• Title/Summary/Keyword: Performance Evaluations

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Effects of Different Levels of Concentrate in the Diet on Physicochemical Traits of Korean Native Black Goat Meats

  • Kim, Sang Woo;Park, Seong Bok;Kim, Myeong Jik;Kim, Dong Hun;Yim, Dong-Gyun
    • Food Science of Animal Resources
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    • v.34 no.4
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    • pp.457-463
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    • 2014
  • The effects of feeding of diets based on roughage supplemented with concentrate on the carcass and meat quality attributes of Korean black goats were investigated. The 40 male goats at 5 mon age were divided into four treatment groups; T1 (1.5%), T2 (2.0%), T3 (2.5%) and T4 (ad libitum) feeding of concentrate with ad libitum rice straw. Forty bucks at the end of the feeding were fasted for 12 h before slaughter and were then slaughtered. For carcass measurement, cold buck carcasses were examined after 24 h of chilling at $5^{\circ}C$. The carcasses were chilled in refrigerator at $2{\pm}2^{\circ}C$ for 24 h, then the longissimus dorsi muscle was removed from the carcasses. The samples were separately vacuum packaged, frozen and stored at $-20^{\circ}C$ for up to 1 mon, prior to physicochemical evaluations. Carcass yields were greatly affected by rate of concentrate feeding. T4 showed the heaviest live and carcass weights and the highest dressing and fat percentages (p<0.05). The moisture contents were lower in T4 compared with other treatments, while the crude protein and fat contents were higher (p<0.05). mono-unsaturated fatty acid in T4 was significantly higher than others, which showed the highest percentages of oleic acid (C18:1). For the sensory test, T4 was tenderer and produced better flavor scores than others. Increasing the level of concentrate in the diet resulted in an improvement in growth performance, and carcass and physicochemical characteristics of goat meats.

A WDM/SCM Multiple Access Protocol Using Node Grouping for Passive Double Star Optical Networks (수동이중성형 광통신망에서 노드 그룹핑을 이용한 WDM/SCM 다중접속 프로토콜 설계)

  • Yu, Jin-Tae;Lee, Myeong-Mun;Kim, Yong-Beom;Park, Si-U;Park, Jin-U
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.38 no.9
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    • pp.652-662
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    • 2001
  • A WDM/SCM multiple access protocol suitable for optical double star networks is proposed. A node-grouping scheme is employed in the protocol, which is accomplished by connecting some nodes through passive star sub-hubs forming a group. The resulting multiple groups in a network are then connected through a central passive star hub resulting in a passive double star network. Each group is pre-assigned a WDM channel as its home channel, and SCM channels are used to identify the packet reception at each node. [n the proposed protocol, the average packet delay is remarkably reduced since the frame consists of the number of groups rather than the number of network nodes. Furthermore, additional reduction of the average packet delay is achieved by limiting the propagation paths of control packets to the roundtrip between source nodes and sub-hub using a double star network. It is shown in the performance evaluations using analytic and simulation model that the proposed protocol has the advantages of the higher channel utilization and excellent network throughput and average packet delay characteristic.

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Improved Block-based Background Modeling Using Adaptive Parameter Estimation (적응적 파라미터 추정을 통한 향상된 블록 기반 배경 모델링)

  • Kim, Hanj-Jun;Lee, Young-Hyun;Song, Tae-Yup;Ku, Bon-Hwa;Ko, Han-Seok
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.4
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    • pp.73-81
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    • 2011
  • In this paper, an improved block-based background modeling technique using adaptive parameter estimation that judiciously adjusts the number of model histograms at each frame sequence is proposed. The conventional block-based background modeling method has a fixed number of background model histograms, resulting to false negatives when the image sequence has either rapid illumination changes or swiftly moving objects, and to false positives with motionless objects. In addition, the number of optimal model histogram that changes each type of input image must have found manually. We demonstrate the proposed method is promising through representative performance evaluations including the background modeling in an elevator environment that may have situations with rapid illumination changes, moving objects, and motionless objects.

A Study on Degradation Characteristic of High Strength Fire Resistance Steel for Frame Structure by Acoustic Emission (음향방출법에 의한 고강도 구조용 내화강의 열화특성에 관한 연구)

  • Kim, H.S.;Kang, C.Y.;Nam, K.W.;Kim, B.A.
    • Journal of the Korean Society for Heat Treatment
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    • v.13 no.5
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    • pp.309-317
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    • 2000
  • Demand for new nondestructive evaluations is growing to detect tensile crack growth behavior to predict long term performance of materials and structure in aggressive environments, especially when they are in non-visible area. Acoustic emission technique is well suited to these problems and has drawn a keen interests because of its dynamic detection ability, extreme sensitivity and location of growing defects. In this study, we investigated the strength of fire resistance steel for frame structure by tensile test after degradation treatment and analysed acoustic emission signals obtained from tensile test with time frequency analysis methods. In the T and TN specimens(under $600^{\circ}C$-10min ) consisting of ferrite and pearlite structure, most of acoustic emission events were produced near yield point, mainly due to the dislocation activities during the deformation. However, B specimen under $600^{\circ}C$-10min had a two peak which was attribute to the presence of martensite phase. The first peak is before yield point and the second after yield point. The sources of second acoustic emission peak were the debonding of martensite-martensite interface and the micro-cracking of brittle martensite phase. In $600^{\circ}C$-30min to $700^{\circ}C$-60min, many signals were observed before yield point and were decreased after yield point.

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Self-organization Scheme of WSNs with Mobile Sensors and Mobile Multiple Sinks for Big Data Computing

  • Shin, Ahreum;Ryoo, Intae;Kim, Seokhoon
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.14 no.3
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    • pp.943-961
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    • 2020
  • With the advent of IoT technology and Big Data computing, the importance of WSNs (Wireless Sensor Networks) has been on the rise. For energy-efficient and collection-efficient delivery of any sensed data, lots of novel wireless medium access control (MAC) protocols have been proposed and these MAC schemes are the basis of many IoT systems that leads the upcoming fourth industrial revolution. WSNs play a very important role in collecting Big Data from various IoT sensors. Also, due to the limited amount of battery driving the sensors, energy-saving MAC technologies have been recently studied. In addition, as new IoT technologies for Big Data computing emerge to meet different needs, both sensors and sinks need to be mobile. To guarantee stability of WSNs with dynamic topologies as well as frequent physical changes, the existing MAC schemes must be tuned for better adapting to the new WSN environment which includes energy-efficiency and collection-efficiency of sensors, coverage of WSNs and data collecting methods of sinks. To address these issues, in this paper, a self-organization scheme for mobile sensor networks with mobile multiple sinks has been proposed and verified to adapt both mobile sensors and multiple sinks to 3-dimensional group management MAC protocol. Performance evaluations show that the proposed scheme outperforms the previous schemes in terms of the various usage cases. Therefore, the proposed self-organization scheme might be adaptable for various computing and networking environments with big data.

An Ultra-precision Lathe for Large-area Micro-structured Roll Molds (대면적 미세패턴 롤 금형 가공용 초정밀 롤 선반 개발)

  • Oh, Jeong Seok;Song, Chang Kyu;Hwang, Jooho;Shim, Jong Youp;Park, Chun Hong
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.12
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    • pp.1303-1312
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    • 2013
  • We report an ultra-precision lathe designed to machine micron-scale features on a large-area roll mold. The lathe can machine rolls up to 600 mm in diameter and 2,500 mm in length. All axes use hydrostatic oil bearings to exploit the high-precision, stiffness, and damping characteristics. The headstock spindle and rotary tooling table are driven by frameless direct drive motors, while coreless linear motors are used for the two linear axes. Finite element method modeling reveals that the effects of structural deformation on the machining accuracy are less than $1{\mu}m$. The results of thermal testing show that the maximum temperature rise at the spindle outer surface is approximately $0.5^{\circ}C$. Finally, performance evaluations of the error motion, micro-positioning capability, and fine-pitch machining demonstrate that the lathe is capable of producing optical-quality surfaces with micron-scale patterns with feature sizes as small as $20{\mu}m$ on a large-area roll mold.

A Study on the Evaluation of Tension-Compression Fatigue Characteristics of Glass Fiber/Epoxy 4-Harness Satin Woven Laminate Composite for the Railway Bogie Application (철도차량 대차 적용 유리섬유/에폭시 4-매 주자직 적층 복합재의 인장-압축 피로특성 평가 연구)

  • Jeon, Kwang-Woo;Shin, Kwang-Bok;Kim, Jung-Seok
    • Composites Research
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    • v.23 no.5
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    • pp.22-29
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    • 2010
  • This paper describes the evaluations of tension-compression fatigue characteristics and life for glass fiber/epoxy laminate composite applied to railway bogie to reduce weight. Test samples of tension-compression fatigue were composed of glass fiber/epoxy 4-harness woven laminate composites with different stacking sequence of warp-direction, fill-direction and ${\pm}45^{\circ}$-direction. The tension-compression fatigue test was conducted with stress ratio (R) of -1 and frequency of 5Hz. Goodman diagram were used to evaluate the fatigue characteristics and life of glass fiber/epoxy 4-harness satin woven laminate composite. Anti-buckling jig was designed to prevent buckling of specimen under compression load. The test results showed that the fatigue characteristics of glass fiber/epoxy 4-harness satin woven laminate composite with stacking sequence of warp-direction had a good performance in comparison with that of SM490 used to conventional metal railway bogie.

Item Trend Analysis Considering Social Network Data in Online Shopping Malls (온라인 쇼핑몰에서 소셜 네트워크 데이터를 고려한 상품 트렌드 분석)

  • Park, Soobin;Choi, Dojin;Yoo, Jaesoo;Bok, Kyoungsoo
    • The Journal of the Korea Contents Association
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    • v.20 no.2
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    • pp.96-104
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    • 2020
  • As consumers' consumption activities become more active due to the activation of online shopping malls, companies are conducting item trend analyses to boost sales. The existing item trend analysis methods are analyzed by considering only the activities of users in online shopping mall services, making it difficult to identify trends for new items without purchasing history. In this paper, we propose a trend analysis method that combines data in online shopping mall services and social network data to analyze item trends in users and potential customers in shopping malls. The proposed method uses the user's activity logs for in-service data and utilizes hot topics through word set extraction from social network data set to reflect potential users' interests. Finally, the item trend change is detected over time by utilizing the item index and the number of mentions in the social network. We show the superiority of the proposed method through performance evaluations using social network data.

A study on the optimization of manufacturing processes of double wall bellows for dual fuel engine I - Design optimization by buckling and stress analysis - (Dual Fuel 엔진용 이중관 벨로우즈 제작 공정의 최적화에 관한 연구 I - 좌굴해석 및 응력해석을 통한 설계 최적화 -)

  • Kim, Pyung-Su;Kim, Jong-Do
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.6
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    • pp.499-503
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    • 2016
  • Dual fuel engines are suitable for stricter regulations as they significantly decrease exhaust gas output. Hence, research and development of double wall bellows for dual fuel engines is important. In this study, optimum forming methods and welding conditions were derived to develop double wall bellows made of austenite stainless steel. The reliability of the prototypes was ensured by various performance evaluations. In this study, the buckling load and bellows stress were obtained by structural design, buckling, and stress analysis to design optimum bellows. As a result, the buckling load in the embossing shape of bellows increased by approximately 1.6 times, and no buckling and squirming occurred at 30.0 bar, which was twice that of the maximum design pressure.

A Study on the Operating Management Method of Creative Engineering Design and Project Based Capstone Design for the Purpose of Improvement in the Quality of Engineering Education (공학교육 내실화를 위한 종합 설계 교과와 졸업 연구 작품 제작 활동의 운영 방안 연구)

  • Chang, Eun-Young
    • The Journal of Korean Institute for Practical Engineering Education
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    • v.2 no.2
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    • pp.23-29
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    • 2010
  • In this study, there is a modeling for the procedure and operational method of the project based capstone design and related products which are a certificate of graduate status, and those results were evaluated by self-review and the performance assessment. Finally, the improvements in the operating management method are proposed. Before one semester by the end of to the assessment, the design thesises of capstone results are fixed to the 15 sets by 2 people in each group. All teams are satisfied the criteria of evaluation, and they all got a grad over 60 points. The mean value of their's score are similar to the average of recent 5 years. The results of self-evaluations and questionaries indicate a totally self-satisfied(3.8~4points out of 5), but the weak parts of this procedure are known as the area of plan making and Implementation. Also, there are some problems associated with a group of people into a team by the human relation rather than knowledge based mutual supplementation.

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