• Title/Summary/Keyword: Power Flow problem

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A study on role of ROK Escort Task Gruop according to recently Pirate Conducting Trend and Anti-Piracy Operation in Indian Ocean (최근 인도양 해적활동과 대해적작전 변화에 따른 한국 청해부대 역할 연구)

  • Choi, Hyoung-Min
    • Strategy21
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    • s.32
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    • pp.192-221
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    • 2013
  • In order to deal with the current economic crisis, the U.S. government, as a part of its austerity fiscal policy, implemented a budget sequester. The sequester will hit the U.S. defense budget the hardest, and as a result will most likely put the security of the international community in jeopardy. The U.S. will have to cut 46 billion dollars from its original 525 billon defense spending in 2013. And by the year 2022, will have to cut 486.9 billion dollars. Such an astronomical decrease in the U.S. defense spending will inevitably burden the friendly nations. According to recent studies, pirate related incidents in Somalia, where piracy is most active, has declined from its 226 incidents to 76 incidents per year in 2012, a 66% drop from previous years'. However, piracy threats as well as those related to firearms still remain and thus participants of anti-piracy operations, namely the U.S., U.K., France, Canada, NCC, EUNAVFOR, and NATO, are facing a problem of declining forces. Considering the current situation as well as rising expectations from the international community, Republic of Korea, a supporter of NCC's maritime security operation, not to mention its foremost duty of securing its sea, is at a stage to re-examine its operational picture. Such action will be a good opportunity for Republic of Korea to build the trust and live up to the international community's expectation. To quote from the network theory, although in relation to other friendly nations participating in the anti-piracy operation, Republic of Korea currently remains at a single cell level, this opportunity will certainly develop Korea to a 'node' nation in which power and information would flow into. Through this expansion of operational capability, Republic of Korea will be able to exert more influence as a more developed nation. Currently however, not only is the single 4,500 ton class destroyer deployed in Somalia a limited unit to further expand the scale and amount of force projection in the area, but also the total of six 4,500 ton class destroyers ROK feet possess is at a high fatigue degree due to standard patrolling operations, midshipman cruise and the RIMPAC exercise. ROK fleet therefore must consider expanding the number of ships deployed along with either deploying combat support ships or constructing logistics support site in the African region. Thus, by expanding its operational capabilities and furthermore by abiding to the rightful responsibilities of a middle power nation, Republic of Korea will surely earn its respect among the members of the international community.

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A Dynamic Management Method for FOAF Using RSS and OLAP cube (RSS와 OLAP 큐브를 이용한 FOAF의 동적 관리 기법)

  • Sohn, Jong-Soo;Chung, In-Jeong
    • Journal of Intelligence and Information Systems
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    • v.17 no.2
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    • pp.39-60
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    • 2011
  • Since the introduction of web 2.0 technology, social network service has been recognized as the foundation of an important future information technology. The advent of web 2.0 has led to the change of content creators. In the existing web, content creators are service providers, whereas they have changed into service users in the recent web. Users share experiences with other users improving contents quality, thereby it has increased the importance of social network. As a result, diverse forms of social network service have been emerged from relations and experiences of users. Social network is a network to construct and express social relations among people who share interests and activities. Today's social network service has not merely confined itself to showing user interactions, but it has also developed into a level in which content generation and evaluation are interacting with each other. As the volume of contents generated from social network service and the number of connections between users have drastically increased, the social network extraction method becomes more complicated. Consequently the following problems for the social network extraction arise. First problem lies in insufficiency of representational power of object in the social network. Second problem is incapability of expressional power in the diverse connections among users. Third problem is the difficulty of creating dynamic change in the social network due to change in user interests. And lastly, lack of method capable of integrating and processing data efficiently in the heterogeneous distributed computing environment. The first and last problems can be solved by using FOAF, a tool for describing ontology-based user profiles for construction of social network. However, solving second and third problems require a novel technology to reflect dynamic change of user interests and relations. In this paper, we propose a novel method to overcome the above problems of existing social network extraction method by applying FOAF (a tool for describing user profiles) and RSS (a literary web work publishing mechanism) to OLAP system in order to dynamically innovate and manage FOAF. We employed data interoperability which is an important characteristic of FOAF in this paper. Next we used RSS to reflect such changes as time flow and user interests. RSS, a tool for literary web work, provides standard vocabulary for distribution at web sites and contents in the form of RDF/XML. In this paper, we collect personal information and relations of users by utilizing FOAF. We also collect user contents by utilizing RSS. Finally, collected data is inserted into the database by star schema. The system we proposed in this paper generates OLAP cube using data in the database. 'Dynamic FOAF Management Algorithm' processes generated OLAP cube. Dynamic FOAF Management Algorithm consists of two functions: one is find_id_interest() and the other is find_relation (). Find_id_interest() is used to extract user interests during the input period, and find-relation() extracts users matching user interests. Finally, the proposed system reconstructs FOAF by reflecting extracted relationships and interests of users. For the justification of the suggested idea, we showed the implemented result together with its analysis. We used C# language and MS-SQL database, and input FOAF and RSS as data collected from livejournal.com. The implemented result shows that foaf : interest of users has reached an average of 19 percent increase for four weeks. In proportion to the increased foaf : interest change, the number of foaf : knows of users has grown an average of 9 percent for four weeks. As we use FOAF and RSS as basic data which have a wide support in web 2.0 and social network service, we have a definite advantage in utilizing user data distributed in the diverse web sites and services regardless of language and types of computer. By using suggested method in this paper, we can provide better services coping with the rapid change of user interests with the automatic application of FOAF.

Bottom electrode optimization for the applications of ferroelectric memory device (강유전체 기억소자 응용을 위한 하부전극 최적화 연구)

  • Jung, S.M.;Choi, Y.S.;Lim, D.G.;Park, Y.;Song, J.T.;Yi, J.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.8 no.4
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    • pp.599-604
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    • 1998
  • We have investigated Pt and $RuO_2$ as a bottom electrode for ferroelectric capacitor applications. The bottom electrodes were prepared by using an RF magnetron sputtering method. Some of the investigated parameters were a substrate temperature, gas flow rate, RF power for the film growth, and post annealing effect. The substrate temperature strongly influenced the surface morphology and resistivity of the bottom electrodes as well as the film crystallographic structure. XRD results on Pt films showed a mixed phase of (111) and (200) peak for the substrate temperature ranged from RT to $200^{\circ}C$, and a preferred (111) orientation for $300^{\circ}C$. From the XRD and AFM results, we recommend the substrate temperature of $300^{\circ}C$ and RF power 80W for the Pt bottom electrode growth. With the variation of an oxygen partial pressure from 0 to 50%, we learned that only Ru metal was grown with 0~5% of $O_2$ gas, mixed phase of Ru and $RuO_2$ for $O_ 2$ partial pressure between 10~40%, and a pure $RuO_2$ phase with $O_2$ partial pressure of 50%. This result indicates that a double layer of $RuO_2/Ru$ can be grown in a process with the modulation of gas flow rate. Double layer structure is expected to reduce the fatigue problem while keeping a low electrical resistivity. As post anneal temperature was increased from RT to $700^{\circ}C$, the resistivity of Pt and $RuO_2$ was decreased linearly. This paper presents the optimized process conditions of the bottom electrodes for memory device applications.

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Impacts of Immigrant Workers on Regional Economy in S. Korea (이주노동자의 유입이 지역경제에 미치는 영향)

  • Choi, Byung-Doo
    • Journal of the Korean association of regional geographers
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    • v.15 no.3
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    • pp.369-392
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    • 2009
  • Recently international movements of labour as well as those of goods and other production elements such as capitals and technology have been increased rapidly under the process of glocalization. The huge amount of immigrant workers' in-flows makes increasing influences on regional economy in South Korea. This paper examines such impacts of immigrant workers on local labor markets, productivity. and industrial composition and innovation on the basis of analysis of empirical data and review of existing literature on the subject. Despite a problem of simplification, some reasoning can be listed as follows: First of all, the inflow of immigrant workers has an effect of job displacement among domestic simple workers, with duel effects on the status of native workers; secondly, Immigrant workers give a positive effect on local productivity, but only with low level of wage and of purchasing power; thirdly, the in-flow of immigrant workers seems to prevent existing industries from transformation towards new ones and/or from automation and innovation of production facilities, while there seems no clear relationship with foreign direct investments of local firms.

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High Performance Flexible Inorganic Electronic Systems

  • Park, Gwi-Il;Lee, Geon-Jae
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.115-116
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    • 2012
  • The demand for flexible electronic systems such as wearable computers, E-paper, and flexible displays has increased due to their advantages of excellent portability, conformal contact with curved surfaces, light weight, and human friendly interfaces over present rigid electronic systems. This seminar introduces three recent progresses that can extend the application of high performance flexible inorganic electronics. The first part of this seminar will introduce a RRAM with a one transistor-one memristor (1T-1M) arrays on flexible substrates. Flexible memory is an essential part of electronics for data processing, storage, and radio frequency (RF) communication and thus a key element to realize such flexible electronic systems. Although several emerging memory technologies, including resistive switching memory, have been proposed, the cell-to-cell interference issue has to be overcome for flexible and high performance nonvolatile memory applications. The cell-to-cell interference between neighbouring memory cells occurs due to leakage current paths through adjacent low resistance state cells and induces not only unnecessary power consumption but also a misreading problem, a fatal obstacle in memory operation. To fabricate a fully functional flexible memory and prevent these unwanted effects, we integrated high performance flexible single crystal silicon transistors with an amorphous titanium oxide (a-TiO2) based memristor to control the logic state of memory. The $8{\times}8$ NOR type 1T-1M RRAM demonstrated the first random access memory operation on flexible substrates by controlling each memory unit cell independently. The second part of the seminar will discuss the flexible GaN LED on LCP substrates for implantable biosensor. Inorganic III-V light emitting diodes (LEDs) have superior characteristics, such as long-term stability, high efficiency, and strong brightness compared to conventional incandescent lamps and OLED. However, due to the brittle property of bulk inorganic semiconductor materials, III-V LED limits its applications in the field of high performance flexible electronics. This seminar introduces the first flexible and implantable GaN LED on plastic substrates that is transferred from bulk GaN on Si substrates. The superb properties of the flexible GaN thin film in terms of its wide band gap and high efficiency enable the dramatic extension of not only consumer electronic applications but also the biosensing scale. The flexible white LEDs are demonstrated for the feasibility of using a white light source for future flexible BLU devices. Finally a water-resist and a biocompatible PTFE-coated flexible LED biosensor can detect PSA at a detection limit of 1 ng/mL. These results show that the nitride-based flexible LED can be used as the future flexible display technology and a type of implantable LED biosensor for a therapy tool. The final part of this seminar will introduce a highly efficient and printable BaTiO3 thin film nanogenerator on plastic substrates. Energy harvesting technologies converting external biomechanical energy sources (such as heart beat, blood flow, muscle stretching and animal movements) into electrical energy is recently a highly demanding issue in the materials science community. Herein, we describe procedure suitable for generating and printing a lead-free microstructured BaTiO3 thin film nanogenerator on plastic substrates to overcome limitations appeared in conventional flexible ferroelectric devices. Flexible BaTiO3 thin film nanogenerator was fabricated and the piezoelectric properties and mechanically stability of ferroelectric devices were characterized. From the results, we demonstrate the highly efficient and stable performance of BaTiO3 thin film nanogenerator.

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Photocatalyst characteristic of WO3 thin film with sputtering process (스퍼터링법에 의해 제작된 WO3 박막의 광분해 특성)

  • Lee, Boong-Joo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.7
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    • pp.420-424
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    • 2016
  • In this study, we developed photocatalytic technology to address the emerging serious problem of air pollution through indoor air cleaning. A single layer of $WO_3$ was prepared by using the dry process of general RF magnetron sputtering. At a base vacuum of $1.8{\times}10^{-6}$[Torr], the optical and electrical properties of the resulting thin films were examined for use as a transparent electrode as well as a photocatalyst. The single layer of $WO_3$ prepared at an RF power of 100 [W], a pressure of 7 [mTorr] and Ar and $O_2$ gas flow rates of 70 and 2 sccm, respectively, showed uniform and good optical transmittance of over 80% in the visible wavelength range from 380 [nm] to 780 [nm]. The optical catalyst characteristics of the $WO_3$ thin film were examined by investigating the optical absorbance and concentration variance in methylene blue, where the $WO_3$ thin film was immersed in the methylene blue. The catalytic characteristics improved with time. The concentration of methylene blue decreased to 80% after 5 hours, which confirms that the $WO_3$ thin film shows the characteristics of an optical catalyst. Using the reflector of a CCFL (cold cathode fluorescent lamp) and the lens of an LED (lighting emitting diode), it is possible to enhance the air cleaning effect of next-generation light sources.

Numerical Analysis of Resin Filling Process for a Molded Dry-type Potential Transformer (몰드형 건식 계기용 변압기 제작을 위한 수지 충진 해석 연구)

  • Kim, Moosun;Jang, Dong Uk;Kim, Seung Mo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.12
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    • pp.511-517
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    • 2016
  • Current oil-type potential transformers for trains are filled with insulating oil, which could have problems like explosions due to rising inner pressure during train operation. Therefore, mold and dry-type potential transformers are being developed to prevent explosions. One problem in manufacturing mold-type transformers is preventing void formation around the coiled core inside the mold during epoxy filling, which could cause an electrical spark. Micro voids can remain in the resin after filling, and macro voids can occur due to the structure shape. A transformer that is being developed has a cavity at the junction of the core and the coil for better performance, and when highly viscous epoxy flows inside the cavity channel, macro voids can form inside it. Therefore, in this study, the free-surface flow of the mold filling procedure was analyzed numerically by applying the VOF method. The results were used to understand the phenomena of void formation inside the cavity and to modify the process conditions to reduce voids.

A Study on the Taboo of Marriage Luxury of Chosun Period (조선시대 혼인사치의 금제에 관한 고찰)

  • 김경희
    • The Research Journal of the Costume Culture
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    • v.6 no.1
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    • pp.1-13
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    • 1998
  • As for the taboo of dress and its ornaments which was applied to only populace one-sidedly mainly under the power structure of feudalistic centralization of government like Chosun dynasty, the aspect of taboo was diversified all the more by having relation with various phenomenon of social structure characteristics, and the taboo items to be given in accordance with the flow of time shows the diversity. Especially, the structure of dress and its ornaments in Chosun period showed the side of social position relation and luxury control, and the taboo of dress and its ornaments which was derived from the current thought about China was given frequently. To respect the frugal virtue and moderate the life has relation with the stream of the times in individuals or nations. And, that it is externalized is dress and its ornaments. As the luxury about dress and its ornaments was serious in accordance with times, it appeared by having relation with whole economic question of nations. Then, this researcher thought this by relating this to the culture of customs. This researcher thought that the luxury about clothing gets to go to extremes and the law and order collapses, according as public morals get to be very lax. And, it can be said that the way to be able to control this is that the customs should be thoroughly obeyed and that the system to be able to play the role of braking is taboo. So, this researcher thinks that it is significant to examine the achievement which has contributed toward the life of dress and its ornaments by successive kinds on the basis of a true record of the Vidynasty and other all sorts of literatures about the real situation of prohibition order which has been from the first king to Kojong at the last period of nation. The criticism and taboo about luxury which have been discussed at Chosun period may be subdivided into some kinds in accordance with the subjects. But, in this tests, as it sis the real situation that the case to be due to the lavish necessary articles for marriage which is coming to fore as our social problem nowadays is increasing remarkably, this researcher tries to examine the taboo about the marriage luxury at Chosun period in the order of successive generations. Thus, before examining the taboo of marriage luxury, this researcher tries to examine about the taboo of textile luxury and study the taboo of marriage luxury, as the marriage luxury governs almost everything of textile luxury and it is regarded as the origin of marriage luxury, especially. And, this researcher tries to study as to how was the penal regulations based on it at the same time.

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Implementation of a TCP/IP Offload Engine Using High Performance Lightweight TCP/IP (고성능 경량 TCP/IP를 이용한 소프트웨어 기반 TCP/IP 오프로드 엔진 구현)

  • Jun, Yong-Tae;Chung, Sang-Hwa;Yoon, In-Su
    • Journal of KIISE:Computing Practices and Letters
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    • v.14 no.4
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    • pp.369-377
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    • 2008
  • Today, Ethernet technology is rapidly developing to have a bandwidth of 10Gbps beyond 1Gbps. In such high-speed networks, the existing method that host CPU processes TCP/IP in the operating system causes numerous overheads. As a result of the overheads, user applications cannot get the enough computing power from the host CPU. To solve this problem, the TCP/IP Offload Engine(TOE) technology was emerged. TOE is a specialized NIC which processes the TCP/IP instead of the host CPU. In this paper, we implemented a high-performance, lightweight TCP/IP(HL-TCP) for the TOE and applied it to an embedded system. The HL-TCP supports existing fundamental TCP/IP functions; flow control, congestion control, retransmission, delayed ACK, processing out-of-order packets. And it was implemented to utilize Ethernet MAC's hardware features such as TCP segmentation offload(TSO), checksum offload(CSO) and interrupt coalescing. Also we eliminated the copy overhead from the host memory to the NIC memory when sending data and we implemented an efficient DMA mechanism for the TCP retransmission. The TOE using the HL-TCP has the CPU utilization of less than 6% and the bandwidth of 453Mbps.

Formation and Characteristics of the Fluorocarbonated SiOF Film by $O_2$/FTES-Helicon Plasma CVD Method

  • Kyoung-Suk Oh;Min-Sung Kang;Chi-Kyu Choi;Seok-Min Yun
    • Proceedings of the Korean Vacuum Society Conference
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    • 1998.02a
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    • pp.77-77
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    • 1998
  • Present silicon dioxide (SiOz) 떠m as intennetal dielectridIMD) layers will result in high parasitic c capacitance and crosstalk interference in 비gh density devices. Low dielectric materials such as f f1uorina뼈 silicon oxide(SiOF) and f1uoropolymer IMD layers have been tried to s이ve this problem. I In the SiOF ftlm, as fluorine concentration increases the dielectric constant of t뼈 film decreases but i it becomes unstable and wa않r absorptivity increases. The dielectric constant above 3.0 is obtain어 i in these ftlms. Fluoropolymers such as polyte$\sigma$따luoroethylene(PTFE) are known as low dielectric c constant (>2.0) materials. However, their $\alpha$)Or thermal stability and low adhesive fa$\pi$e have h hindered 야1리ru뚱 as IMD ma따"ials. 1 The concept of a plasma processing a찌Jaratus with 비gh density plasma at low pressure has r received much attention for deposition because films made in these plasma reactors have many a advantages such as go여 film quality and gap filling profile. High ion flux with low ion energy in m the high density plasma make the low contamination and go어 $\sigma$'Oss피lked ftlm. Especially the h helicon plasma reactor have attractive features for ftlm deposition 야~au똥 of i앙 high density plasma p production compared with other conventional type plasma soun:es. I In this pa야Jr, we present the results on the low dielectric constant fluorocarbonated-SiOF film d밑JOsited on p-Si(loo) 5 inch silicon substrates with 00% of 0dFTES gas mixture and 20% of Ar g gas in a helicon plasma reactor. High density 띠asma is generated in the conventional helicon p plasma soun:e with Nagoya type ill antenna, 5-15 MHz and 1 kW RF power, 700 Gauss of m magnetic field, and 1.5 mTorr of pressure. The electron density and temperature of the 0dFTES d discharge are measUI벼 by Langmuir probe. The relative density of radicals are measured by optic허 e emission spe따'Oscopy(OES). Chemical bonding structure 3I피 atomic concentration 따'C characterized u using fourier transform infrared(FTIR) s야3띠"Oscopy and X -ray photonelectron spl:’따'Oscopy (XPS). D Dielectric constant is measured using a metal insulator semiconductor (MIS;AVO.4 $\mu$ m thick f fIlmlp-SD s$\sigma$ucture. A chemical stoichiome$\sigma$y of 야Ie fluorocarbina$textsc{k}$영-SiOF film 따~si야영 at room temperature, which t the flow rate of Oz and FTES gas is Isccm and 6sccm, res야~tvely, is form려 야Ie SiouFo.36Co.14. A d dielec$\sigma$ic constant of this fIlm is 2.8, but the s$\alpha$'!Cimen at annealed 5OOt: is obtain려 3.24, and the s stepcoverage in the 0.4 $\mu$ m and 0.5 $\mu$ m pattern 킹'C above 92% and 91% without void, res야~tively. res야~tively.

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