• Title/Summary/Keyword: Evaluation criterion

Search Result 964, Processing Time 0.027 seconds

Strength Evaluation of Friction Welded SUH35/SUB3 Considering Stress Singularity (응력특이성을 고려한 SUH35/SUH3 마찰용접재의 강도평가)

  • Chung, Nam-Yong;Park, Chul-Hee
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.14 no.4
    • /
    • pp.59-67
    • /
    • 2006
  • Recently, application of friction welded SUH35/SUH3 is increasing in the manufacturing process of automotive engine valves For securing its reliability and a reasonable strength evaluation method, it is necessary to assess stress singularity under the residual stress condition on the friction welded interface between dissimilar materials. In this paper, strength evaluation method of friction welded materials was investigated by boundary element method and static tensile testing. An advanced method of quantitative strength evaluation for SUH35/SUH3 friction welded material is to be suggested by establishing fracture criterion by using stress singularity factors.

Psycho-acoustic evaluation of the indoor noise in cabins of a naval vessel using a back-propagation neural network algorithm

  • Han, Hyung-Suk
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • v.4 no.4
    • /
    • pp.374-385
    • /
    • 2012
  • The indoor noise of a ship is usually determined using the A-weighted sound pressure level. However, in order to better understand this phenomenon, evaluation parameters that more accurately reflect the human sense of hearing are required. To find the level of the satisfaction index of the noise inside a naval vessel such as "Loudness" and "Annoyance", psycho-acoustic evaluation of various sound recordings from the naval vessel was performed in a laboratory. The objective of this paper is to develop a single index of "Loudness" and "Annoyance" for noise inside a naval vessel according to a psycho-acoustic evaluation by using psychological responses such as Noise Rating (NR), Noise Criterion (NC), Room Criterion (RC), Preferred Speech Interference Level (PSIL) and loudness level. Additionally, in order to determine a single index of satisfaction for noise such as "Loudness" and "Annoyance", with respect to a human's sense of hearing, a back-propagation neural network is applied.

A Study of Hospital Job Evaluation based on Criterion for High-Risk Musculoskeletal Disorders (근골격계 부담작업 기준을 이용한 병원 작업에 대한 평가)

  • Park, Dong-Hyun;Choi, Soon-Young
    • Journal of the Korea Safety Management & Science
    • /
    • v.13 no.4
    • /
    • pp.91-100
    • /
    • 2011
  • Main motivation for this study was to identify the relationship between high-risk hospital jobs and their symptoms associated. This study has three objectives; 1) Evaluate major jobs of hospital workers based on Criterion(Notification number 2003-24 from Ministry of Labor in Korea) for high-risk musculoskeletal disorders(MSDs), 2) Relate each jobs in criterion and the hospital jobs considered in this study, 3) Relate each jobs in criterion and MSDs symptoms of hospital workers. A total 141 hospital jobs was evaluated. Specifically, a total 688 hospital workers participated in the questionnaire survey in this study. There were two most jobs belonged to the numbers 2 and 4 from criterion. Most hospital workers participated in this study thought that the numbers 1 and 2 from criterion were associated with their jobs. In terms of MSDs symptoms, the numbers 1 and 2 from criterion were associated with their jobs as well. Further study for hospital jobs should be focused on breaking down quantification levels of each numbers in the criterion due to its atypical and non-repetitive job characteristics of hospital jobs.

Fracture criterion of mixed mode in adhesively bonded joints of Al/Steel dissimilar materials (Al/Steel 이종재료의 접착이음에 대한 혼합모드의 파괴기준)

  • Jeong, Nam-Yong;Jang, Jin-Mo
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.21 no.8
    • /
    • pp.1322-1331
    • /
    • 1997
  • A method of strength evaluation applying fracture mechanics in the adhesively bonded joints of Al/Steel dissimilar materials was investigated in this paper. Various shapes of adhesively bonded Al/Steel scarf joints focussing on fracture criterion of mixed mode crack were prepared for the static tests. Also, stress intensity factors of the interface cracks in adhesively bonded joints of Al/Steel dissimilar materials were analyzed with 2-dimensional elastic program of boundary element method(BEM), and the experiment of fracture toughness were carried out under various mixed mode conditions. From the results, the fracture criterion and method of strength evaluation by the fracture toughness in adhesively bonded joints of Al/Steel dissimilar materials were proposed.

Analysis of Fracture Surface and Fracture Criterion of Mixed Mode is $Si_{3}N_{4}$ Metal Bonded Joints (질화규소/금속 접합재에 대한 혼합모드의 파괴기준 및 파면해석)

  • 정남용
    • Journal of the Korean Society of Manufacturing Technology Engineers
    • /
    • v.8 no.2
    • /
    • pp.86-93
    • /
    • 1999
  • Ceramic/metal bonded joints have led to increasing use of structural materials such as automobiles and heat engines. A method of strength evaluation focussing on fracture criterion of mixed mode was investigated in {{{{ {Si }_{3 } {N }_{4 } }}}}/metal bonded joint, Also Fracture toughness tests of {{{{ {Si }_{3 } {N }_{4 } }}}}/metal bonded joints with an interface crack were carried out and the stress intensity factors of these joints were analyzed by boundary element method. Form the results the fracture criterion and method of strength evaluation by the fracture toughness were proposed in {{{{ {Si }_{3 } {N }_{4 } }}}}/Metal bonded joints

  • PDF

An Exploratory Study on the Selection Criterion of an Airline Firm (항공사 선택요인 분석)

  • Yoo, Yong-Jae;Lee, Seung-Chang
    • Journal of the Korean Society for Aviation and Aeronautics
    • /
    • v.14 no.4
    • /
    • pp.101-109
    • /
    • 2006
  • This study investigates what criterion airline customers recognize important when evaluating airline firms. Specifically it is surveyed if different criterion are used by different groups of airline customers when choosing an airline firm. In addition customer group with high loyalty to 'K' airline, national carrier of Korea, is differently evaluate 'K' airline for the selection criterion over customer group without loyalty. Frequent flyer program is suggested most important by most of the customers being followed by flight schedule. Flight schedule, in-flight food and air fare of 'K' airline are differently evaluated according to level of royalty to the airline. However there appears no difference in the evaluation of seat and entertainment between two groups, customers with high loyalty and customers without loyalty.

  • PDF

Establishment of Fracture Criterion on Friction Welded Dissimilar Materials (이종 마찰용접재의 파괴기준 설정)

  • Chung, Nam-Yong;Park, Cheol-Hee
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.14 no.5
    • /
    • pp.164-171
    • /
    • 2006
  • Application of friction welding is increasing in the manufacturing process of machine elements in many industry fields. To establish a reasonable strength evaluation method and fracture criterion, it is necessary to analyze stress singularity under the residual stress condition on friction welded interface between dissimilar materials. In this paper, a method to establish fracture criterion on interface of friction welded dissimiliar materials was investigated by using the boundary element method BEM and static tensile testing. A quantitative fracture criterion for friction welded dissimilar materials is suggested by using stress singularity factor, $\Gamma$.

Evaluation of a Simplified Criterion for SSI Analysis (지반-구조물 상호작용 해석의 단순화된 기준에 대한 평가)

  • Kim, Jae-Min;Kim, Won-Hee;Hyun, Chang-Hun
    • Proceedings of the Earthquake Engineering Society of Korea Conference
    • /
    • 2006.03a
    • /
    • pp.337-344
    • /
    • 2006
  • This paper is concerned with the simplified criterion given in ASCE 4-98, for determining whether soil-structure interaction (SSI) analysis is required for seismic response analysis of nuclear power plant structures. In this study, the criterion is evaluated for a couple of example structures including an existing nuclear power plant and the Hualien large-scale seismic test building. Forced vibration analysis and seismic response analysis are carried out using the simple stick model with soil springs and an elaborated SSI analytical model. From the numerical analyses, it is found that the criterion may not allow the fixed-base analysis for bedrock with shear wave velocity of greater than 1,100m/s which is a well-known criterion for a rock site. In addition, it is indicated that peak amplification as well as the peak broadening specified in NRC RG 1.122. shall be considered to include the effects of SSI.

  • PDF

Methodology for Identifying Issues of User Reviews from the Perspective of Evaluation Criteria: Focus on a Hotel Information Site (사용자 리뷰의 평가기준 별 이슈 식별 방법론: 호텔 리뷰 사이트를 중심으로)

  • Byun, Sungho;Lee, Donghoon;Kim, Namgyu
    • Journal of Intelligence and Information Systems
    • /
    • v.22 no.3
    • /
    • pp.23-43
    • /
    • 2016
  • As a result of the growth of Internet data and the rapid development of Internet technology, "big data" analysis has gained prominence as a major approach for evaluating and mining enormous data for various purposes. Especially, in recent years, people tend to share their experiences related to their leisure activities while also reviewing others' inputs concerning their activities. Therefore, by referring to others' leisure activity-related experiences, they are able to gather information that might guarantee them better leisure activities in the future. This phenomenon has appeared throughout many aspects of leisure activities such as movies, traveling, accommodation, and dining. Apart from blogs and social networking sites, many other websites provide a wealth of information related to leisure activities. Most of these websites provide information of each product in various formats depending on different purposes and perspectives. Generally, most of the websites provide the average ratings and detailed reviews of users who actually used products/services, and these ratings and reviews can actually support the decision of potential customers in purchasing the same products/services. However, the existing websites offering information on leisure activities only provide the rating and review based on one stage of a set of evaluation criteria. Therefore, to identify the main issue for each evaluation criterion as well as the characteristics of specific elements comprising each criterion, users have to read a large number of reviews. In particular, as most of the users search for the characteristics of the detailed elements for one or more specific evaluation criteria based on their priorities, they must spend a great deal of time and effort to obtain the desired information by reading more reviews and understanding the contents of such reviews. Although some websites break down the evaluation criteria and direct the user to input their reviews according to different levels of criteria, there exist excessive amounts of input sections that make the whole process inconvenient for the users. Further, problems may arise if a user does not follow the instructions for the input sections or fill in the wrong input sections. Finally, treating the evaluation criteria breakdown as a realistic alternative is difficult, because identifying all the detailed criteria for each evaluation criterion is a challenging task. For example, if a review about a certain hotel has been written, people tend to only write one-stage reviews for various components such as accessibility, rooms, services, or food. These might be the reviews for most frequently asked questions, such as distance between the nearest subway station or condition of the bathroom, but they still lack detailed information for these questions. In addition, in case a breakdown of the evaluation criteria was provided along with various input sections, the user might only fill in the evaluation criterion for accessibility or fill in the wrong information such as information regarding rooms in the evaluation criteria for accessibility. Thus, the reliability of the segmented review will be greatly reduced. In this study, we propose an approach to overcome the limitations of the existing leisure activity information websites, namely, (1) the reliability of reviews for each evaluation criteria and (2) the difficulty of identifying the detailed contents that make up the evaluation criteria. In our proposed methodology, we first identify the review content and construct the lexicon for each evaluation criterion by using the terms that are frequently used for each criterion. Next, the sentences in the review documents containing the terms in the constructed lexicon are decomposed into review units, which are then reconstructed by using the evaluation criteria. Finally, the issues of the constructed review units by evaluation criteria are derived and the summary results are provided. Apart from the derived issues, the review units are also provided. Therefore, this approach aims to help users save on time and effort, because they will only be reading the relevant information they need for each evaluation criterion rather than go through the entire text of review. Our proposed methodology is based on the topic modeling, which is being actively used in text analysis. The review is decomposed into sentence units rather than considering the whole review as a document unit. After being decomposed into individual review units, the review units are reorganized according to each evaluation criterion and then used in the subsequent analysis. This work largely differs from the existing topic modeling-based studies. In this paper, we collected 423 reviews from hotel information websites and decomposed these reviews into 4,860 review units. We then reorganized the review units according to six different evaluation criteria. By applying these review units in our methodology, the analysis results can be introduced, and the utility of proposed methodology can be demonstrated.

Development of the Evaluation Criterion for Mathematically Gifted Students Creative Product in View of Mathematical History (수학사에 근거한 수학영재의 창의적 산출물 평가 준거 개발)

  • Kim Sun Hee
    • Journal for History of Mathematics
    • /
    • v.18 no.2
    • /
    • pp.75-94
    • /
    • 2005
  • This study is intended to develop the criterion for evaluating the creative products that mathematically gifted students produce in their education program to enhance the development of creative productive ability. 1 distinguish the mathematical creativity with the creativity in the general domain, and make the production model of the creative mathematical product grounded on the mathematicians' work through the mathematical history. The model has the following components; the mathematical knowledge, the mathematical thinking and the mathematical inquiry skill, surrounding the resultive creative product. The students products are focused on one component of the model. Thus the criterion for the creative products is grounded on the each component of the model. According to it, teachers could evaluate the students'work, which got the validity and the reliability.

  • PDF