• Title/Summary/Keyword: thresholds

Search Result 1,047, Processing Time 0.021 seconds

ON DIVISORS COMPUTING MLD'S AND LCT'S

  • Blum, Harold
    • Bulletin of the Korean Mathematical Society
    • /
    • v.58 no.1
    • /
    • pp.113-132
    • /
    • 2021
  • We show that if a divisor centered over a point on a smooth surface computes a minimal log discrepancy, then the divisor also computes a log canonical threshold. To prove the result, we study the asymptotic log canonical threshold of the graded sequence of ideals associated to a divisor over a variety. We systematically study this invariant and prove a result describing which divisors compute asymptotic log canonical thresholds.

Risk Assessment for Noncarcinogenic Chemical Effects

  • Kodell Ralph L.
    • 대한예방의학회:학술대회논문집
    • /
    • 1994.02a
    • /
    • pp.412-415
    • /
    • 1994
  • The fundamental assumption that thresholds exist for noncarcinogenic toxic effects of chemicals is reviewed; this assumption forms the basis for the no-observed-effect level/ safety-factor (NOEL/SF) approach to risk assessment for such effects. The origin and evolution of the NOEL/SF approach are traced, and its limitations are discussed. The recently proposed use of dose-response modeling to estimate a benchmark dose as a replacement for the NOEL is explained. The possibility of expanding dose-response modeling of non carcinogenic effects to include the estimation of assumed thresholds is discussed. A new method for conversion of quantitative toxic responses to a probability scale for risk assessment via dose-response modeling is outlined.

  • PDF

A New Buffer Management Scheme using Weighted Dynamic Threshold for QoS Support in Fast Packet Switches with Shared Memories (공유 메모리형 패킷 교환기의 QoS 기능 지원을 위한 가중형 동적 임계치를 이용한 버퍼 관리기법에 관한 연구)

  • Kim Chang-Won;Kim Young-Beom
    • Journal of the Institute of Convergence Signal Processing
    • /
    • v.7 no.3
    • /
    • pp.136-142
    • /
    • 2006
  • Existing buffer management schemes for shared-memory output queueing switches can be classified into two types: In the first type, some constant amount of memory space is guaranteed to each virtual queue using static queue thresholds. The static threshold method (ST) belongs to this type. On the other hand, the second type of approach tries to maximize the buffer utilization in 머 locating buffer memories. The complete sharing (CS) method is classified into this type. In the case of CS, it is very hard to protect regular traffic from mis-behaving traffic flows while in the case of ST the thresholds can not be adjusted according to varying traffic conditions. In this paper, we propose a new buffer management method called weighted dynamic thresholds (WDT) which can process packet flows based on loss priorities for quality-of-service (QoS) functionalities with fairly high memory utilization factors. We verified the performance of the proposed scheme through computer simulations.

  • PDF

Calibrating Thresholds to Improve the Detection Accuracy of Putative Transcription Factor Binding Sites

  • Kim, Young-Jin;Ryu, Gil-Mi;Park, Chan;Kim, Kyu-Won;Oh, Berm-Seok;Kim, Young-Youl;Gu, Man-Bok
    • Genomics & Informatics
    • /
    • v.5 no.4
    • /
    • pp.143-151
    • /
    • 2007
  • To understand the mechanism of transcriptional regulation, it is essential to detect promoters and regulatory elements. Various kinds of methods have been introduced to improve the prediction accuracy of regulatory elements. Since there are few experimentally validated regulatory elements, previous studies have used criteria based solely on the level of scores over background sequences. However, selecting the detection criteria for different prediction methods is not feasible. Here, we studied the calibration of thresholds to improve regulatory element prediction. We predicted a regulatory element using MATCH, which is a powerful tool for transcription factor binding site (TFBS) detection. To increase the prediction accuracy, we used a regulatory potential (RP) score measuring the similarity of patterns in alignments to those in known regulatory regions. Next, we calibrated the thresholds to find relevant scores, increasing the true positives while decreasing possible false positives. By applying various thresholds, we compared predicted regulatory elements with validated regulatory elements from the Open Regulatory Annotation (ORegAnno) database. The predicted regulators by the selected threshold were validated through enrichment analysis of muscle-specific gene sets from the Tissue-Specific Transcripts and Genes (T-STAG) database. We found 14 known muscle-specific regulators with a less than a 5% false discovery rate (FDR) in a single TFBS analysis, as well as known transcription factor combinations in our combinatorial TFBS analysis.

Standardization for basic association measures in association rule mining (연관 규칙 마이닝에서의 평가기준 표준화 방안)

  • Park, Hee-Chang
    • Journal of the Korean Data and Information Science Society
    • /
    • v.21 no.5
    • /
    • pp.891-899
    • /
    • 2010
  • Association rule is the technique to represent the relationship between two or more items by numerical representing for the relevance of each item in vast amounts of databases, and is most being used in data mining. The basic thresholds for association rule are support, confidence, and lift. these are used to generate the association rules. We need standardization of lift because the range of lift value is different from that of support and confidence. And also we need standardization of support and confidence to compare objectively association level of antecedent variables for one descendant variable. In this paper we propose a method for standardization of association thresholds considering marginal probability for each item to grasp objectively and exactly association level, check the conditions for association criteria and then compare association thresholds with standardized association thresholds using some concrete examples.

Multi-level Thresholding using Fuzzy Clustering Algorithm in Local Entropy-based Transition Region (지역적 엔트로피 기반 전이 영역에서 퍼지 클러스터링 알고리즘을 이용한 Multi-Level Thresholding)

  • Oh, Jun-Taek;Kim, Bo-Ram;Kim, Wook-Hyun
    • The KIPS Transactions:PartB
    • /
    • v.12B no.5 s.101
    • /
    • pp.587-594
    • /
    • 2005
  • This paper proposes a multi-level thresholding method for image segmentation using fuzzy clustering algorithm in transition region. Most of threshold-based image segmentation methods determine thresholds based on the histogram distribution of a given image. Therefore, the methods have difficulty in determining thresholds for real-image, which has a complex and undistinguished distribution, and demand much computational time and memory size. To solve these problems, we determine thresholds for real-image using fuzzy clustering algorithm after extracting transition region consisting of essential and important components in image. Transition region is extracted based on Inか entropy, which is robust to noise and is well-known as a tool that describes image information. And fuzzy clustering algorithm can determine optimal thresholds for real-image and be easily extended to multi-level thresholding. The experimental results demonstrate the effectiveness of the proposed method for performance.

The Effects of Hold-relax Techniques after Inducing Delayed Muscle Pain on the Pain and Range of Motion of Joints (지연성 근육통 유발 후 유지-이완 기법이 통증과 관절가동범위에 미치는 영향)

  • Kim, Ji-Seon;Woo, Young-Keun;Ki, Kyong-Il
    • PNF and Movement
    • /
    • v.14 no.1
    • /
    • pp.15-21
    • /
    • 2016
  • Purpose: The purpose of the present study was to compare the effects of both general hold-relax techniques and hold-relax techniques using pumping on pain due to delayed muscle pain and on the range of motion (ROM) of joints. Methods: Thirty-nine young adult males and females were randomly assigned either to a hold-relax technique application group of 20 subjects or to a group of 19 subjects with hold-relax techniques applied using a pumping application. Tenderness thresholds, the ROM of joints, and pain intensities were measured on the biceps of the nondominant arm of the subjects in both groups before exercises were performed to induce delayed muscle pain. Tenderness thresholds were again measured 24hours, 48hours, and 72 hours after inducing delayed muscle pain. The relevant intervention methods were applied to the two groups after conducting the measurement at 48hours. As a statistical analysis method, repeated measure ANOVAs were conducted to examine the tenderness thresholds, ROMs of elbow joints, and pain intensities in the individual groups at the time points. Results: At 48 hours and 72 hours after application of the interventions, the general hold-relax technique application group showed greater changes in the tenderness thresholds, the ROMs of elbow joints, and the pain intensities than did the group applying hold-relax techniques using a pumping application (p>0.05). Conclusion: Based on the results of the present study, the application of hold-relax techniques is thought to have beneficial effects on pain resulting from delayed muscle pain and on limited ROMs of joints.

Analysis on Inundation Characteristics for Flood Impact Forecasting in Gangnam Drainage Basin (강남지역 홍수영향예보를 위한 침수특성 분석)

  • Lee, Byong-Ju
    • Atmosphere
    • /
    • v.27 no.2
    • /
    • pp.189-197
    • /
    • 2017
  • Progressing from weather forecasts and warnings to multi-hazard impact-based forecast and warning services represents a paradigm shift in service delivery. Urban flooding is a typical meteorological disaster. This study proposes support plan for urban flooding impact-based forecast by providing inundation risk matrix. To achieve this goal, we first configured storm sewer management model (SWMM) to analyze 1D pipe networks and then grid based inundation analysis model (GIAM) to analyze 2D inundation depth over the Gangnam drainage area with $7.4km^2$. The accuracy of the simulated inundation results for heavy rainfall in 2010 and 2011 are 0.61 and 0.57 in POD index, respectively. 20 inundation scenarios responding on rainfall scenarios with 10~200 mm interval are produced for 60 and 120 minutes of rainfall duration. When the inundation damage thresholds are defined as pre-occurrence stage, occurrence stage to $0.01km^2$, 0.01 to $0.1km^2$, and $0.1km^2$ or more in area with a depth of 0.5 m or more, rainfall thresholds responding on each inundation damage threshold results in: 0 to 20 mm, 20 to 50 mm, 50 to 80 mm, and 80 mm or more in the rainfall duration 60 minutes and 0 to 30 mm, 30 to 70 mm, 70 to 110 mm, and 110 mm or more in the rainfall duration 120 minutes. Rainfall thresholds as a trigger of urban inundation damage can be used to form an inundation risk matrix. It is expected to be used for urban flood impact forecasting.