• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4C
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• pp.273-281
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• 2002

Recently, demand for real-time data and multimedia data is rapidly increasing, and it is impossible for mobile Ad Hoc networks with only best effort service to efficiently transfer such data. So, we absolutely need the QoS service which reserves the communication resources in advance. The existing routing protocols, which assume that the links between nodes are bidirectional, provide the convenience for the route discovery and maintenance, but can not support the routing function for the unidirectional links due to the wireless link property easily changing with time under the real wireless environment. In order to solve such problems, in this dissertation we suggested a unidirectional QoS routing a waste of communication resources. The waste of protocol that supports unidirectional links and reduces communication resources is reduced by establishing the shortest route suitable to QoS support, considering in advance the usable communication resources at each node.

• International Journal of Computer Science & Network Security
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• v.24 no.9
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• pp.186-194
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• 2024

WebRTC (Web Real-Time Communication) is a technology that enables browser-to-browser communication. Therefore, a signalling mechanism must be negotiated to create a connection between peers. The main aim of this paper is to create and implement a WebRTC hybrid signalling mechanism named (WebNSM) for video conferencing based on the Socket.io (API) mechanism. WebNSM was designed over different topologies such as simplex, star and mesh. Therefore it offers several communications at the same time such as one-to-one (unidirectional/bidirectional), one-to-many (unidirectional) and many-to-many (bi-directional) without any downloading or installation. In this paper, WebRTC video conferencing was accomplished via LAN and WAN networks, including the evaluation of resources in WebRTC like bandwidth consumption, CPU performance, memory usage, Quality of Experience (QoE) and maximum links and RTPs calculation. This paper presents a novel signalling mechanism among different users, devices and networks to offer video conferencing using various topologies at the same time, as well as other typical features such as using the same server, determining room initiator, keeping the communication active even if the initiator or another peer leaves, etc. This scenario highlights the limitations of CPU performance, bandwidth consumption and the use of different topologies for WebRTC video conferencing.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.5
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• pp.1-9
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• 2024

With the emergence of various next-generation wireless networks, the traditional store and forward(SF) method at network nodes has faced limitations in efficiently utilizing network capacity. To overcome these limitations, various network coding techniques based on the decode and forward(DF) method have been proposed. However, these techniques have primarily focused on traffic environments with asymmetric packet lengths between relay nodes, limiting their applicability when different modulation and coding schemes(MCS) are applied to relay nodes. This paper proposes a relay network coding scheme that supports high frequency efficiency while simultaneously enabling bidirectional relaying using DF, considering asymmetric MCS traffic that reflects different transmission data and wireless channel conditions between individual nodes for efficient utilization of wireless network capacity. Additionally, this paper demonstrates the possibility of cooperative communication at the relay and examines the effect of increased communication distance. Subsequently, computer simulations are conducted to verify the performance gains of the proposed technique in terms of network coding for each source node with asymmetric information lengths. This proposed technique shows additional bit error rate(BER) performance gains by adopting an incremental redundancy(IR) scheme that follows network coding, even in mobile node environments where direct link transmission between source nodes is possible.

• Journal of Advanced Navigation Technology
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• v.21 no.5
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• pp.485-490
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• 2017

In this paper, we propose a technique for high speed removal of sea-fog using a graphic processor. This technique uses a host processor(CPU) and several graphics processors(GPU) capable of parallel processing to remove sea-fog from the input image. In the process of removing sea-fog, the dark channel extraction, the maximum brightness channel extraction, and the calculation of the transmission are performed by the host processor, and the process of refining the transmission by applying the bidirectional filter is performed in parallel through the graphic processor. To verify the proposed parallel processing method, three NVIDIA GTX 1070 GPUs were used to construct the verification environment. As a result, it takes about 140ms when implemented with one graphics processor, and 26ms when implemented using OpenMP and multiple GPGPUs. The proposed a parallel processing algorithm based on the graphics processor unit can be used for safe navigation, port control and monitoring system.

• Journal of Science of Art and Design
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• v.8
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• pp.241-266
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• 2005

Current information-oriented society is expanding rapidly with the huge change to our society from the information revolution emerged in mid '50s. Information technique such as computer, communication satellite and cable technology play their in this information-oriented society, and in 1980s, digital technique was adopted to media, inviting new phenomenon in communication of overall society. Expectations and hope for new trends and changes from digital era flourished when we entered into new Millenium, the 21st century. Since then we have gone through changes in years from analogue to digital. Now the word 'digital' is conceived in unified manner in almost every fields and influences overall society, changing our life pattern rapidly. Modern society had demanded some speedy and bidirectional communication tool in shifting digital era, and resulted from that was a new culture, Now the society changes more and more quickly under the speedy information sharing. From that perspective we need to establish the aspects of sensibility expression, which is one feature of the communication. The sensibility-oriented digital was originated from the human nature, which counts emotion and composure much. To satisfy the human nature a new cultural value which transcend a traditional one is needed. And the sensitivity expression to meet the need is one communication tendency in digital era. Digital era has totally different social qualities from that of analogue era. In digital era, prompt respond to rapid change and creativity combined with sensitivity are needed. Therefore a man with sensitivity would be more outstanding than a man of intelligence. The picture of digital and analogue in our society consists of two axis one is analogue axis like retrospective trend, admiration for nature , oriental thought etc. , and the other is the digital axis of internet and information technology. Sensibility can be widely interpreted as analogue thinking. It is surely different from the plain retrospective trend or nostalgia for past. It is a tendency that digital technology is used and cooperated with the emotion in human nature, In this paper we suggest the sensitivity expressions in detail through the study cases including both sides of digital and sensitivity expressions such as 'Bravo your life' advertising campaign of Samsung Insurance, MP3 advertising campaign, and 'Mini-homepage' of Cyworld. Under the circumstances the main direction of communication is oriented to human. This study's purpose is to think the true meaning of this digital era, to overcoming its weaknesses, such as over-dependency on technique and selfish individualism and to harmonize digital and sensitivity expression. The sensitivity-oriented expression than the reason-oriented one is expected to be put forth in whole media, and this is a more efficient tendency under the shifting digital era.

• IMMUNE NETWORK
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• v.1 no.3
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• pp.203-212
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• 2001

Background: Rapid advances in neuroendocrine immunology have established the concept of bidirectional communication between the immune and neuroendocrine systems. Capsaicin suppresses the immune function by destroying substance P acting as mediatior of neuroendocrine immune system. Methods and Results: In this study, effect of capsaicin on mature murine lymphocyte functions and lymphoid tissue morphology was examined. Formally, capsaicin showed the strong cytotoxic effect on splenocyte over $10{\mu}g/ml$ concentration in citro. And proliferation and Th1-cytokine expression of splenic cells in mice that received high dose of capsaicin ($100{\mu}g/mouse$) were significantly diminished. However, low dose of capsaicin treatment did not influence these responses in vivo($1{\mu}g/mouse$) and in vitro (under $5{\mu}g/ml$). And the morphology of spleen and lymph nodes after capsaicin treatment was observed. In the spleen of mice injected with high dose of capsaicin (100, $200{\mu}g/mouse$), the size of white pulp was significantly decreased and the length of red pulp was increased, Moreover, vascularity index was diminished in a dose dependent manner. Conclusion: These results implies that immunosuppressive effect of capsaicin is associated with cytotoxic activity on lymphocyte, Th1-cytokine down-regulation and lymphoid tissue abnormalization, and this report is expected to give a hand to the study for the mechanism of action of neurotoxin of the immune system.

• Journal of the HCI Society of Korea
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• v.2 no.1
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• pp.1-12
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• 2007

In this paper, we propose a video service system that reflects user interaction in the multimedia contents to increase user satisfaction in the restricted content consumption environment. The proposed system is based on the multiple ROI(Region of Interest) coding in H.264/AVC Scalable Video Coding (SVC). The proposed system provides scalable video quality by adopting SVC. And by bidirectional communication between user and video server, it enables user to select meaningful ROI among multiple ROIs by user interaction. To verify the usefulness of the proposed system, we demonstrate it with a test-bed on which user interactive ROIs are implemented.

• Journal of Korea Multimedia Society
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• v.2 no.2
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• pp.184-194
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• 1999

We present a new algorithm to minimize channel contention while sending multiple messages from multiple source to overlapped destination set on Multistage Interconnection Network (MIN) which supports wormhole routed turnaround routing. The multicast tree of the U-MIN(Unicast MIN) algorithm is useful in performing messages from one source to multiple destination but gives rise to a serious channel connection in performing multiple multicast because it has been designed for only single multicast. For multiple multicast communication on MIN, we address how to implement multiple multicast services efficiently. And a SPU-MIN(Source Partitioned Unicast MIN) algorithm is proposed and shown to be superior than the U-MIN algorithm for multiple multicast. The turnaround routing algorithm based on wormhole routing technique is employed as a message sending method.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.64-67
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• 1997

In the total artificial heart(TAH), a transcutaneous information transmission system(TITS) is vely important to monitor the TAH status and detect the device failure, and repair the possible problems. First of all, the communication channel(skin) and method were simulated in terms of transmittance, scattering, reflection and absorption, then the system was designed with size reduction including low power consumption and reliability compared to the previous one. The informations are transmitted through the skin(approximately 1cm in depth) by frequency modulated near infrared(NIR) pulses using 780nm laser diodes as transmitters and photodiode as receiver with high speed and high spectral sensitivity. The logic high and low frequencies are 3MHz, 1MHz respectively. The system is a bidirectional data link for more than 38.4Kbps data rate, full-duplex with a bit error rate of less than $10^{-5}$.

• Journal of Korean Academy of Nursing
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• v.37 no.2
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• pp.227-241
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• 2007

Background. Although research has established the existence of an association between smoking and depression among adolescents, researchers have not reached consensus on the nature of the association. Objectives. The purpose of this paper is to review the literature, to examine the nature of the relationship between smoking and depression in adolescence, and to suggest future research directions. Methods. A literature search was conducted from the following six databases: (a) Ovid MEDLINE, (b) CINAHL, (c) PubMed Unrestricted, (d) PsycINFO, (e) ERIC, and (f) Sociological Abstracts. The combinations of the words, "depression," "smoking," "tobacco," "adolescent," and "teen" were used for keyword searches to find relevant articles. Results. In 47 of 57 studies, significant associations between smoking and depression were found. However, these significant relationships may either be spurious or unrelated to depression because a substantial number of studies did not adjust for confounders or did not use validated instruments to measure depression. Additionally, if the relationship is causal, its direction remains controversial. Five relationships have been suggested: (a) Depression causes smoking, (b) smoking causes depression, (c) there is a bidirectional relationship between smoking and depression, (d) smoking and depression occur due to confounders, and (e) subgroups with different relationships between the two conditions exist. Conclusions. It is necessary to further explore the relationship between smoking and depression. Future research should consider the need for: (a) longitudinal research designs, (b) more accurate measurement of depression, and (c) the control of confounders between smoking and depression.