• Journal of the Mineralogical Society of Korea
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• v.14 no.1
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• pp.73-84
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• 2001

티타늄과 산소의 함량이 서로 다른 4가지의 합성 페롭스카이트형(perovskite-type) 광물(($K_2$$La_2$$Ti_{n}$/$O_{2n+4}$, n=3, 4, 5, 6; 14/mcm, 14/mmm, I42 m)을 대상으로 리트벨트(Rietveld)구조분석법을 실시하여 결정구조를 밝히고 티타늄함량에 따른 층상형 구조를 연구하였다. 4가지 합성시료에 대하여 구조분석을 실시한결과 대표적인 페롭스카이트형 광물인 토소나이트(taustonite, $La_{1-x}$ //$K_{x}$ /$TiO_3$, x<0.4)가 주성분으로 나타났으며 토스나이트내에 12개의 산소를 배위하는 A자리 양이온은 자리점유율에 의해 $La^{3+}$ 와 $K^{+}$ /의 치환관계를 보여준다 공간군은 14/mcm, 단위포는 a=5.505(1)~5.510(1)$\AA$, c=7.793(1)~7.796(1)$\AA$ V=236.25~236.66 $\AA^3$ 범위의 값을 갖는다. 구조의 정밀도를 나타내는 R지수를 살펴보면 $R_{B}$ 값은 5.31~9.10 S(GofF)값은 0.86~1.24로 각각 계산되었다. 12배위를 하는 A자리 양이온인 란탄과 산소의 평균거리는 2.755$\AA$이고 6배위를 하는 B자리 양이온인 티타늄과 산소의 평균거리는 1.948 $\AA$의 결과를 얻었다. 합성된페롭스카이트형 광물의 층상구조가 알려져 있지 않아 시뮬레이션을 통해 구조모델을 결정하였으며 그결과 n=3인 R-38시료에서만 두 종류의 층상 페롭스카이트($La_2$$K_2$$Ti_3$$O_{10}$ ) 구조 (A-type: 14/mmm, a=3.8178 $\AA$, c=29.9189 $\AA$, V=436.04 $\AA^3$, B-type: 142 m, a =3.8376 $\AA$, c=28.023 $\AA$, V=412.6 $\AA^3$)가 존재함을 확인하였으나 다른 시료에서는 토소나이트, 금홍석 외에 새로운 합성광물로 제파이트의 존재를 확인하였다.

• Journal of Korean Association for Spatial Structures
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• v.10 no.4
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• pp.93-102
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• 2010

In this study, a smart sky-bridge composed of MR damper and FPS has been proposed and vibration control performance of a smart sky-bridge for the connected buildings was investigated. To this end, 10-story and 20-story building structures connected by a smart sky-bridge were selected as example structures and El Centro and Kobe earthquakes, which have near and far fault ground motion characteristics respectively, were used for time history analyses. In order to effectively control the smart sky-bridge, fuzzy logic controller was developed and multi-objective genetic algorithm was used to optimize fuzzy logic controllers. Based on optimization results, it has been seen that there is a trade-off between seismic responses of 10-story and 20-story buildings and a suite of Pareto optimal solutions of fuzzy logic controllers for seismic response control can be obtained by multi-objective genetic algorithm. It is shown from numerical study that seismic responses of adjacent buildings can be efficiently controlled by using a smart sky-bridge.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.4
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• pp.289-293
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• 2009

In sensor networks, many methods have been proposed to process in-network aggregation effectively. Contrary to normal aggregation queries, skyline query processing that compare multi-dimension data for producing result is very hard. It is important to filter unnecessary data for energy-efficient skyline query processing. Existing approach like MFTAC restricts unnecessary data transitions by deploying filters to whole sensors. However, network lifetime is reduced by energy consumption for filters transmission. In this paper, we propose a lazy filtering-based skyline query processing algorithm of in-network for reducing energy consumption by filters transmission. The proposed algorithm creates the skyline filter table (SFT) in the data gathering process which sends from sensor nodes to the base station and filters out unnecessary transmissions using it. The experimental results show that the proposed algorithm reduces false positive by 53% and improves network lifetime by 44% on average over MFTAC.

• KIPS Transactions on Software and Data Engineering
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• v.1 no.1
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• pp.7-18
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• 2012

It has been studied to support data having multiple properties, called Skyline Query. The skyline query is not exploring data having all properties but only meaningful data, when we retrieve informations in large data base. The skyline query can be used to provide some information about various environments and situations in sensor network. However, the legacy skyline query has a problem that increases the number of comparisons as the number of sensors are increasing in multi-dimensional data. Also important values are often omitted. Therefore, we propose a new method to reduce the complexity of comparison where the large number of sensors are placed. To reduce the complexity, we transfer a CMF(Category Based Member Function) which can identify preference of specific data when interest query from sync-node is transferred to sub-node. To show the validity of our method, we analyzed the performance by simulations. As a result, it showed that the time complexity was reduced when we retrieved information in multiple sensing data and omitted values are detected by great dominance Skyline.

• Journal of KIISE:Databases
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• v.33 no.6
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• pp.631-643
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• 2006

Moving objects in a mobile environment to change their position based on the change of time require a query with their position as a basis. Efficient Regional Decision for Continuous Skyline Queries requires objectively pre-calculating the OSR(Optimal Skyline Region) regardless of the speed and direction of the moving objects. It proposes techniques to reduce the frequency of continuous queries by choosing a VCircle(Validity Circle) as safe location which has radius of the distance to the closest region with position on the moving object at center. But, a VCircle's area varies based on the Moving object's position from first marked time of continuous query. Therefore, the frequency of its continuous query is variable and also when the object moves inside of OSR, query can re-occur frequently In this paper, we suggest a technique of selecting an IVCircle(Interior Validity Circle) in a Skyline Region as the static Safe Region using the characteristics of the OSR. An Interior IVCircle can be calculated in advance when the OSR is decided. Our experiment shows that the frequency of using IVcircle as safe region reduced than that of using VCircle as safe region by 52.55%.

• The KIPS Transactions:PartD
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• v.17D no.4
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• pp.245-252
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• 2010

In this paper, we propose an effective filtering method for skyline queries in mobile ad hoc networks (MANETs). Most existing researches assume that data is uniformly distributed. Under these assumptions, the previous works focus on optimizing the energy consumption due to the limited battery power. However, in practice, data distribution is skewed in a specific region. In order to reduce the energy consumption, we propose a new filtering method considering the data distribution. We verify the performance of the proposed method through a comparative experiment with an existing method. The results of the experiment confirm that the proposed method reduces the communication overhead and execution time compared to an existing method.

• The Journal of Korean Association of Computer Education
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• v.18 no.5
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• pp.63-70
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• 2015

In the environment that the complex conditions need to be satisfied, skyline query have been applied to various field. To processing a skyline query in centralized scheme, several techniques have been suggested and recently map/reduce platform based approaches has been proposed which divides data space into multiple partitions for the vast volume of multidimensional data. However, the performances of these approaches are fluctuated due to the uneven data loading between servers and redundant tasks. Motivated by these issues, this paper suggests a novel technique called MR-DEAP which solves the uneven data loading using the random sampling. The experimental result gains the proposed MR-DEAP outperforms MR-Angular and MR-BNL scheme.

• Magazine of RCR
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• v.17 no.1
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• pp.22-27
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• 2022

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.35-36
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• 2015

본 논문에서는 모바일 P2P 네트워크에서 스카이라인 질의 처리를 위한 새로운 필터링 기법을 제안한다. 제안하는 기법에서는 질의처리 이전에 스카이라인 처리를 통해 필터링 객체 셋을 생성하기 위해 피어 간 데이터 배포를 수행한다. 생성된 필터링 객체를 활용하여 질의에 참여하는 객체 중 불필요한 객체를 필터링한다. 사전 스카이라인 처리를 통해 효율적인 질의처리를 수행할 수 있다.

• Digital Contents
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• no.2 s.93
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• pp.76-81
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• 2001

하루가 다르게 서울의 스카이라인이 바뀌고 있다. 수도 서울의 발전과 변화는 그만큼 정치, 경제, 문화, 사회가 성숙되어 가고 있다는 반증일 뿐 아니라 우리의 비전마저 읽게 한다. 서울의 스카이라인이 바뀌고 있다는 얘기는 어제 오늘의 일이 아니지만 역시 정책 당국자의 미래지향적 정책 운영을 가늠케 한다.