• Journal of Internet Computing and Services
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• v.11 no.1
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• pp.35-48
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• 2010

For the next generation mobile communication system, diverse wireless network techniques such as beyond 3G LTE, WiMAX/WiBro, and next generation WLAN etc. are proceeding to the form integrated into the All-IP core network. According to this development, Beyond 3G integrated into heterogeneous wireless access technologies must support the vertical handover and network to be used of several radio networks. However, unified management of each network is demanded since it is individually serviced. Therefore, in order to solve this problem this study is introducing the theory of Common Radio Resource Management (CRRM) based on Generic Link Layer (GLL). This study designs the structure and functions to support the vertical handover and propose the vertical handover algorithm of which policy-based and MCDM are composed between LTE and WLAN systems using GLL and CRRM. Finally, simulation results are presented to show the improved performance over the data throughput, handover success rate and the system service cost.

• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.85-98
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• 2009

Recently, there are a number of researches and developments for the personalized software platform for mobility based on SaaS. The platform requires an optimal virtual machine in order to satisfy the operating systems of various users for the software. In addition, the platform must guarantee the mobility of the users' working environments by supporting fast and secure services between internal and external networks in the platform operating systems. In order to verify the optimal behaviors of virtual machines for the platform, the performance of the virtual machines must be measured and analyzed in various perspectives. In the previous research, unfortunately, the performance of a virtual machine were conducted in the condition that a guest operating system was installed on the virtual machine and considered as a computer, by measuring the network traffic between the guest operating system and an external client operating system. This performance measurement was not suitable for a virtual machine for the platform since a number of different software must be handled in the virtual machine. In order to overcome this limitation, this paper presents a measurement method for network performance and proposes the most optimal virtual machine by the method.

• Korean Journal of Ecology and Environment
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• v.49 no.4
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• pp.258-270
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• 2016

This study was conducted to test the green-tide mitigation technique in the lower part of the Sook Stream (Chusori) of Daecheong Reservoir from June 27 to August 24, 2014. And the effects were compared with weekly monitoring result of the watching station of the algae alert system (AAS) as well as test beds reach. The green-tide in a test bed was begun from the upstream, and it was gradually transferred and spread toward the downstream by the hydrological factors. The total amount of algae removed by algae removal device during the test period was 33,920 kg, and solids dewatered by natural gravity was 8,480 kg. Also chlorophyll-a content was 2.83 kg, the number of blue-green algae cells was equivalent to $78.6{\times}10^{14}$ cells. Compared with the results of the watching station of AAS, the pre-concentrate removal work in the outbreak waters was able to suggest the possibility of green-tide mitigation. In addition, an effective management of the green-tide was required spatial and temporal occurrence information and practical device technology. Particularly, the optimal timing of algae removal in the river-reservoir hybrid system was recommended at times before the monsoon rainy season and reached the lowest water level.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.55-59
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• 2010

Currently in a Ubiquitous Sensor Network (USN) research field, supporting mobility is recognized as an important technology. MIPv6 and Network Mobility(NEMO) Basic Support Protocol are standard protocols to support mobility in the Internet. However, if they are applied to USN with no modification, handoff performance decreases due to the size of their binding message. An existing lightweight protocol for NEMO protocol has a compatibility problem of Sequence Num. and does not optimally compress binding messages considering 6LoWPAN network structure and addressing. This paper proposes optimal header compression which supports node-based mobility and network-based mobility. Our optimal compression technique compresses a 32bytes binding update(BU) message and a 12bytes binding ACK(BA) message of MIPv6 into 13bytes and 3bytes, and a 40bytes BU message and a 12bytes BA message of NEMO protocol into 13bytes and 3bytes. The result shows that our protocol compresses 15bytes (NEMO-BU) and 1byte (NEMO-BA) more than the existing protocol and achieves 8.72% handoff performance improvement.

• Journal of KIISE:Software and Applications
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• v.33 no.6
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• pp.580-587
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• 2006

As PDA, IMT-2000, and e-Book are developed and popular in these days, the number of users who use these products has been increasing. However, available memory size of these machines is still smaller than that of desktop PCs. In these products, TrueType fonts have been increased in demand because the number of users who want to use good quality fonts has increased, and TrueType fonts are of great use in Windows CE products. However, TrueType fonts take a large portion of available device memory, considering the small memory sizes of mobile devices. Therefore, it is required to reduce the size of TrueType fonts. In this paper, two-phase compression techniques are presented for the purpose of reducing the sire of hangul bitmap data embedded in TrueType fonts. In the first step, each character in bitmap is divided into initial consonant, medial vowel, and final consonant, respectively, then the character is recomposed into the composite bitmap. In the second phase, if any two consonants or vowels are determined to be the same, one of them is removed. The TrueType embedded bitmaps in Hangeul Wanseong (pre-composed) and Hangul Johab (pre-combined) are used in compression. By using our compression techniques, the compression rates of embedded bitmap data for TrueType fonts can be reduced around 35% in Wanseong font, and 7% in Johab font. Consequently, the compression rate of total TrueType Wanseong font is about 9.26%.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.11
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• pp.393-402
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• 2014

We have experienced an explosive increase of the IoT(Internet of Things) technology based devices including smart phones and the wireless communications. Also the growing power consumption in IEEE 802.11 WLANs(Wireless LANs) driven by these dramatic increases in not only mobile users and but also wireless APs(Access Points). To reduce the power consumption, this paper proposes a wireless AP power saving algorithm, which minimizes the transmission power without decrease the transmission and carrier sense ranges. A wireless AP which is use in our algorithm checks its own original coverage periodically for whether there is a new STA(Station) or not when its transmission power is decreased. Moreover, if there are no signaling message to connect the wireless AP, it changes its operation mode Wake-up to sleep. A Result shows that the proposed AP algorithm can reduce the total power consumption of the wireless AP approximated 18% and 35% compared to the conventional wireless AP with and without the existing power saving algorithm, respectively.

• Journal of Legislation Research
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• no.53
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• pp.213-267
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• 2017

Regulatory barrier is considered most challenging out of all FinTech barriers, which many technology innovators have always experienced. Even though technological solutions promise customers accessibility to more cost-effective and secured financial services, it is quite challenging to create regulatory environment that enables innovation FinTech industry. Especially, a common challenge FinTech innovators and business face is regulatory uncertainty and confusion rather than any particular regulation. Since many FinTech models are continuously introducing new innovative ways in providing financial services, significant confusion could be raised in applying principles of existing law and regulations. In addition, it is uncertain whether or not applying complex regulatory compliance model intended for large financial institutions to small start-ups is appropriate since most existing regulations and rules are established and introduced without considering innovative tools such as mobile instruments, e-trade, and internet. Therefore, new mechanism to access to regulatory information in a more cost-effective, quick and immediate way should be created. Regulators, technological innovators, and financial customers should cooperate each other to find out appropriate solutions for those issues. Many regulators are introducing regulatory sandbox which provides service providers with opportunities to test their innovations, during the test, providing regulators with enough time to understand risks of innovations. However, regulatory sandbox is not a panacea for all challenges to FinTech innovations. Therefore, regulators should make comprehensive and multidimensional efforts including regulatory sandbox in supporting FinTech ecosystem.

• Journal of the Korea Convergence Society
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• v.10 no.11
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• pp.289-296
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• 2019

In the era of M-ICT (mobile information communication technology), it is becoming more and more important to establish a city brand image that is "user-centered" and creates a new experience of "interaction between people, people and things, and people and space". The experience of city users on the brand image of a city is the key factor to determine the competitiveness of the city, among which the user's research on the touch point of the city brand is particularly important. The purpose of this study is to enhance the user's brand experience and enhance the city's brand competitiveness. The research methods of this paper are literature review and investigation. Firstly, the background and purpose of the study are expounded, then the characteristics and ways of user experience touch points are defined through the document review, and the multi-latitude composition model of city brand touch points is proposed. By means of user investigation, the structural characteristics of high frequency touch points between digital touch points and physical touch points are obtained. According to the problems found in the investigation, the optimal design strategy of touch point is put forward in combination with the case. The innovation of this study is to study the relationship between the city brand and the touch point of user experience from the perspective of user experience, and propose a multi-latitude model of the touch point of city brand.

• Journal of Conservation Science
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• v.37 no.5
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• pp.440-450
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• 2021

Temperature and humidity data collection using real-time sensors and data loggers was conducted for integrated pest management in the collection storage and exhibition space of the Jeongnimsaji Museum, Buyeo. The real-time temperature and humidity monitoring system collected measurement data every 30 minutes and enabled real-time confirmation of the data through a linked application. If the temperature and humidity data measured in the real-time temperature and humidity monitoring system exceeds the set range, a push notification was sent to the mobile phone of the person in charge to provide status information to establish a continuous management system. Through this, it was possible to immediately recognize and take action when the temperature range exceeded the recommended relic temperature in August. We performed data visualization on the concentration of airborne fungus in the storage area and the inflow path and density of insects. Based on the recommended criteria presented by the National Institute of Cultural Heritage, The data on the spatial and temporal concentration of airborne fungus inside the collection storage were found to be maintained at a value below the standard recommended by the National Institute of Cultural Heritage (80 CFU/m³). Also, as a result of the insect inflow survey, no insects were captured inside the storage area, and in the case of the exhibition space, insects such as Scutigera coleoptrata, Loxoblemmus arietulus, Diestrammena asynamora, Koreoniscus racovitzai were captured. Based on this, as a result of visualization according to the individual density of captured insects by area, it was confirmed that the main inflow paths of insects were the external entrance and the toilet area.

• Knowledge Management Research
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• v.22 no.3
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• pp.253-271
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• 2021

Due to the spread of COVID-19, the use of O2O order·delivery applications are becoming very common. Unlike the past, where customers could choose the desired transaction method and channel, these days, where customers' choices are very limited, it is urgent to consider the concept of shadow labor which has been hindered by the convenience and the benefits of order·delivery app. To this end, in this study, the service quality factors perceived by users of O2O order·delivery app and their shadow work attributes were identified, and priorities according to their relative importance and satisfaction level were suggested. In order to fulfill research objectives, first, after collecting user reviews for an O2O order·delivery app, the subject words were derived using topic modeling. Research variables were selected by linking 11 keywords with the concepts of previous studies on service quality of mobile apps and those about shadow labor. Eight variables of usefulness, ease of use, stability, design quality, personalization, responsiveness, update, and presence were selected. Based on 32 measurement items from the variables, a revised IPA was conducted, and finally, 'keep', 'concentrate', 'low priority', or 'overkill' service quality factors are revealed.