolerant network and In this paper, we propose a efficiency DTN routing scheme using node's social relation and expanded Ego-network betweenness centrality. Our simulation results show that it is more efficient to message delivery cost than Epidemic routing, Friendship routing while it has a little performance degradation of message delivery ratio.

• Journal of the Korean Society of Costume
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• v.53 no.7
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• pp.29-36
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• 2003

The purposes of this syudy were to identify the factors of perceived risk, satisfaction, and intention on rental clothing. The subjects were 767 adults residing in Jeonbuk province. The research was made from February 20 to March 19, 2003. Fof data analysis. frequencies, percentages, mean, and standard deviations were calculated. Also, factor analysis and stepwise multiple-regression analysis were done. The results were as follows: 1. Approximately half of the respondents had experiences of rental clothing, and the most frequent items were wedding dress, degree gown, performance dress, and sports wear in descending order. 2. The factors of perceived risk of rental clothing were divided into lost, appropriateness, and damage, and total variance was 62.51%. The perceived risk about damage of rental clothing was the highest, and lost was the lowest. 3. The factors of rental clothing satisfaction were divided into appearances, store status, function, and fitness, and total variance was 59.96%. The satisfaction of function of rental clothing was the highest, and the store status was the lowest. 4. The intention on rental clothing was high in case of higher interest in rental clothing, higher educational level. more experiences in rental clothing, lower perceived risk of damage on the rental clothing, and younger person, and these variables explained 54.00% of the intention on rental clothing.

• Spatial Information Research
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• v.18 no.1
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• pp.11-17
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• 2010

The present study attempts to provide the practical methodology to determine the spatial boundary of trade area, not depending on conventional circle-based regional analysis, but adopting dimension-diverging conception based on GIS and road connectivity by exemplifying a large-scale discount store with an outlook to enhance accuracy and reliability in trade area analyzing. Unlike the preliminary researches frequently relying on circular form of interpretation which were not likely to exclude obstacles blocking the accessibility to trade areas, the method suggested by the study is to suggest an alternative way for demarcating the trade areas more practically with better access by excluding in-between obstacles. Finally, we show verification of proposed cost models and performance by join strategy.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.26 no.2
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• pp.85-92
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• 2020

In this study, the relationship between packaging design and logistics efficiency raised in prior research was to be conducted through empirical analysis in terms of SCM efficiency. The main research contents were carried out in the pursuit of efficiency of the relevant store operation, relationship with SCM efficiency aspects, resolution of differences in recognition between manufacturers and distributors, establishment of automated systems for RRP production facilities and processes in the manufacturer's facilities, logistics costs, environment and quality safety, and promotion of RRP through the manufacturer's packaging system. As a result of the verification of SCM efficiency aspects through this study, logistics efficiency will be reduced in the case of the packaging system or delivery system, where only the operational efficiency of the store is the top priority(χ² = 178.500, p < 0.001). This is because of the strong interaction between packaging and supply chain activities, many packaging systems affect the performance criteria of the supply chain, and the content that packaging personnel should ensure that the packaging system meets other essential requirements while meeting the primary goal of protecting the product is also a result consistent with the preceding study. An analysis of whether the RRP promotion through the manufacturer's packaging system would result in improved loading efficiency showed that there was a statistically meaningful difference at a significant level of 0.000, as χ² = 140.133.

• IEMEK Journal of Embedded Systems and Applications
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• v.7 no.1
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• pp.1-7
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• 2012

A Smartphone has an ability accessing Internet by URL stored in NFC(Near Field Communication) Tag for storing the information of items, blogs and web pages. Because the system works through the Internet with URL, however, it needs to pay some costs like communication fee and time. If we can store the web page on the tags, we can save the communication overhead. But they have too small memory to store it. In this paper, we introduce the Micro-Webpage technology which can be stored in NFC tag or QR(Quick Response) code. To make a Micro-Webpage, we remove control tags from the web page to leave a user original content. The removed control tags are stored in our smartphone application as a template. The user content is also compressed to a smaller one by an lossless compression algorithm. When a tag is read, the stored content is decompressed and, it is combined with the template to make the original web page. We have implemented a prototype of Micro-Webpage system on Android platform and confirmed that the prototype has reasonable performance improvements in saving memory and loading web page time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.466-483
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• 2017

Zen Cart is an open-source online store management system. It is used all over the world because of its stability and safety. Today, Zen Cart's session security mechanism is mainly used to verify user agents and check IP addresses. However, the security in verifying the user agent is lower and checking the IP address can affect the user's experience. This paper, which is based on the idea of session protection as proposed by Ben Adida, takes advantage of the HTML5's sessionStorage property to store the shared keys that are used in HMAC-SHA256 encryption. Moreover, the request path, current timestamp, and parameter are encrypted by using HMAC-SHA256 in the client. The client then submits the result to the web server as per request. Finally, the web server recalculates the HMAC-SHA256 value to validate the request by comparing it with the submitted value. In this way, the Zen Cart's open-source system is reinforced. Owing to the security and integrity of the HMAC-SHA256 algorithm, it can effectively protect the session security. Analysis and experimental results show that this mechanism can effectively protect the session security of Zen Cart without affecting the original performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.8
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• pp.3542-3566
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• 2018

In this paper, we investigate a buffer-aided wireless powered cooperative communication network (WPCCN), in which the source and relay harvest the energy from a dedicated power beacon via wireless energy transfer, then the source transmits the data to the destination through the relay. Both the source and relay are equipped with an energy buffer to store the harvested energy in the energy transfer stage. In addition, the relay is equipped with a data buffer and can temporarily store the received information. Considering the buffer-aided WPCCN, we propose two buffer-aided relaying protocols, which named as the buffer-aided harvest-then-transmit (HtT) protocol and the buffer-aided joint mode selection and power allocation (JMSPA) protocol, respectively. For the buffer-aided HtT protocol, the time-averaged achievable rate is obtained in closed form. For the buffer-aided JMSPA protocol, the optimal adaptive mode selection scheme and power allocation scheme, which jointly maximize the time-averaged throughput of system, are obtained by employing the Lyapunov optimization theory. Furthermore, we drive the theoretical bounds on the time-averaged achievable rate and time-averaged delay, then present the throughput-delay tradeoff achieved by the joint JMSPA protocol. Simulation results validate the throughput performance gain of the proposed buffer-aided relaying protocols and verify the theoretical analysis.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.313-315
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• 2013

Hand-held devices such as smart phones exploit flash memory based storages to store data for processing jobs. Since the flash memory, non-volatile memory, is able to store mass data, it is required to use the index for processing queries. However, the flash memory has the shortcomings that it does not support the overwrite operation and its write operation is very slow. In this paper, we build the fixed grid file, one of the multi-dimensional spatial index, on a flash memory and evaluate the performance test.