• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.4717-4737
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• 2017

Today, smart grids, smart homes, smart water networks, and intelligent transportation, are infrastructure systems that connect our world more than we ever thought possible and are associated with a single concept, the Internet of Things (IoT). The number of devices connected to the IoT and hence the number of traffic flow increases continuously, as well as the emergence of new applications. Although cutting-edge hardware technology can be employed to achieve a fast implementation to handle this huge data streams, there will always be a limit on size of traffic supported by a given architecture. However, recent cloud-based big data technologies fortunately offer an ideal environment to handle this issue. Moreover, the ever-increasing high volume of traffic created on demand presents great challenges for flow management. As a solution, flow aggregation decreases the number of flows needed to be processed by the network. The previous works in the literature prove that most of aggregation strategies designed for smart grids aim at optimizing system operation performance. They consider a common identifier to aggregate traffic on each device, having its independent static aggregation policy. In this paper, we propose a dynamic approach to aggregate flows based on traffic characteristics and device preferences. Our algorithm runs on a big data platform to provide an end-to-end network visibility of flows, which performs high-speed and high-volume computations to identify the clusters of similar flows and aggregate massive number of mice flows into a few meta-flows. Compared with existing solutions, our approach dynamically aggregates large number of such small flows into fewer flows, based on traffic characteristics and access node preferences. Using this approach, we alleviate the problem of processing a large amount of micro flows, and also significantly improve the accuracy of meeting the access node QoS demands. We conducted experiments, using a dataset of up to 100,000 flows, and studied the performance of our algorithm analytically. The experimental results are presented to show the promising effectiveness and scalability of our proposed approach.

• Journal of the Korean Chemical Society
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• v.46 no.6
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• pp.495-501
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• 2002

The critical micelle concentration(CMC) and the counterion binding constant(B) for the mixed micel-lization of sodium n-octanoate(SOC) with n-octylammonium chloride(OAC) were determined as a function of the overall mole fraction of $SOC({\alpha}_1).$ Various thermodynamic parameters($x_i$, $Y_i$, $C_i$, $${\alpha}_i^M$$, and $\Delta$$H_{mix}$) for the mixed micellization of the SOC/OAC systems have been calculated and analyzed by means of the equations derived from the nonideal mixed micellar model. The results show that there are great deviations from the ideal behavior for the mixed micellization of these systems. And other thermodynamic parameters(${\Delta}$$G^0_m$, ${\Delta}$$H^0_m$, and ${\Delta}$$S^0_m$) associated with the micellization of SOC,OAC, and their $mixture({\alpha}_1=0.5)$ have been also estimated from the temperature dependence of CMC and B values, and the significance of these parameters and their relation to the theory of the micelle formation have been considered and analyzed by comparing each other.

• Journal of Korean Society of Transportation
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• v.20 no.3
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• pp.129-147
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• 2002

This paper presents a variational equality formulation by Providing new dynamic route choice condition for a link-based dynamic traffic assignment model. The concepts of used paths, used links, used departure times are employed to derive a new link-based dynamic route choice condition. The route choice condition is formulated as a time-dependent variational equality problem and necessity and sufficiency conditions are provided to prove equivalence of the variational equality model. A solution algorithm is proposed based on physical network approach and diagonalization technique. An asymmetric network computational study shows that ideal dynamic-user optimal route condition is satisfied when the length of each time interval is shortened. The I-394 corridor study shows that more than 93% of computational speed improved compared to conventional variational inequality approach, and furthermore as the larger network size, the more computational performance can be expected. This paper concludes that the variational equality could be a promising approach for real-time application of a dynamic traffic assignment model based on fast computational performance.

• Journal of Advanced Navigation Technology
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• v.6 no.1
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• pp.44-51
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• 2002

This paper describes the performance evaluation and analysis of an Orthogonal Frequency-Division Multiplexing (OFDM) system having the least Inter Symbol Interference (ISI) in a multi-path fading channel environment. Wireless Local Area Network (W-LAN) in accordance with IEEE 802.11a and IEEE 802.11b provides high-speed transmission to universities, businesses and other various places. In addition, service providers can offer a public W-LAN service on restricted areas such as a subway. The proliferation of W-LAN has led to greater W-LAN service demands, but problems are also on the rise in offering a good W-LAN service. In particular, urban areas with high radio wave interference and many buildings are vulnerable to deteriorated QoS including disconnected data and errors. For example, when high-speed data is transmitted in such areas, the relatively high frequency generates ISI between Access Points (AP) and Mobile Terminals (such as a notebook computer), leading to a frequency selective fading channel environment. Consequently, it is difficult to expect a goodW-LAN service. The simulation proves that the OFDM system enables W-LAN to implement QoS in high-speed data transmission in a multi-path fading channel environment. The enhanced OFDM performance with 52 sub-carriers is verified via data modulation methods such as BPSK, QPSK and 16QAM based on IEEE 802.11a and punched convolutional codes with code rate of 1/2 and 3/4 and constraint length of 7. Especially, the simulation finds that the OFDM system has better performance and there is no data disconnection even in a mobile environment by applying a single tap equalizer and a decision feedback equalizer to a mobile channel environment with heavy fading influence. Given the above result, the OFDM system is an ideal solution to guarantee QoS of the W-LAN service in a high-speed mobile environment.

• Journal of Advanced Navigation Technology
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• v.6 no.1
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• pp.37-43
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• 2002

This paper describes the performance evaluation and analysis of Wireless Local Area Network (W-LAN) in the 5 GHz ISM-band in compliance with IEEE 802.11a. At present, most W-LAN products are based on 2.4 GHz band, but low speed (11Mbps) has the limitation to serve systems demanding high-speed data transmission. To solve this problem, it is necessary to design next generation W-LAN system with 54Mbps in the 5GHz. It is sure that implementation of next generation W-LAN will bring competitive advantages. In particular, it will support telecommunications for high-speed mobile environments as well as for fixed places such as a school zone, a lecture room, a hospital and other premises. A few simulation methods are applied to more accurate and reliable performance analysis of next generation W-LAN. To verify if continuous data service is supported for a high-speed mobile notebook, multi-path fading channels between wireless Access Point (AP) and wireless Network Interface Card (NIC) are modeled. In addition, low interference is analyzed via convolutional codes and Orthogonal Frequency-Division Multiplexing (OFDM). Also, to obtain reliable Bit Error Rate (BER), a single tap Least Mean Square (LMS) equalizer is applied. Given the above simulation, next generation W-LAN is an ideal solution for continuous data transmission in high-speed mobile environments.

• Sijohaknonchong
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• v.26
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• pp.55-75
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• 2007

Sijo is the essence of Korean literature and the most ideal poetic form through which we can express our images gracefully in three lines. Hence it deserves special emphasis either in creative writing and appreciating it from elementary school to middle school. In this paper observes how Sijo is taught in the schools and suggests the direction of educating Sijo. There may be three kinds of Sijo performance, namely, recitation, reading, and singing. In this paper. it is claimed that the performance of Sijo in the twenty first century should be recitation. Sijo education may be effective when it focuses on a way of recitation in which, with natural and long breath, a piece of Sijo is recited at length. Nevertheless, it is not practiced as the way of recitation because of following two reasons. Firstly. the analysis on rhythm, which is on the base of its recitation, is extremely difficult. Secondly, the theoretical ways, which is obsolete and lacks vividness, are ineffective in education. By these reasons. 1 studied how to give a recitation following my preceding studies on rhythm and rhythmical reading of Sijo. As a result, this paper suggests a reading method as a solution to the problems. In fact, we Korean can discipline our mind and body through reciting Sijo to the rhythm which is transcendental to Korean and at the same time, Sijo education helps to enhance our pride as koreans in the process of studying Sijo.

• Korean journal of communication and information
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• v.37
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• pp.7-42
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• 2007

There has been growing debate over the current crisis of Korean journalism especially since 1997. While identifying primary causes as 'lack of credibility and public accountability,' however, this paper claims that self-regulation initiated by enlightened and professionalized journalists is a plausible solution. This paper thus pays attention to U.S. graduate journalism schools which provide specialized program about business/economic/financial news. For this, in identifying commonalities of the programs in terms of education goals, geographical/academic resources and course works, this study wanted to elicit meaningful implications for media education. It was suggested in conclusion that not only would Seoul be an ideal place for combining theoretical and practical training, but such programs in New York and Columbia university might be creatively applied to Korean journalism school. Finally, the author hopes that this review will be a good starting point for envisioning graduate level of journalism school in Korea.

• Management & Information Systems Review
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• v.35 no.3
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• pp.173-193
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• 2016

The aim of this paper is to extend the TOPSIS(Technique for Order Preference by Similarity to Ideal Solution) to the fuzzy environment for solving the disaster recovery priority decision problem in credit bureau business information system. In this paper, the rating of each information systems and the weight of each criterion are described by linguistic terms which can be expressed in trapezoidal fuzzy numbers. Then, a vertex method is proposed to calculate the distance between two trapezoidal fuzzy numbers. According to the concept of the TOPSIS, a closeness coefficient is defined to determine the ranking order of all information systems. The combination between the fuzzy set and TOPSIS brings several benefits when compared with other approaches, such that the fuzzy TOPSIS require few fuzzy judgements to parameterization, which contributes to the agility of the decision process, it does not limit the number of alternatives simultaneously evaluated, and it does not cause the ranking reversal problem when a new alternative is included in the evaluation process. This paper is demonstrated with a real case study of a credit rating agency involving 9 evaluation criteria and 9 credit bureau business information systems assessed by 6 evaluators, and provide the systematic disaster recovery framework for BCP(Business Continuity Planning) to practitioner. Finally, this paper show that the procedure of the proposed fuzzy TOPSIS method is well suited as a decision-making tool for the disaster recovery priority decision problem in credit bureau business information system.

• Research in Community and Public Health Nursing
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• v.12 no.2
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• pp.361-374
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• 2001

This study was done to identify a status of home visiting project as a community health nursing system, that was the organization. personal who have age, educational background, marital status, position, experience of the home visiting in the public sectors in part of Seoul. Kyonggi, Kang-won area, It was done to provide basis data for the development of effective visiting nurses project in the health sectors, where was Health Centers in urban and rural. Branch of Health Center in rural and Health posts. The question airs were distributed 352 public health workers who working place was 118 health workers in 12 health centers in Seoul. 56 public health workers among 39 health center and other public health sectors in Kyonggi and 178 public health workers among health center and health care sectors. Data collected from October to December. 2000. The analysis by SAS system with F test, percentage and frequency. The major result were as follows. The general characteristics of the respondent show that most of them were graduates from community college and RN-BS with broadcast that they had not completed CPHN course but only two health workers have trained for the visiting nurses project. As for their grade in the position, the most of health workers have seventh level and the other CHP were above sixth level in the health care post that in the government structure. This indicates that workers do not have great authority in decision making, the most period of works in the position was one and two years indicating that they change jobs frequently. On an average their clinical experience was 4.11 years which is ideal for the total service. As for preparation of staff for home visiting workers education on visiting nurses program have to receive short term or longer term training course for strong emphasis. The analysis showed that public health visiting workers responds about active job performance that based on an area, approach of acting by districts, education and position are shown statistically significant difference between acceptance of the visiting nursing job show the same as well as visiting nurses project. Special concerns for visiting Nursing care spread came to burden, many of activity carry out main solution is covered the health problem connective support system needs of quality and quantity which out health problem. As 71.1% of visiting health service held on the poor population was under the guardianship of the law, but people who health insurance wide application under law shown a tendency to increase gradually. The general characteristics of the patients showed 56.2% of female on average of age was 66.1 years old, they have health problem was the most of 47.6% of high blood pressure and stroke, the other and as a problem that economics, which is complex welfare with out health problem. Community health care service should be combined health and social work program. The form of delivery of visiting health care given the most guide and education with counselling and support. (33.6%) Among the six category of visiting care service shown statistically significant difference and next is fundamental care, remedy care with priority.

• Korean Chemical Engineering Research
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• v.52 no.2
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• pp.214-218
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• 2014

In this study, nanoporous $Cu_3(BTC)_2$ membranes were synthesized on macroporous alumina tube supports by solvothermal method. It is very difficult to prepare uniform and crack-free $Cu_3(BTC)_2$ layer on macroporous alumina support by in situ solvothermal method. In this study, continuous and crack-free $Cu_3(BTC)_2$ tubular membranes could be obtained by in situ solvothermal process after surface modification of alumina support. The surface modification was conducted by spraying Cu precursor solution on the alumina support heated at $200^{\circ}C$. The prepared $Cu_3(BTC)_2$ tubular membranes were characterized by XRD, FE-SEM and gas permeation experiments. $H_2$ permeance through $5{\mu}m$ thick $Cu_3(BTC)_2$ tubular membrane was calculated to be $7.8{\times}10^{-7}mol/s{\cdot}m^2{\cdot}Pa$ by single gas permeation test, with the ideal selectivities of $H_2/N_2=11.94$, and $H_2/CO_2=12.82$.