• Title/Summary/Keyword: Back-testing

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Coding of students′ thinking process in Polya′s stages of problem solving (Polya의 문제해결 각 단계에서 학생들이 보인 사고과정의 코드화)

  • 김소균;신현성
    • Journal of the Korean School Mathematics Society
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    • v.5 no.2
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    • pp.23-31
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    • 2002
  • The purpose of this study is to analyze thinking process in problem solving and to get some teaching materials to improve students' problem solving abilities. For this study, 14 girl and boy students in highschool were tested with 7 testing questions. The whole process of students' problem solving was observed by using 'Thinking aloud', recorded by Audio Tape and finally drawn up to Protocol. On the basis of that Protocol, coding system was set up and characteristics of thinking process in each stage were analyzed. -In the stage of planning, successful problem solvers tried to check the properties of words included in problems(Pr) and made it clear that they were seeking(O) -In the stage of planning, students used abstraction strategy(Ab, making equation(E) or using variable(V)) appropriately could solve more difficult problems. Successful problem solvers turned used unsystematical trial into systematical method and were good at using partial objects, assistant factors. - In the stage of carring out the plan, successful problem solvers to reduce the error, check the purpose, used formula, knowledge and calculation. -In the looking back stage, successful problem solvers generalized the answer and checked the total process.

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Materials and Electrochemistry: Present and Future Battery

  • Paul, Subir
    • Journal of Electrochemical Science and Technology
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    • v.7 no.2
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    • pp.115-131
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    • 2016
  • Though battery chemistry and technology had been developed for over a hundred years back, increase in demand for storage energy, in the computer accessories, cell phones, automobile industries for future battery car and uninterrupted power supply, has made, the development of existing and new battery, as an emerging areas of research. With innovation of high energetic inexpensive Nano structure materials, a more energy efficient battery with lower cost can be competitive with the present primary and rechargeable batteries. Materials electrochemistry of electrode materials, their synthesis and testing have been explained in the present paper to find new high efficient battery materials. The paper discusses fundamental of electrochemistry in finding true cell potential, overvoltages, current, specific energy of various combinations of anode-cathode system. It also describes of finding the performance of new electrode materials by various experiments viz. i. Cyclic Voltammetry ii. Chronoamperometry iii. Potentiodynamic Polarization iv. Electrochemical Impedance Spectroscopy (EIS). Research works of different battery materials scientists are discussed for the development of existing battery materials and new nano materials for high energetic electrodes. Problems and prospects of a few promising future batteries are explained.

The Determination of Control Limit and Testing Interval in the On-Line Quality Control of Taguchi Method (Taguchi Method의 On-Line Quality control에 있어서 관리한계 및 검사간격 결정에 대한 연구)

  • Kim, Uk-Il;Gang, Chang-Uk
    • Journal of Korean Society for Quality Management
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    • v.20 no.2
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    • pp.11-20
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    • 1992
  • We discuss the feed back control of the on-line QC in the Taguchi method. Taguchi(1982) used the assumptions that the quality characteristics follow an uniform distribution and the Brownian motion to draw the loss function and proposed ${\Delta}/3$ or ${\Delta}$ for the initial control limit. Adams and Woodall(1989) also proposed a different procedure but using the same loss function. We propose, in this paper the new loss function under the assumption of mainly Brownian motion and compare the results with the results of the above.

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Distributed Temperature Measurement Based on Raman Backscattering Light (Raman 역산란광을 이용한 온도분포 계측특성)

  • Kim, Y.H.;Oh, S.K.;Park, H.S.;Lee, H.C.;Roh, J.D.
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2447-2449
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    • 1999
  • This paper presents a distributed temperature sensor which uses a multimode optical fiber. The temperature distribution is derived from the intensity of the Raman back scattering light. Testing the sensors on measurement length of 2km of this system shows good temperature characteristics of the heated/cooled section. These performance will useful to design such as monitoring abnormal temperature rise of electric facilities.

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Multidisciplinary optimization of collapsible cylindrical energy absorbers under axial impact load

  • Mirzaei, M.;Akbarshahi, H.;Shakeri, M.;Sadighi, M.
    • Structural Engineering and Mechanics
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    • v.44 no.3
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    • pp.325-337
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    • 2012
  • In this article, the multi-objective optimization of cylindrical aluminum tubes under axial impact load is presented. The specific absorbed energy and the maximum crushing force are considered as objective functions. The geometric dimensions of tubes including diameter, length and thickness are chosen as design variables. D/t and L/D ratios are constricted in the range of which collapsing of tubes occurs in concertina or diamond mode. The Non-dominated Sorting Genetic Algorithm-II is applied to obtain the Pareto optimal solutions. A back-propagation neural network is constructed as the surrogate model to formulate the mapping between the design variables and the objective functions. The finite element software ABAQUS/Explicit is used to generate the training and test sets for the artificial neural networks. To validate the results of finite element model, several impact tests are carried out using drop hammer testing machine.

A Study on the Vibration and Dropping Shock of Refrigerator during Physical Distribution (냉장고의 유통 중 진동 및 낙하충격에 관한 연구)

  • Lee, Soo-Keun
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.8 no.1
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    • pp.23-26
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    • 2002
  • This study was carried out to investigate vibration shock and dropping shock of refrigerator during physical distribution. The values of vibration shock were measured to be ${\sim}3G$ for up and down direction, ${\sim}0.8G$ for right and left direction and ${\sim}0.5G$ for back and forth direction on the national road. There was no damage during transport. From the results of dropping test by KS A 1026(General Rules of Performance Testing for Packaged Freights), relative equations were gained as follow : y = 0.12x + 7.63(where y is G-factor and x is Dropping height). The maximum values of dropping shock during materials handling were measured to be 11G. This shock value was corresponding to dropping shocks of dropping height 28.3cm by KS A 1026.

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What went wrong?: The case of the non-selected alternate members of the Central Committee from 1992 to 2007

  • Payette, Alex
    • Journal of Contemporary Eastern Asia
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    • v.15 no.2
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    • pp.111-144
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    • 2016
  • Alternate members of the Chinese Communist Central Committee are often overlooked regarding elite formation or even when assessing Chinese elites in general. This article focuses on the case of alternate members of the Central Committee from 1992 to 2007 in order to understand why some individuals will eventually be promoted and why some will never be. Through extensive quantitative testing, I argue that these non-promoted individuals differ from their counterparts in many ways, most of which can possibly be traced back to the type of formation they received early on. As such, the article concludes that Party School attendance and the age factor, through threshold analysis, are a significant factor helping us understand the difference between promoted and non-promoted houbu.

Fabrication of Superconducting Dual Mode Resonator using Laser Ablation (레이저 어블레이션에 의한 초전도 이중모드 공진기 제작)

  • Park, Joo-Hyung;Yang, Seung-Ho;Lee, Sang-Yeol;Ahn, Dal;Sok, Jung-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.06a
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    • pp.41-44
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    • 1998
  • Dual mode resonators were fabricated using high temperature superconductor. The deposited material was $Y_1Ba_2Cu_3O_{7-x}$(YBCO) on MgO(100) substrate using pulsed laser deposition. Dual mode resonators were patterned by standard photolithography process and wet etching. At the back-side of the substrate, the ground plane with the metal layer of Ti and Ag was fabricated. The transition temperatures of YBCO films were 85-88 K, and network analyzer was used for testing the performance of the resonators. The input/output feedline angles of each resonator were $60^{\circ}$and $100^{\circ}$. The resonant frequency of resonators was 10 GHz. In this paper, dual mode resonator was fabricated for the application of satellite communication.

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A Study on the Adhesion Performance of Solid Forming Angle at Fiber Panel in the Water Supply Facility (수처리 시설물에 적용되는 섬유패널 배면부의 입체 성형 각도에 따른 부착 성능 연구)

  • Youn, Joon-No;Park, Wan-Goo;Choi, Su-Young;Kim, Dong-Bum;Kim, Byoung-Il;Oh, Sang-Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2018.11a
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    • pp.171-172
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    • 2018
  • The purpose of this study is to confirm the adhesion performance of the three - dimensional forming fiber panels by the dimensional forming angle. As a result of applying the three dimensional surface shape to the back side of the fiber panel and testing the adhesion strength by the three dimensional forming angle, it was confirmed that the bonding strength of the specimens to which the dimensional molding was applied was higher than that of the non dimensional molding. In addition, the highest adhesion strength was confirmed in a specimen having a three-dimensional forming angle of 70 °.

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The Effects of Service Quality of Ship Management Company on Customer Satisfaction and Customer Loyalty (선박관리회사의 서비스품질이 고객만족 및 고객충성도에 미치는 영향)

  • KWAK, Choong-Gon;PARK, Jong-Un;BACK, In-Heum
    • Journal of Fisheries and Marine Sciences Education
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    • v.28 no.5
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    • pp.1378-1387
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    • 2016
  • The purpose of this study is to extract the factors affecting service quality, customer satisfaction, and customer loyalty and to find out what effect service quality & customer satisfaction, service quality & customer loyalty, and customer satisfaction & customer loyalty respectively. The results of hypothesis testing through regression analysis showed that the hypothesis between service quality of ship management company and customer satisfaction was accepted in terms of all 5 service quality dimensions of tangibility, reliability, responsiveness, assurance and empathy. Also, the hypothesis between service quality of ship management companies and customer loyalty was accepted in terms of all 5 service quality dimensions of tangibility, reliability, responsiveness, assurance and empathy. Lastly, the hypothesis between customer satisfaction and customer loyalty was accepted.