5,217,411 research outputs found
Effect of GPa pressure on microstructures and heat transfer phenomena of aluminum alloys during solidification
No full text학위논문(박사) - 한국과학기술원 : 재료공학과, 1994.8, [ iv, 116 p. ]한국과학기술원 : 재료공학과
Do Bugs Propagate? An Empirical Analysis of Temporal Correlations Among Software Bugs
Get PDFThe occurrences of bugs are not isolated events, rather they may interact, affect each other, and trigger other latent bugs. Identifying and understanding bug correlations could help developers localize bug origins, predict potential bugs, and design better architectures of software artifacts to prevent bug affection. Many studies in the defect prediction and fault localization literature implied the dependence and interactions between multiple bugs, but few of them explicitly investigate the correlations of bugs across time steps and how bugs affect each other. In this paper, we perform social network analysis on the temporal correlations between bugs across time steps on software artifact ties, i.e., software graphs. Adopted from the correlation analysis methodology in social networks, we construct software graphs of three artifact ties such as function calls and type hierarchy and then perform longitudinal logistic regressions of time-lag bug correlations on these graphs. Our experiments on four open-source projects suggest that bugs can propagate as observed on certain artifact tie graphs. Based on our findings, we propose a hybrid artifact tie graph, a synthesis of a few well-known software graphs, that exhibits a higher degree of bug propagation. Our findings shed light on research for better bug prediction and localization models and help developers to perform maintenance actions to prevent consequential bugs
Simon’s Congruence Pattern Matching
Get PDFTesting Simon’s congruence asks whether two strings have the same set of subsequences of length no greater than a given integer. In the light of the recent discovery of an optimal linear algorithm for testing Simon’s congruence, we solve the Simon’s congruence pattern matching problem. The problem requires finding all substrings of a text that are congruent to a pattern under the Simon’s congruence. Our algorithm efficiently solves the problem in linear time in the length of the text by reusing results from previous computations with the help of new data structures called X-trees and Y-trees. Moreover, we define and solve variants of the Simon’s congruence pattern matching problem. They require finding the longest and shortest substring of the text as well as the shortest subsequence of the text which is congruent to the pattern under the Simon’s congruence. Two more variants which ask for the longest congruent subsequence of the text and optimizing the pattern matching problem are left as open problems
Kim Yo Han
No full text학위논문(석사)--아주대학교 정보통신대학원 :정보보호,2009. 2요 약 문
현 경계작전은 쌍안경, 야간감시경, 발성장애물 등 감시보조장비와 제한된 과학화 장비를 이용하여 실시되고 있으나, 대부분 인간의 오감에 의한 감시로 탐지의 신뢰성이 낮아 시·공간적 사각지역을 극복할 수 있는 대책이 필요하다. 따라서 본 연구에서는 RFID/USN 기술을 이용한 무인감시 시스템 구축 시 군사용으로 사용할 수 있도록 센서노드와 M/W, 보안 분야에 대한 요구사항을 도출하였다.차 례
제1장. 서 론 1
제2장. 국방 무인감시 시스템 3
2.1 고정형 시스템 4
2.2 이동형 시스템 6
2.3 센서노드의 유형별 특성 7
2.4 USN장비의 논리적 구조 9
2.4.1 센서노드 9
2.4.2 중계노드 11
2.4.3 고정형 싱크노드 12
2.4.4 이동형 싱크노드 14
제3장. 시스템 요구사항 분석 16
3.1 센서노드에 대한 요구사항 16
3.1.1 센서들의 오경보 최소화 16
3.1.2 센서노드의 위장 17
3.1.3 USN장비의 피탈 대응 18
3.1.4 주파수 잠식에 의한 센서장비들의 오작동 19
3.2 미들웨어(M/W)에 대한 요구사항 20
3.2.1 신뢰성 있는 상황도 도시 방안 20
3.2.2 장비 / 네트워크 운영 23
3.3 보안 요구사항 24
3.3.1 무인감시체계의 취약점 25
3.3.2 RFID / USN 공격 기법 27
3.3.3 무인감시체계 보안 목표 29
제4장. 결 론 32
참 고 문 헌 33Maste
Yo-Yo intermittent recovery test (Yo-Yo test): valores normativos para jogadores de futebol das categorias sub-13, sub-15, sub-17 e sub-20
No full textObjetivo: Propor valores referenciais, classificados em percentuais, do instrumento Yo-Yo test para jogadores de futebol das categorias Sub-13, Sub-15, Sub-17 e Sub-20.
Métodos: Estudo longitudinal, compreendendo os anos de 2006 a 2014 (exceto 2008), com jogadores das categorias masculinas Sub-13, Sub-15, Sub-17 e Sub-20 do Fluminense Football Club. O Yo-Yo test foi realizado duas vezes por ano com todos os jogadores, incluindo goleiros, compreendendo pré-temporada e período competitivo; executado nos horários de treinamento das categorias, no campo gramado e com chuteiras. O teste ANOVA one-way foi utilizado para comparar o VO2max entre as categorias. Para a construção da tabela de valores normativos do VO2max utilizando o teste Yo-Yo, foi usado o cálculo de porcentagem em cada categoria analisada.
Resultados: O percentil do VO2MAX estimado pelo teste Yo-Yo para a categoria Sub-13 (n=259) foi de 50,0 mL.(kg.min)-1; para a Sub-15 (n=959), de 53,4 mL.(kg.min)-1; para a Sub-17 (n = 753), de 55,9 mL.(kg.min)-1; e para a Sub-20 (n = 531), de 56,9 mL.(kg.min)-1. Foi possível propor uma tabela de classificação do VO2max ml(kg.min)-1 em cinco categorias já que a idade foi um fator determinante em seu comportamento.
Conclusão: A idade tem influência na capacidade aeróbia em categorias diferentes em um time de futebol, exigindo a construção de tabelas normativas específicas. O Sub-20 apresenta valores de VO2max compatíveis com os de profissionais. Os valores apresentados, através de percentuais, podem servir de referência para fundamentar a detecção de talentos, acompanhamento do efeito do treinamento, orientação da prescrição de exercícios, prática clínica
Development, uptake, and wider applicability of the Yo-yo strategy in biology education research: A reappraisal.
No full textHeredity is a biological phenomenon that manifests itself on different levels of biological organization. The yo-yo learning and teaching strategy, which draws on the hierarchy of life, has been developed to tackle the macro-micro problem and to foster coherent understanding of genetic phenomena. Its wider applicability was suggested and since then yo-yo learning seems to be noticed in the biology education research community. The aim of this paper is to reappraise yo-yo thinking in biology education research based on its uptake and any well-considered adaptations by other researchers in the past fifteen years. Based on a literature search we identified research that explicitly and substantially build on the characteristics of yo-yo thinking. Seven questions guided the analysis of chosen cases focussing on how key concepts are matched to levels of biological organization, interrelated, and embedded in a pattern of explanatory reasoning. The analysis revealed that yo-yo thinking as a heuristic of systems thinking has been an inspiring idea to promote coherent conceptual understanding of various biological phenomena. Although, selective use has been made of the yo-yo strategy, the strategy was also further elaborated to include the molecular level. Its functioning as a meta-cognitive tool requires more specification, and teachers’ perceptions and experiences regarding yo-yo thinking should be addressed in future studies. View Full-Tex
Seasonal changes in anthropometric and physical characteristics within English academy rugby league players.
Get PDFProfessional rugby league clubs implement training programmes for the development of anthropometric and physical characteristics within an academy programme. However, research that examines seasonal changes in these characteristics is limited. The purpose of the study was to evaluate the seasonal changes in anthropometric and physical characteristics of academy rugby league players by age category (i.e., under 14, 16, 18, 20). Data were collected on 75 players pre- and postseason over a 6-year period (resulting in a total of 195 assessments). Anthropometric (body mass, sum of 4 skinfolds) and physical (10- and 20-m sprint, vertical jump, Yo-Yo intermittent recovery test and 1 repetition maximum squat, bench press, and prone row) measures were collected. The under 14s and 16s showed greater seasonal improvements in body mass (e.g., under 14s = 7.4 ± 4.3% vs. under 20s = 1.2 ± 3.3%) and vertical jump performance than under 18s and under 20s. In contrast, under 18s and under 20s players showed greater seasonal improvements in Yo-Yo performance and 10-m sprint (e.g., under 14s = 1.3 ± 3.9% vs. under 20s = -1.9 ± 1.2%) in comparison to under 14s and under 16s. Seasonal strength improvements were greater for the under 18s compared with under 20s. This study provides comparative data for seasonal changes in anthropometric and physical characteristics within rugby league players aged 13-20 years. Coaches should be aware that seasonal improvements in speed may not exist within younger age categories, until changes in body mass stabilize and consider monitoring changes in other characteristics (e.g., momentum). Large interplayer variability suggests that player development should be considered on an individual and longitudinal basis
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