• Title/Summary/Keyword: 공집합

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A Concept of Multi-Layered Database for the Maintenance and Management of Bridges (교량의 유지관리를 위한 멀티레이어 데이터베이스 개념)

  • Kim, Bong-Geun;Yi, Jin-Hoon;Lee, Sang-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.3
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    • pp.393-404
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    • 2007
  • A concept of multi-layered database is proposed for the integrated operation of bridge information in this study. The multi-layered database is a logically integrated database composed of standardized information layers. The standardized information layers represent the data sets that can be unified, and they are defined by standardized information models. Classification system of bridge component was used as a basis of the multi-layered database, and code system based on the classification system was employed as a key integrator to manipulate the distributed data located on the different information layers. In addition, data level indicating priorities of information layers was defined to support strategic planning of the multi-layered database construction. As a proof of concept, a prototype of multi-layered database for object-oriented 3-D shape information and structural calculation document was built. Data consistency check of the semantically same data in the two different information layer was demonstrated, It is expected that the proposed concept can assure the integrity and consistency of information in the bridge information management.

Color halftoning based on color correction using vector error diffusion (벡터 오차 확산법을 이용한 색보정 기반의 칼라 중간조 처리법)

  • Choi, Woen-Hee;Lee, Cheol-Hee;Kim, Jeong-Yeop;Kim, Hee-Soo;Ha, Yeong-Ho
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.37 no.5
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    • pp.76-83
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    • 2000
  • This paper proposes a new color halftorning method using color correction by vector error diffusion to reduce color difference, necessarily appears on cross-media color reproduction In order to predict output colors on each device, a neural system IS applied and mean prediction errors in device characterization for monitor and printer are defined to calculate the thresholds for color correction Thus, color difference between monitor and printer is compared per each pixel If color difference is larger than the predetermined mean prediction errors, the halftoned dots to the current pixel are rearranged by vector error diffusion The proposed method can reduce the smear artifact by selective vector error diffusion and decrease color difference on cross- media color reproduction by color correction.

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Efficient Processing of Multidimensional Vessel USN Stream Data using Clustering Hash Table (클러스터링 해쉬 테이블을 이용한 다차원 선박 USN 스트림 데이터의 효율적인 처리)

  • Song, Byoung-Ho;Oh, Il-Whan;Lee, Seong-Ro
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.47 no.6
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    • pp.137-145
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    • 2010
  • Digital vessel have to accurate and efficient mange the digital data from various sensors in the digital vessel. But, In sensor network, it is difficult to transmit and analyze the entire stream data depending on limited networks, power and processor. Therefore it is suitable to use alternative stream data processing after classifying the continuous stream data. In this paper, We propose efficient processing method that arrange some sensors (temperature, humidity, lighting, voice) and process query based on sliding window for efficient input stream and pre-clustering using multiple Support Vector Machine(SVM) algorithm and manage hash table to summarized information. Processing performance improve as store and search and memory using hash table and usage reduced so maintain hash table in memory. We obtained to efficient result that accuracy rate and processing performance of proposal method using 35,912 data sets.

Loadbalancing for WDM Network using Dynamic Watermarks (WDM 네트워크에서 동적 워터마크 결정을 이용한 로드벨런싱)

  • Nahm, Jung-Joo;Kim, Sung-Chun
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.2
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    • pp.1-5
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    • 2007
  • Wavelength-division multiplexed (WDM) networks are emerging to be the right choice for the future transport networks. In WDM networks, the optical layer provides circuit-switched lightpath services to the client layer such as IP, SONET and ATM. The set of lightpaths in the optical layer defines the virtual topology. Since the optical switches are reconfigurable, the virtual topology can be reconfigured in accordance with the changing traffic demand pattern at theclient layer in order to optimize the network performance. We present a new approach to the virtual topology reconfiguration and loadbalancing problem for wavelength-routed, optical wide-area networks under dynamic traffic demand. By utilizing the measured Internet backbone traffic characteristics, our approach follows the changes in traffic without assuming that the future traffic pattern is known. For the simulation traffic modeling, we collected the data from real backbone traffic. Experiments show that the standard deviation compared to previous technique is reduced.

Ternary Bloom Filter Improving Counting Bloom Filter (카운팅 블룸필터를 개선하는 터너리 블룸필터)

  • Byun, Hayoung;Lee, Jungwon;Lim, Hyesook
    • Journal of the Institute of Electronics and Information Engineers
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    • v.54 no.1
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    • pp.3-10
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    • 2017
  • Counting Bloom filters (CBFs) have been popularly used in many network algorithms and applications for the membership queries of dynamic sets, since CBFs can provide delete operations, which are not provided in a standard 1-bit vector Bloom filter. However, because of the counting functions, a CBF can have overflows and accordingly false negatives. CBFs composed of 4-bit counters are generally used, but the 4-bit CBF wastes memory spaces by allocating 4 bits for every counter. In this paper, we propose a simple alternative of a 4-bit CBF named ternary Bloom filter (TBF). In the proposed TBF structure, if two or more elements are mapped to a counter in programming, the counters are not used for insertion or deletion operations any more. When the TBF consumes the same amount of memory space as a 4-bit CBF, it is shown through simulation that the TBF provides a better false positive rate than the CBF as well as the TBF does not generate false negatives.

Texture Evolution during Primary Recrystallization and Effect of Number of Cold Rolling Passes, Heating Rate, and Si Contents in Grain-Oriented Electrical Steel (방향성 전기강판에서 1차 재결정시 Si 함량과 냉간압연 횟수, 승온 속도에 따른 집합조직 발달)

  • Jeon, Soeng-Ho;Park, No Jin
    • Journal of the Korean Society for Heat Treatment
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    • v.31 no.6
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    • pp.269-274
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    • 2018
  • Grain-oriented electrical steel sheets are mainly used as core materials for transformers and motors. They should have excellent magnetic properties such as low core loss, high magnetic flux density and high permeability. In order to improve the magnetic properties of the electrical steel sheet, it is important to form Goss oriented grains with a very strong {110}<001> orientation. Recently, efforts have been made to develop Goss grains by controlling processes such as hot rolling, cold rolling, and primary and secondary recrystallization. In this study, the sheets containing 3.2 and 3.4wt.% Si were used, which were rolled with 1 and 10 passes with total thickness reduction of 89%. Heating was carried out for primary recrystallization with different heating rates of $25^{\circ}C/s$ and $24^{\circ}C/min$ until $720^{\circ}C$. The behavior of Goss-, {411}<148>-, and {111}<112>-oriented grains were analyzed using X-ray diffraction(XRD) and electron back-scatter diffraction(EBSD) analysis. The area fraction of Goss-oriented grains increased with the number of rolling passes during cold rolling; however, after the primary recrystallization, the area fraction of the Goss grains was higher and exact Goss grains were found in the specimens subjected to rapid heating after one rolling pass.

Effect of Cross Rolling on the Development of Textures in Tantalum (탄탈륨 집합조직 발달에 대한 교차압연의 영향)

  • Kang, Jun-Yun;Park, Seongwon;Park, Jun Young;Park, Seong-Jun;Song, Yi-Hwa;Park, Sung-Taek;Kim, Gwang-Lyeon;Oh, Kyeong-Won
    • Journal of the Korean Society for Heat Treatment
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    • v.31 no.6
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    • pp.275-282
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    • 2018
  • Two different modes of rolling were applied to control the texture development in tantalum sheet. In the conventional uni-directional rolling, the typical rolling textures of a body-centered cubic metal which was primarily composed of <110>//(rolling direction) was developed. In a cross rolling where the specimen was rotated by $90^{\circ}$ between each pass, the rotated cube components, i.e. {100}<011> were greatly reinforced. The prediction of lattice rotation by the full-constraint Taylor model showed that the high stability and the symmetry of the rotated cube components caused their strengthening in cross-rolling. The two specimens were heated to $1,100^{\circ}C$ at $9^{\circ}C/min$and held for 1 hour for annealing, then cooled to room temperature in atmosphere. In spite of the significant difference in the deformation textures, the annealing textures were very similar. They developed strong <111>//(plane normal) components with negligible intensity at the rotated cube components, which was attributed to the negligible capability of the latter components to provide effective recrystallized grains.

Robust Outlier-Object Detection in Image Pairs Based on Variable Threshold Using Empirical Correction Constant (실험적 교정상수를 사용한 가변문턱값에 기초한 영상 쌍에서의 강인한 이상 물체 검출)

  • Kim, Dong-Sik
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.46 no.1
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    • pp.14-22
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    • 2009
  • By calculating the differences between two images, which are captured with the same scene at different time, we can detect a set of outliers, such as occluding objects due to moving vehicles. To reduce the influence from the different intensity properties of the images, a simple technique that reruns the regression, which is based on the polynomial regression model, is employed. For a robust detection of outliers, the image difference is normalized by the noise variance. Hence, an accurate estimate of the noise variance is very important. In this paper, using an empirically obtained correction constant is proposed. Numerical analysis using both synthetic and real images are also shown in this paper to show the robust performance of the detection algorithm.

Performance of PPSM System in multipath channel for UWB Communication (다중경로 환경을 고려한 PPSM 임펄스 시스템의 성능 분석)

  • Park Ho-Hwan;Kim Jin-Su;Hwang Hyeon-Chyeol;Kwak Kyung-Sup
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.43 no.2 s.344
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    • pp.7-15
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    • 2006
  • Recently, Ultra-wideband (UWB) Communication systems have become a popular research topic. UWB system is characterized by the fact that the digital information represented by a subnanosecond pulses is transmitted through the air. In this paper, we consider the PPSM scheme that combine PPM and PSM. We provide the performance in AWGN and SV multipath channel which consists of $CM1\~CM4$. The optimal symbol set for M-ary system in multipath channel which shows good performance is also presented. The simulation results show that the performance in CM4 is worse than that in CMI due to long delay spread, many multipath components, 4-ary system outperforms binary system in Low$E_b/N_0$ but not in high $E_b/N_0$. We find system have the optimal symbol set in multipath channel.

Study on the Fuzzy Inference System for Objectivity of Ground Evaluation in Tunnelling (터널지반 평가의 객관화를 위한 퍼지추론시스템 연구)

  • 조만섭;김영석
    • Tunnel and Underground Space
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    • v.13 no.1
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    • pp.6-19
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    • 2003
  • This study has for its object to increase an objectivity of the observation result in the face mapping of tunnel and to suggest the reasonable support and reinforcement methods to be considered the rock properties. It was developed in this study to the tunnel stability evaluation system(Prototype NFEST) to be used fuzzy set theory and neuro-fuzzy techniques, and this system was verified according to the reliability evaluation between the 36 learning data and the inferred results. When it summarized the results; (1) 12 evaluation items and ranges were proposed to be modified basis on the RMR which are well known to the domestic workers. (2) It was shown that correlation coefficient(│R│) between $RMR_{inf}$ inferred by 12 items and $RMR_{org}$ due to arithmetic total, $RMR_{chk}$ due to subjective judgement of observer are relatively high relationship with each 0.83 and 0.79. (3) Inferred result of the total tunnel safety shows also a good relationship with $RMR_{inf}$ (│R│=0.7) and the rock weathering(│R│=0.84).