• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.2
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• pp.32-43
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• 2014

To identify major causes of the global environment changes arising from extreme and unusual weather patterns occurring these days, and to foresee future environmental changes, it is highly important to shed light on the correlation between climate changes and global environment system. To investigate the correlation between climate changes and global environment system, it calls for establishing an integrated climate-environment DB for analyzing comparatively the data on climatic changes and global environment system. In the preceding studies, we researched an XML-based integrated climate-environment DB and developed a management system for the DB. However, the existing integrated climate-environment DB, designed and installed only for individual PCs, does not allow multiple users 'simultaneous access. Accordingly, it fails to systematically update and sharing data which is being generated continuingly. Hence, this study aims to develop an easy-to-use GIS-based integrated DB management system by improving the existing integrated climate-environment DB through the adoption of the client/server model. For this, this study collected and analyzed climate and environment data prior to designing and building a DBMS-based integrated DB. In addition, in order for multidisciplinary researchers to easily get access and apply the integrated DB, this study designed and developed a GIS-based integrated DB management system using a client/server model which facilitates connections with multiple PCs. The GIS-based integrated climate-environment DB management system makes it easier to efficiently manage and locate scattered climate-environment data. It is also expected that the DB system will bring the effects in saving time and cost by avoiding the overlapping generation of data in the areas of integrated climate-environment research.

• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.582-594
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• 2004

In school PC labs or other educational purpose PC labs with a few dozens of PCs, computers are configured in a distributed architecture so that they are set up, maintained and upgraded separately. As an alternative to the distributed architecture, we can consider a thin-client computing environment. In a thin-client computing environment, client side devices provide mainly I/O functions with user friendly GUI and multimedia processing support whereas remote servers called terminal server provide computing power. In order to support many clients in the environment, a cluster of terminal servers can be configured. In this architecture, it is difficult due to the characteristics of terminal session persistence and different pattern of computing usage of users so that the utilization of terminal server resources becomes low. To overcome this disadvantage, we propose an adaptive terminal cluster where terminal servers ,ire partitioned into groups and a terminal server in a light-loaded group can be dynamically reassigned to a heavy-loaded group at run time. The proposed adaptive scheme is compared with a generic terminal service cluster and a group based non-adaptive terminal server cluster. Experimental results show the effectiveness of the proposed scheme.

• Korean Institute of Interior Design Journal
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• v.21 no.4
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• pp.12-20
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• 2012

The aim of this study is to review phenomenological characteristics in Steven Holl's architecture through his design of St. Ignatius Chapel at Seattle University. To obtain this purpose, an analytical frame based on Holl's theory of phenomenological architecture is suggested to have a systematic study for St. Ignatius chapel. This chapel can be a good example of phenomenological architecture in that it is based on the concept of 'A Gathering of Different Lights' related to phenomenology and considered perception including multi sensory (as well as vision) as primary factors from site and program interpretation to spatial configuration. Unprecedented exterior of St. Ignatius chapel reflected on characteristics and function of rooms to magnify user's spatial experiences through inducing natural light and spatial effect. Holl used various openings and screen for natural light with colors to invoke religious inspiration. He also try to give spatial depth and multi foci for experiencing space through various ceiling forms. These phenomenological features originated in client's strong will as well as appropriateness of the function of facility's religious experiences through building to the purpose of phenomenological architecture.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5B
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• pp.357-364
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• 2012

In Visible Light Communication (VLC) system, with the limitation of transmission range and Field Of View (FOV), LOS (Line of Sight) link between two transceivers should be guaranteed due to the straightness of the visible-light signal. Especially for indoor applications, link recovery is an advantage method to remain the link connection because of the link failure in which caused by movement obstacle. Link recovery schemes try to keep link dynamically without re-initialing connection. This article proposes a new link recover scheme for VLC system by using cooperative communication. Our propose scheme focuses on the QoS reservation resource by GTS in IEEE 802.15.7 specification in which the requested QoS resource from client should be guarantee during the application time. With the link recovery scheme, we will try to continue the link connection as long as possible when unexpected disconnect link. The mathematical analysis and simulation results show that proposed scheme increases the overall reliability of the VLC system.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.5
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• pp.282-296
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• 2013

With the emergence of cloud computing, more and more sensitive user data are outsourced to remote storage servers. The privacy of users' access pattern to the data should be protected to prevent un-trusted storage servers from inferring users' private information or launching stealthy attacks. Meanwhile, the privacy protection schemes should be efficient as cloud users often use thin client devices to access the data. In this paper, we propose a lightweight scheme to protect the privacy of data access pattern. Comparing with existing state-of-the-art solutions, our scheme incurs less communication and computational overhead, requires significantly less storage space at the user side, while consuming similar storage space at the server. Rigorous proofs and extensive evaluations have been conducted to show that the proposed scheme can hide the data access pattern effectively in the long run after a reasonable number of accesses have been made.

• Journal of Broadcast Engineering
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• v.22 no.4
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• pp.509-518
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• 2017

High-resolution digital holograms can be quickly generated by using a PC cluster that is based on server-client architecture and is composed of several GPU-equipped PCs. However, the data transmission time between PCs becomes a large obstacle for fast generation of video holograms because it linearly increases in proportion to the number of frames. To resolve the problem with the increase of data transmission time, this paper proposes a multi-threading-based method. Hologram generation in each client PC basically consists of three processes: acquisition of light sources, CGH operation using GPUs, and transmission of the result to the server PC. Unlike the previous method that sequentially executes the processes, the proposed method executes in parallel them by multi-threading and thus can significantly reduce the proportion of the data transmission time to the total hologram generation time. Through experiments, it was confirmed that the total generation time of a high-resolution video hologram with 150 frames can be reduced by about 30%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.2 no.6
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• pp.312-332
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• 2008

Password-based authentication key exchange (PAKE) protocols in the literature typically assume a password that is shared between a client and a server. PAKE has been applied in various environments, especially in the “client-server” applications of remotely accessed systems, such as e-banking. With the rapid developments in modern communication environments, such as ad-hoc networks and ubiquitous computing, it is customary to construct a secure peer-to-peer channel, which is quite a different paradigm from existing paradigms. In such a peer-to-peer channel, it would be much more common for users to not share a password with others. In this paper, we consider password-based authentication key exchange in the three-party setting, where two users do not share a password between themselves but only with one server. The users make a session-key by using their different passwords with the help of the server. We propose an efficient password-based authentication key exchange protocol with different passwords that achieves forward secrecy in the standard model. The protocol requires parties to only memorize human-memorable passwords; all other information that is necessary to run the protocol is made public. The protocol is also light-weighted, i.e., it requires only three rounds and four modular exponentiations per user. In fact, this amount of computation and the number of rounds are comparable to the most efficient password-based authentication key exchange protocol in the random-oracle model. The dispensation of random oracles in the protocol does not require the security of any expensive signature schemes or zero-knowlegde proofs.

• Journal of Sensor Science and Technology
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• v.16 no.2
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• pp.142-149
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• 2007

Wireless sensor network technology is an emerging technology consisting of small, low power, and low cost devices that integrate limited computation, sensing, and radio communication capabilities. An ad-hoc home network system based embedded system for home environment monitoring was fabricated and tested. The wireless sensor node consists of a MCU, RF transceiver and sensors (temperature, humidity and light). Wireless sensor nodes run application software for data sampling and wireless communication, that was developed using 'nesC language' which runs on TinyOS. In our tests, acquired sensors data were monitored on 6.4" TFT-LCD of base-station through IEEE802.15.4 standard wireless communication. Also, the sensor data can be monitored by client user at the terminal PC to monitor environmental status of home in real time.

• The KIPS Transactions:PartA
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• v.11A no.1
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• pp.57-66
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• 2004

According to the development of home-network, home-network middleware supporting interoperability between devices connecting to home-network has been variously Proposed. As a typical middleware, UPnP and Jini are developed individually. So, to extend the usage of home-network, it is necessary to have connections among various home-network middleware. In this paper, we study about home-network middleware UPnP and Jini, and design and implement UPnP-to-Jini service which allows Jini client to use UPnP device using the speciality of UPnP performance process. Using application of light on-off we implemented the connection of them.

• Science of Emotion and Sensibility
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• v.23 no.1
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• pp.57-68
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• 2020

This research investigates how digital design agencies and client companies incorporate design thinking-a human-centered approach to solving difficult problems-into their website development processes. Based on a literature review on the design-thinking-driven web development process, multiple case studies of award-winning website projects were performed by in-depth interviews with key practitioners. Through analyses of these cases, their user-centered approaches for website innovation were identified according to the following four phases: web planning (discovery and defining phases) and web design and development (development and delivery phases). Moreover, distinct approaches of design thinking practices were identified according to two website types: a brand promotion website with a killer brand storytelling approach; and a service channel website with a strategic UI/UX-driven approach. Next, the key success drivers of these website projects were suggested in light of the typical themes of design thinking (i.e., human centeredness, research based, context awareness, and collaboration). Some practical limitations were also found in adopting the design-thinking-driven web development process, such as limited research methods and tools, and insufficient prototyping and experimentation. Along with these limitations, it was also discovered that current digital design agencies still face the following challenges in adopting the design-thinking-driven web development process: building a long-term, playful partnership with clients; leveraging decision-makers' design thinking awareness; and coping with limited resources (design thinking practitioners, budgets, and schedules).