• Journal of Internet Computing and Services
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• v.8 no.5
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• pp.133-140
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• 2007

Currently, as the requirement for high quality Internet access from anywhere at anytime is consistently increasing, the interconnection of pure ad hoc networks to fixed IP networks becomes increasingly important. Such integrated network, referred to as hybrid ad hoc networks, can be extended to many applications, including Sensor Networks, Home Networks, Telematics, and so on. We focus on some data communication problems of hybrid ad hoc networks, such as broadcasting and routing. In particular. power failure of mobile terminals is the most important factor since it affects the overall network lifetime. We propose an energy-efficient routing protocol based on clustering for hybrid ad hoc networks. By applying the index-based data broadcasting and selective tuning methods, the infra system performs the major operations related to clustering and routing on behalf of ad hoc nodes. The proposed scheme reduces power consumption as well as the cost of path discovery and maintenance, and the delay required to configure the route.

• Journal of Korea Society of Industrial Information Systems
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• v.11 no.4
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• pp.32-39
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• 2006

MANET is a dynamically reconfigurable wireless network with no fixed infrastructure (base station, or AP). In order to provide the data service in MANET, we need an efficient routing protocol to deliver the data to the wanted destination at a mobile node. A method of routing protocols called reactive routing protocol has recently got attention because of their low routing overhead. But a method of flooding broadcasts the packet to all of its neighbors. For this reason, each of the node has high routing overhead to route and keep path discovery. Accordingly in this paper, I propose an adaptive flooding scheme using N-hop look-ahead in MANET, md an optimal N value of doing flooding the packet to limited area. Because of being basically ignorant about topological changes, each of the node did not spontaneously cope with path alteration. But an efficient flooding scheme applying N-hop look-ahead is more resilient to topology changes than traditional algorithms. And also with this efficient flooding scheme, the simulation results demonstrate excellent reduction of routing overhead.

• The KIPS Transactions:PartC
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• v.12C no.5 s.101
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• pp.617-622
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• 2005

Lately, the MANET research has focused on providing routing services with security and previous schemes have been proposed for detecting malicious nodes in a MANET. However, they still include some problems which malicious nodes cannot be found when they falsely report other nodes as malicious. Accordingly, we propose a novel and efficient scheme for detecting malicious nodes using report messages and a report table which is consisted of node ID both for suspecting and reporting when the malicious nodes behave normally during the route discovery, but the other hand they drop and modify packets, or falsely report other nodes as malicious during the data transmission. Our proposed scheme is applicable to not only DSR but aiso AODV. And we provide some simulation results of our proposed scheme by comparing general AODV with our proposed scheme. Simulation results show that our Proposed scheme outperforms general AODV in terms of average packet loss ratio and packet delivery ratio.

• YAKHAK HOEJI
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• v.54 no.6
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• pp.494-499
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• 2010

We have been focussing on discovery of natural compounds that have immunoregulatory activities for many years. In the present study, we investigated if chlorogenic acid (CRA), a polyphenolic compound, has an immunoadjuvant activity. Prior to examining the immunoadjuvant activity, effect of CRA on proliferation of T- or B-lymphocyte was determined. Results showed that CRA enhanced the proliferation of those lymphocytes in dose-dependant manner (P<0.05), and the proliferation enhancement by CRA was appeared to be more effective to B-cells than to T-cells. Based on these observations, it was tested with bovine serum albumin (BSA) and Candida albicans cell wall (CACW) as antigenic sources if CRA has an immunoadjuvant activity. In experiments, BSA alone or a mixture of BSA plus CRA was injected intraperitoneally to mice (BALB/c strain). For a negative control, mice were given only diluent (DPBS) by the same route. In other experiment, CACW was tested by the same way as did with BSA. Three weeks after the first immunization these animals were boosted. Antisera collected from the mice one week after the booster were analyzed by ELISA. Results displayed that the induction of anti-BSA antibody was increased in mice that received the mixture of BSA and CRA as compared to anti-BSA induction in BSA only-given mice groups (P<0.05). In case of CACW, a similar observation as did with BSA was made, resulting in that there was app. 40% increased production of the anti-CACW antiserum from the combination (CACW plus CRA)-received mice as compared to antiserum induction from CACW alone-given animals. Taken all together, these data indicate that CRA has an ability of enhancing antibody production regardless of nature of antigenic sources. Presumably, activation of B-cell proliferation by CRA may plays an important role in the immunoadjuvant activity of the polyphenolic compound.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.2
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• pp.147-150
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• 2020

Relatively pure YBCO was first synthesized by heating a mixture of metal carbonates at temperatures between 1,000 and 1,300 K, resulting in the reaction: 4BaCO₃+Y₂(CO₃)₃+6CuCO₃+(1/2_-x)O₂ → 2YBa₂Cu₃O_7-x+1/3CO₂. Modern syntheses of YBCO use the corresponding oxides and nitrates. The superconducting properties of YBa₂Cu₃O_7-x are sensitive to the value of x, i.e., its oxygen content. Only those materials with 0≤x≤0.65 are superconducting below Tc, and when x ~ 0.07, the material superconducts at the highest temperature, i.e., 95 K, or in the highest magnetic fields, i.e., 120 T and 250 T when B is perpendicular and parallel to the CuO₂ planes, respectively. In addition to being sensitive to the stoichiometry of oxygen, the properties of YBCO are influenced by the crystallization methods applied. YBCO is a crystalline material, and the best superconductive properties are obtained when crystal grain boundaries are aligned by careful control of annealing and quenching temperature rates. However, these alternative methods still require careful sintering to produce a quality product. New possibilities have arisen since the discovery of trifluoroacetic acid, a source of fluorine that prevents the formation of undesired barium carbonate (BaCO₃). This route lowers the temperature necessary to obtain the correct phase at around 700℃. This, together with the lack of dependence on vacuum, makes this method a very promising way to achieve a scalable YBCO bulk.

• Biomolecules & Therapeutics
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• v.28 no.4
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• pp.344-353
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• 2020

This study aims to develop new potential therapeutic moracin M prodrugs acting on lung inflammatory disorders. Potential moracin M prodrugs (KW01-KW07) were chemically synthesized to obtain potent orally active derivatives, and their pharmacological activities against lung inflammation were, for the first time, examined in vivo using lipopolysaccharide (LPS)-induced acute lung injury model. In addition, the metabolism of KW02 was also investigated using microsomal stability test and pharmacokinetic study in rats. When orally administered, some of these compounds (30 mg/kg) showed higher inhibitory action against LPS-induced lung inflammation in mice compared to moracin M. Of them, 2-(3,5-bis((dimethylcarbamoyl)oxy)phenyl)benzofuran-6-yl acetate (KW02) showed potent and dose-dependent inhibitory effect on the same animal model of lung inflammation at 1, 3, and 10 mg/kg. This compound at 10 mg/kg also significantly reduced IL-1β concentration in the bronchoalveolar lavage fluid of the inflamed-lungs. KW02 was rapidly metabolized to 5-(6-hydroxybenzofuran-2-yl)-1,3-phenylene bis(dimethylcarbamate) (KW06) and moracin M when it was incubated with rat serum and liver microsome as expected. When KW02 was administered to rats via intravenous or oral route, KW06 was detected in the serum as a metabolite. Thus, it is concluded that KW02 has potent inhibitory action against LPS-induced lung inflammation. It could behave as a potential prodrug of moracin M to effectively treat lung inflammatory disorders.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1284-1294
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• 2010

The ZigBee is one of the most important technologies for composing USN. It is one of the IEEE 802.15.4 standards to support personal area networks. It uses a hierarchical routing or an on-demand route discovery strategy as an address allocation method. A hierarchical routing doesn't use a routing table but only uses a child node or a parent node as an intermediate node for data delivery. Therefore, the ZigBee network's topology greatly affects the overall network performance. In this paper, we propose a more trustworthy algorithm than only using the depth and widely variable LQI during network formation, and moreover we propose an algorithm to measure network's trustworthiness. We simulate our algorithm using the NS-2 and implement our network using the MG2400 ZigBee module for verifying performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.9
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• pp.1665-1671
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• 2007

Mobile Ad hoc Networks (MANETs) refer to autonomous networks in which wireless data communications are established between multiple nodes in a given coverage area without a base station or centralized administration. Because of node mobility and limited battery life, the network topology may changes frequently. Selecting the most reliable path during route discovery process is important to improve performance in ad-hoc networks. In this study, we proposed an enhanced routing protocol based on AODV by monitoring variation of receiving signal strength. New metric function that consists of node mobility and hops of path is used for routing decision. From extensive experiments by using NS-2, The performance of the proposed routing scheme has been imp개ved by comparison to AODV protocol.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.11
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• pp.730-742
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• 2014

In the case of On-demand routing protocol in cognitive radio ad-hoc networks, broadcasting of control packets may occur common control channel overload and packet collisions during the routing procedure. This situation is to increase the overhead of path finding and also limited to find the accurate and reliable path. Since reliable channel and path finding is restricted, path life time is shorten and path reliability is reduced. In this paper, we propose a new routing algorithm that reduces control channel overhead and increases path life time by considering the probability of appearance of primary user and channel status of neighbor nodes. Each node performs periodic local sensing to detect primary user signal and to derive primary user activity patterns. The probability of primary appearance on the current channel and the channel status can be obtained based on the periodic sensing. In addition, each node identifies the quality of the channel by message exchange through a common channel with neighbor nodes, then determines Link_Levels with neighbor nodes. In the proposed method, the Link Level condition reduces the number of control messages that are generated during the route discovery process. The proposed method can improve path life time by choosing a path through Path_Reliability in which stability and quality are weighted depending on the location. Through simulation, we show that our proposed algorithm reduces packet collisions and increases path life time in comparison with the traditional algorithm.

• The Research Journal of the Costume Culture
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• v.8 no.3
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• pp.387-410
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• 2000

The purpose of this study was to approach to the internal meanings included in the Happening and the culture of hippies, by analysing the basic mental conditions in the process of the Happening. And this study was composed of the concept and the development of Happening, the characteristics of the hippies that related in the midst of the happening's background, and the formativeness between these factors and hippies'fashion. Since the happening a genre of fine arts expression attended the New School for social research in New York in 1954, Allan Kaprow direct-influenced by John Cage used the word 'Hapening'first, practicing '18 Happenings in 6 parts'at the Rueben gallery in 1959. Kaprow's 18 Happenings was one of the earliest opportunities for a wider public to attend the live events that several artists had performed more privately for various friends. Despite the very different sensibilities and structures of artist's works, artists were all thrown together by the press under the general heading of 'Happening', following Kaprow's 18 Happenings. Being considered as the root of the Happening 'Expression of Sound'of John Cage was the discovery of the exisiting thing- the Happening. Most artists were to be deeply influenced by Cage's theories and attitudes-that is, his sympathy for Zen Buddihism and oriental philosophy-and by reports of the Black Mountain events. These events would directly reflect contemporary painting and stemmed from the Futurists, Dadaists and Surrealists. And Happening's development background was based on the culture of hippies. Swinging London had been under the sway of psychedelic drugs and utopian visions of 'hippie'wave sweeping in from Califonia. This wave, which affected solid middle-class youth first and formost, began in Haight Ashbury in San Francisco. Without dwelling on the hippie movement here, it is worth nothing that it resulted from the convergence of several undercurrents : consciousness-expending drugs, the anti-Vietnam war developments, the impact of English pop groups on American music and the rise of protest songs, and finally the beatnik tradition of non-conformism. Hippie culture and its pursuit of love, peace and psychedelia was the antitheses of 1960s main street fashion. The media gave everyone with long hair the label of 'hippie', but it was always a very loose collage of attitudes and styles. The rejection of sexual taboos was conveyed by the hippie's refusal to wear. Although the bold exposure of body raised controversies because it went against the existing moral values, it has a significant implications. Psychedelics brought mind-expansion and the possibillity that modern technology (light show, synthesized electronic sounds), new fabrics or colors, and LSD could be utilized to provide an escape route from the dreariness of modern life. During the 1960s, traditional costumes, many of which had never been seen outside their native regions, became sought after and adopted in the West, initially by the young, who wanted to demonstrate their solidarity with cultures uncontaminated by mass industry. The most ardent proponents of such folk costumes were the hippies. Hippies dress was sometimes decribed as 'anti-fashion', produced by a patchwork of ragged cast-offs and flamboyant accessories, of outmoded Western dress and time-honored ethnic garments all combined, modified and permutated into variety of personal statements. 'Flower Power'became a reality. From the results of this study, we can see the expanding trend of the influence and the concept of the sew art genre 'Happening'in the formativeness as well as the fine arts field.