• Applied Chemistry for Engineering
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• v.17 no.4
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• pp.420-425
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• 2006

Nano sized mixed metal hexagonal ferrite powders with improved magnetic properties have been prepared by sol-gel method using propylene oxide as a gelation agent. To obtain the desired ferrite, two different metal ions were used. One of the ions has only +2 formal charge. The key step in the processes is that hydrated $Ba^{2+}$ or $Sr^{2+}$ ions are hydrolyzed and condensed at the surface of the previously formed $Fe_{2}O_{3}$ gel. In this processes, all the reaction can be finished within a few minutes. The magnetic properties of the produced powder were improved by heat treatment. The highest values of the magnetic properties were achieved at temperature $150^{\circ}C$ lower than those of the previously published values. The highest observed values of coercivity and the saturation magnetization of Sr-ferrite and Ba-ferrite powder were 6198 Oe, 5155 Oe and 74.4 emu/g, 68.1 emu/g, respectively. The ferrite powder annealed at $700^{\circ}C$ showed spherical particle shapes. The resulting spheres which were formed by the aggregation of nanoparticles with size 3~5 nm have diameter around 50 nm. The powder treated at $800^{\circ}C$ showed hexagonal-shaped grains with crystallite size above 500 nm.

• Journal of Internet Computing and Services
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• v.12 no.4
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• pp.35-43
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• 2011

Cognitive Radio (CR) ad hoc network is highly considered as one of promising future ad hoc networks, which enables opportunistic access to under-utilized licensed spectrum. Similarly to other CR networks, the spectrum sensing is a prerequisite in CR ad hoc network. Collaborative spectrum sensing can help increasing sensing performance. For such an infrastructureless network, however the coordination for the sensing collaboration is really complicated due to the lack of a central controller. In this paper, we propose a novel collaborative spectrum sensing scheme in which the final decision is made by the node with the highest data reliability based on a sequential Dempster Shafer theory. The collaboration of sensing data is also executed by the proposed contention-aware reporting mechanism which utilizes the sensing data reliability order for broadcasting spectrum sensing result. The proposed method reduces the collecting time and the overhead of the control channel due to the efficiency of the ordered sequential combination while keeping the same sensing performance in comparison with the conventional cooperative centralized spectrum sensing scheme.

• Korean Journal of Food Science and Technology
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• v.26 no.1
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• pp.26-30
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• 1994

The purpose of this study was to investigate the effects of heating times of soy protein isolate(SPI) and mixing ratio of coagulants mixture on water holding capacity(WHC) and oil absorption capacity (OAC) of SPI, texture properties and yield of tofu. The effect of heating at $100^{\circ}C$ on the amounts of coagulants required for coagulation showed that the amounts of $CaCl_{2},\;MgCl_{2}$ and GDL decreased as the heating time extended to $6{\sim}9$ minutes while $CaSO_{2}$ was changed little. The tofu yield showed maximum for the tofu prepared by 6 minutes boiling and coagulation with $CaSO_{4}$. The WHC of SPI was significantly reduced by heating at $100^{\circ}C$ while OAC was rather increased until 9 minutes of heating. The textural properties of SPI tofu coagulated with mixed coagulants$(CaSO_{4}-GDL,\;CaSO_{4}-CaCl_{2},\;CaCl_2-GDL)$ showed that softer tofu was obtained as the ratio of $CaSO_{2}$ increased and harder tofu as the ratio of $CaCl_{2}$ and GDL increased. The maximum and minimum tofu yields were prepared from 100% of $CaSO_{2}$ and 100% of GDL, respectively. Organoleptic properties showed that more uniform and tender tofu were obtained with higher portion of $CaSO_{2}$ in the mixed coagulants and higher intensity of sourness and bitterness were scored as the GDL and $CaCl_{2}$ added more.

• Journal of radiological science and technology
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• v.40 no.2
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• pp.205-211
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• 2017

There is a need for aggressive diagnosis and treatment in middle-aged and high-risk individuals who are more likely to progress from nonalcoholic fatty liver to hepatitis. In this study, nonalcoholic fatty liver was divided into severe, moderate, and severe, and classified by quantitative method using computer analysis of GLCM algorithm. The purpose of this study was to evaluate the characteristics of ultrasound images in the local fat avoidance region. Normal, mild, moderate, severe fatty liver, and focal fat sparing area, 80 cases, respectively. Among the parameters of the GLCM algorithm, the values of the Autocorrelation, Square of the deviation, Sum of averages and Sum of variances with high recognition rate of the liver ultrasound image were calculated. The average recognition rate of the GLCM algorithm was 97.5%. The result of local fat avoidance image analysis showed the most similar value to the normal parenchyma. Ultrasonography can be easily accessed by primary screening, but there may be differences in the accuracy of the test method or the correspondence of results depending on proficiency. GLCM algorithm was applied to quantitatively classify the degree of fatty liver. Local fat avoidance region was similar to normal parenchyma, so it could be predicted to be homogeneous liver parenchyma without fat deposition. We believe that GLCM computer image analysis will provide important information for differentiating not only fatty liver but also other lesions.

• Journal of Korean Society of Steel Construction
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• v.14 no.6
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• pp.773-782
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• 2002

In this study, a series of fatigue tests are performed in order to estimate quantitatively the characteristics of fatigue crack growth rate according to the base metal, heat affected zone(HAZ) and weld metal, and the welding method and grade of strength of object steels, and the influence on fatigue crack growth rate according to the direction of welded line for high strength steels of SM570, POSTEN60, and POSTEN80 steels. From the fatigue test results, the retardations of fatigue crack growth rate are remarkable in case that the direction of notch is parallel to welded line than in case that the direction of notch is perpendicular to welded line because of compresive residual stress in weld metal & HAZ. And the characteristics of fatigue crack growth rate according to welding method are that the dispersion of fatigue crack growth rate in case of FCAW method is smaller than that of SAW method. Also, it knows that the fatigue crack growth rate converges in high stress intensity factor range. Meanwhile, fatigue safety is guaranteed sufficiently in the object steels because the fatigue crack growth rate in the range of fatigue crack propagation has a similar tendency to the test results & existing results.

• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.4
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• pp.74-82
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• 2008

The purpose of this study is to reflect on the results of the assessment and analysis of landscape planning projects according to planning phases in a landscape planning system based on landscape law. An assessment of the importance and performance of landscape planning elements by planning phases was studied by statistically descriptive analysis, variation analysis, statistical t-test and importance-performance analysis. As a result of the evaluation, the performance of existing landscape planning projects is 3.813 and the importance of planning elements is 5.648. This means that in spite of the importance of landscape planning elements, the performance of existing landscape planning projects is not sufficient to cover the importance of landscape planning elements. In addition, 'site landscape survey' and 'landscape design guideline' sections are not sufficient when they are compared to 'landscape concept plan' and 'landscape basic plan' to complete the landscape planning projects required by landscape law. It means also that the landscape survey and landscape design guidelines should be complementarily practiced in order to increase the effectiveness of landscape planning projects. As the research is practiced by survey methods on landscape planning projects which are only new development sites, the results cannot represent all types of landscape planning projects. Nevertheless, the results can be applied to new landscape planning at new development sites or old cities to increase effectiveness.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10c
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• pp.246-251
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• 2006

마이크로어레이 실험은 수 천에서 수 만개의 유전자 발현 결과를 동시에 측정할 수 있어 질병의 발현 형질 분류 등에 유용하게 이용되고 있다. 그러나 마이크로어레이 실험은 동일한 플랫폼의 실험이라 할지라도 환경 등에 따라 그 실험 결과에 차이가 나는 등 오차를 항상 포함하고 있다. 또한 마이크로어레이 실험은 아직 고가의 실험으로 분류되어 다수의 샘플에 대한 반복 실험 결과를 얻기 어려운 상황이다. 따라서 이종의 플랫폼, 데이터 포맷, 정규화 기법 등이 서로 다른 데이터를 효율적으로 통합하여 유용한 정보를 추출하는 새로운 방식의 개발이 필요하다. 본 논문은 이와 같은 문제를 해결하기 위한 기초 단계 연구 결과이다. 마이크로어레이 실험 데이터로부터 통계적 방법을 이용하여 유의(informative) 유전자를 추출하고 유전자 온톨로지(Gene Ontology : GO)와의 연계를 통하여 유전자 정보의 기능적 분류 결과를 사용자에게 제공하는 유전자 기능 분석 시스템의 설계 및 구현 방안을 보인다. 본 시스템의 실험방법에서는 3-Fold Filtering 기법을 통하여 발현 차가 큰 유전자를 추출하고, t-검정 기법에 의하여 이들 유전자를 순위화 하였으며, 이 중 상위 100개의 유전자를 유의 유전자로 추출하였다. 다음, 이 들 유의 유전자의 t-검정 값을 GO의 유전자 기능을 나타내는 해당 텀 (term)에 가중치로 부과하여 각 유전자들과 기능적으로 연관성이 높은 텀들을 추출한다. 또한 본 연구의 유효성을 검증하기 위하여 본 시스템에 의한 마이크로어레이 데이터 분석 결과를 전문가에 의한 유전자 기능 분석 결과와 비교한다.투명성 있는 서비스를 제공하고 높은 신뢰성과 안정성이 확보될 수 있도록 구성하고자 한다. Query 수행을 여러 서버로 분산처리하게 함으로써 성능에 대한 신뢰성을 향상 시킬 수 있는 Load Balancing System을 제안한다.할 때 가장 효과적인 라우팅 프로토콜이라고 할 수 있다.iRNA 상의 의존관계를 분석할 수 있었다.수안보 등 지역에서 나타난다 이러한 이상대 주변에는 대개 온천이 발달되어 있었거나 새로 개발되어 있는 곳이다. 온천에 이용하고 있는 시추공의 자료는 배제하였으나 온천이응으로 직접적으로 영향을 받지 않은 시추공의 자료는 사용하였다 이러한 온천 주변 지역이라 하더라도 실제는 온천의 pumping 으로 인한 대류현상으로 주변 일대의 온도를 올려놓았기 때문에 비교적 높은 지열류량 값을 보인다. 한편 한반도 남동부 일대는 이번 추가된 자료에 의해 새로운 지열류량 분포 변화가 나타났다 강원 북부 오색온천지역 부근에서 높은 지열류량 분포를 보이며 또한 우리나라 대단층 중의 하나인 양산단층과 같은 방향으로 발달한 밀양단층, 모량단층, 동래단층 등 주변부로 NNE-SSW 방향의 지열류량 이상대가 발달한다. 이것으로 볼 때 지열류량은 지질구조와 무관하지 않음을 파악할 수 있다. 특히 이러한 단층대 주변은 지열수의 순환이 깊은 심도까지 가능하므로 이러한 대류현상으로 지표부근까지 높은 지온 전달이 되어 나타나는 것으로 판단된다.의 안정된 방사성표지효율을 보였다. $^{99m}Tc$-transferrin을 이용한 감염영상을 성공적으로 얻을 수 있었으며, $^{67}Ga$-citrate

• The KIPS Transactions:PartD
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• v.11D no.1
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• pp.105-114
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• 2004

In this paper, we propose a collaboration method of diverse agents each others in multi-agent model and describe a node migration algorithm of Mobile-Agent (MA) using by the metadata of Naming-Agent (NA). Collaboration work of multi-agent assures stability of agent system and provides reliability of information retrieval on the distributed environment. NA, an important part of multi-agent, identifies each agents and series the unique name of each agents, and each agent references the specified object using by its name. Also, NA integrates and manages naming service by agents classification such as Client-Push-Agent (CPA), Server-Push-Agent (SPA), and System-Monitoring-Agent (SMA) based on its characteristic. And, NA provides the location list of mobile nodes to specified MA. Therefore, when MA does move through the nodes, it is needed to improve the efficiency of node migration by specified priority according to hit_count, hit_ratio, node processing and network traffic time. Therefore, in this paper, for the integrated naming service, we design Naming Agent and show the structure of metadata which constructed with fields such as hit_count, hit_ratio, total_count of documents, and so on. And, this paper presents the flow of creation and updating of metadata and the method of node migration with hit_count through the collaboration of multi-agent.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.1
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• pp.1-17
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• 2008

Recently, the object based storage devices systems(OSDs) have been actively researched. They are different from existing block based storage systems(BSDs) in terms of the storage unit. The storage unit of the OSDs is an object that includes the access methods, the attributes of data, the security information, and so on. The object has no size limit and no influence on the internal storage structures. Therefore, the OSDs improve the I/O throughput and the scalability. But the backup systems for the OSDs still use the existing backup techniques for the BSDs. As a result, they need much backup time and do not utilize the characteristics of the OSDs. In this paper, we design and implement a new object based backup system that utilizes the features of the OSDs. Our backup system significantly improves the backup time over existing backup systems because the raw objects are directly transferred to the backup devices in our system. It also restores the backup data much faster than the existing systems when system failures occur. In addition, it supports various types of backup and restore requests.

• Progress in Medical Physics
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• v.9 no.3
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• pp.185-192
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• 1998

It is necessarily to evaluate the energy of X-ray emitted from linear accelerator in order to determine the accurate absorbed dose. The method of direct measurement for x-ray energy is very difficult and impractical. Therefore the method of using beam quality index is generally used. Several dosimetry protocols recommend the use of quality indices such as depth of dose maximum at radiation central axis, dose gradient, and dose level. The linear accelerator manufactures follow the recommendation as dosimetry protocols. The study was performed for us to select the most suitable parameter among the Quality indices as described above. For photon beams of 4, 6, 10, 15, and 21 MV nominal energies produced by four kinds of accelerators(Mitsubishi, Scanditronix, Siemens, Varian) in eleven institutions, We evaluated the x-ray energies obtained by the Quality indices as recommended by several dosimetry protocols and manufactures. Results showed that there were energy spreads according to the same accelerators and Quality indices even though nominal energies were same. It appeared that the percent depth dose at 10 cm (D$_{10}$(%)) gave the smallest deviation and spread of energies. As energies increased, the energy deviation increased for all the quality indices. It is desirable for the use of unified quality index to compare the evaluation of beam quality at different institutions.