• Title/Summary/Keyword: grader consistency

Search Result 4, Processing Time 0.018 seconds

Development of Weight Sensing Unit of Fruit Weight Grader Using Load Cell (중량선과기(重量選果機)의 중량감지부(重量感知部) 개선(改善)에 관(關)한 연구(硏究))

  • Kim, H.S.;Koh, H.K.
    • Journal of Biosystems Engineering
    • /
    • v.18 no.4
    • /
    • pp.358-370
    • /
    • 1993
  • In Korea, fruit grading has been mainly done manually, and manual grading depends on human sense. Thus it is subjected to human error and is not always as consistent as would be desired. Therefore, a study on the development of fruit grader was initiated to improve the consistency of fruit grading. The sensitivity for fruit weight of the conventional spring type weight grader has a tendency to decrease by physical characteristics of spring which is used as a weight sensing unit. This study was carried out to develop weight measuring device for establishing the base of weight sensing unit of electronic weight grader. This device consists of a weight sensor using load cell, data acquisition system, and a microcomputer containing program to calculate fruit weight. The weight measuring device using load cell was developed to increase sensitivity of fruit weight. The result of this study showed that the weight sensing unit of electronic weight grader contributed to the improvement of performance of weight measuring device.

  • PDF

The Development of an Instrument for the Measuring Cognitive Conflict Levels of Elementary Students Confronted with an Anomalous Situation in Science Learning (과학학습에서 불일치 상황에 대면한 초등학생의 인지갈등 측정 도구 개발)

  • 박상석;이경호;김정환;권혁구;권재술
    • Journal of Korean Elementary Science Education
    • /
    • v.18 no.2
    • /
    • pp.21-33
    • /
    • 1999
  • The purpose of this study was to develop an Instrument for the Measurement of Cognitive Conflict Levels of students who confronted with an anomalous situation in science teaming. Anomalous situation is generated when students' prediction is disconsistent with the observed fact. In this study, the researchers identified 4 components of cognitive conflict and developed three items for each component. The items were developed and revised by four pilot tests. In the first pilot test, 55 elementary school students participated in the test In the second pilot test, 88 students of the 5th and 6th grader participated in the test. The instrument of measuring cognitive conflict levels was given to the subjects right after demonstrating anomalous situation. For the demonstration, two different problem situations were developed: one was a pulley problem and the other was electric bulbs in parallel. Answered reasons for each items were analyzed to assess students' understanding on each items. In third pilot test, 125 elementary school students participated in the test. A factor analysis of the responses was carried out and reliability of the test was assessed by calculating internal consistency values. The items were finalized by three pilot tests. After 1 month after the third pilot test, researchers conducted the finalized test items to 323 students of the 5th and 6th grader. The final instrument showed moderate reliability (Cronbach-α 0.82∼0.87) and good content validity(0.93). A factor analysis of the response was carried out. 4 main factors completely coincided with 4 components that we supposed to be the conducts of cognitive conflict. The instrument can provide a means for both teachers and researchers to assess the cognitive conflict of a large number of students within a single class period. The results can be used by teachers to better understand the process of conceptual change of their students and to match instruction and materials accordingly.

  • PDF

A Study on Development of Problems for Descriptive Evaluation in Grade 7 Mathematics (중학교 1학년 수학과 서술형 평가문항 개발 연구)

  • Noh, Sun-Sook;Kim, Min-Kyeong;Cho, Seong-Min;Baek, Hae-Jin
    • The Mathematical Education
    • /
    • v.47 no.4
    • /
    • pp.487-503
    • /
    • 2008
  • In this paper, descriptive assessment method for middle school mathematics was evaluated by developing a framework for designing and grading problems for descriptive assessment and analyzing the effectiveness of the problems. The new descriptive assessment problems were developed by reviewing the current 7th National Mathematics Curriculum of Korea and aligned mathematics textbooks to define a set of problem design principles and evaluation framework for the assessment strategy. The developed problems were first pilot tested and then revised based on the feedback from the test. The final version was field tested by 100 students in 7th grade middle school. After the field test, the problems were graded by two middle school math teachers and one math education researcher to determine the overall correlation between graders and also to analyze effectiveness of the evaluation framework of the test. This result of this study is expected to assist in the further development of descriptive problems and grading framework by providing a reference work for teachers to better understand the process and the limitations of executing the new assessment strategy.

  • PDF

Trend and Further Research of Rice Quality Evaluation (쌀의 품질평가 현황과 금후 연구방향)

  • Son, Jong-Rok;Kim, Jae-Hyun;Lee, Jung-Il;Youn, Young-Hwan;Kim, Jae-Kyu;Hwang, Hung-Goo;Moon, Hun-Pal
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.47
    • /
    • pp.33-54
    • /
    • 2002
  • Rice quality is much dependent on the pre-and post harvest management. There are many parameters which influence rice or cooked rice qualitys such as cultivars, climate, soil, harvest time, drying, milling, storage, safety, nutritive value, taste, marketing, eating, cooking conditions, and each nations' food culture. Thus, vice evaluation might not be carried out by only some parameters. Physicochemical evaluation of rice deals with amy-lose content, gelatinizing property, and its relation with taste. The amylose content of good vice in Korea is defined at 17 to 20%. Other parameters considered are as follows; ratio of protein body-1 per total protein amount in relation to taste, and oleic/linoleic acid ratio in relation to storage safety. The rice higher Mg/K ratio is considered as high quality. The optimum value is over 1.5 to 1.6. It was reported that the contents of oligosaccharide, glutamic acid or its derivatives and its proportionalities have high corelation with the taste of rice. Major aromatic compounds in rice have been known as hexanal, acetone, pentanal, butanal, octanal, and heptanal. Recently, it was found that muco-polysaccharides are solubilized during cooking. Cooked rice surface is coated by the muco-polysaccharide. The muco-polysaccharide aye contributing to the consistency and collecting free amino acids and vitamins. Thus, these parameters might be regarded as important items for quality and taste evaluation of rice. Ingredients of rice related with the taste are not confined to the total rice grain. In the internal kernel, starch is main component but nitrogen and mineral compounds are localized at the external kernel. The ingredients related with taste are contained in 91 to 86% part of the outside kernel. For safety that is considered an important evaluation item of rice quality, each residual tolerance limit for agricultural chemicals must be adopted in our country. During drying, rice quality can decline by the reasons of high drying temperature, overdrying, and rapid drying. These result in cracked grain or decolored kernel. Intrinsic enzymes react partially during the rice storage. Because of these enzymes, starch, lipid, or protein can be slowly degraded, resulting in the decline of appearance quality, occurrence of aging aroma, and increased hardness of cooked rice. Milling conditions concerned with quality are paddy quality, milling method, and milling machines. To produce high quality rice, head rice must contain over three fourths of the normal rice kernels, and broken, damaged, colored, and immature kernels must be eliminated. In addition to milling equipment, color sorter and length grader must be installed for the production of such rice. Head rice was examined using the 45 brand rices circulating in Korea, Japan, America, Australia, and China. It was found that the head rice rate of brand rice in our country was approximately 57.4% and 80-86% in foreign countries. In order to develop a rice quality evaluation system, evaluation of technics must be further developed : more detailed measure of qualities, search for taste-related components, creation and grade classification of quality evaluation factors at each management stage of treatment after harvest, evaluation of rice as food material as well as for rice cooking, and method development for simple evaluation and establishment of equation for palatability. On policy concerns, the following must be conducted : development of price discrimination in conformity to rice cultivar and grade under the basis of quality evaluation method, fixation of head rice branding, and introduction of low temperature circulation.