• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.3
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• pp.209-215
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• 2005

Since a transcritical $CO_2$ cycle shows lower performance than conventional air conditioners in the cooling mode operation, it is required to enhance the performance of the $CO_2$ cycle by applying advanced technologies and optimizing components. In this study, the cooling performance of a $CO_2$ system measured by varying refrigerant charge amount, compressor frequency, EEV opening and length of internal heat exchanger. As a result, the cooling COP of the basic system without internal heat exchanger was 2.1. The cooling performance of the modified cycle applying internal heat exchanger improved by $4-9\%$ over the basic cycle.

• Research in Mathematical Education
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• v.16 no.3
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• pp.155-176
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• 2012

It is an important issue to explore classroom environments which are conducive to developing students' mathematical performance. This study explores the effects of different classroom environments (solution-demand and corresponding-time setting) on mathematical performances. Fourteen and eighteen prospective teachers were required to prove a task under different conditions respectively: a) Cognitive demand of multiple-solution corresponding time of three hours, and b) Cognitive demand of a right solution corresponding time of 20 minutes. We used SOLO as the assessment tool for mathematical performance from quality perspective. Significant differences were found in the quantity and quality of mathematical performance. The regular environment focusing on speed and accuracy were found to be directly linked to low levels of performance. The findings above provide implications to the cognitive benefits of multiple-solution demand and corresponding time setting.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2548-2553
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• 2008

Prediction of the rotor blade performance is important for determining design factors such as weight and size in development of a small-scale helicopter. Generally, prediction of helicopter performance means the estimation of the power required for a given flight condition. However, due to lack of test data and analyzed results for small-scale rotor blade operated at low Reynolds numbers ($Re{\approx}10^5$), this is not an easy task. As an initial research, this work performs a modeling of a single rotor configuration with FLIGHTLAB and a experimental research with rotor test bed. In this process, we performed small-scale isolated single rotor by experimental and numerical method and achieved good agreement of the hover performance on the test data and simulation results.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.595-602
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• 2023

Feed processing methods can substantially enhance the nutrient value of feed. The aim of our study was to compare the effects of mash or crumble feed on growth performance, nutrient digestibility, back-fat thickness, and carcass quality of growing-finishing pigs. In total, 50 ([Landrace × Yorkshire] × Duroc) growing pigs with initial body weight of 46.24 ± 3.57 kg were randomly assigned to two dietary treatment groups. The two dietary treatments were: 1) mash and 2) crumble feed forms for 14 weeks of trials. Five replication pens per treatment, comprised five pigs (2 males and 3 females) each. Growth performance, nutrient digestibility, back-fat thickness, and carcass quality were observed at different weeks. There were no significant differences in growth performance, nutrient digestibility, back-fat thickness, and carcass quality throughout the experimental trial. Further study is required to understand the effects of mash and crumble feed on growing-finishing pigs.

• ETRI Journal
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• v.25 no.1
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• pp.1-8
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• 2003

This paper introduces an efficient iterative decoding method for high-dimensional block turbo codes. To improve the decoding performance, we modified the soft decision Viterbi decoding algorithm, which is a trellis-based method. The iteration number can be significantly reduced in the soft output decoding process by applying multiple usage of extrinsic reliability information from all available axes and appropriately normalizing them. Our simulation results reveal that the proposed decoding process needs only about 30% of the iterations required to obtain the same performance with the conventional method at a bit error rate range of $10^{-5}\;to\;10^{-6}$.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.67-68
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• 2016

The accurate measurement of magnet power supplies (MPS) output currents is essential to delivering stable and repeatable currents to magnets in particle accelerators. An essential element in guaranteeing and evaluating the required performance is the current measurement device and methode. In this paper, we discuss instrument and methods for precision current measurement and performance of the PLS-II MPS.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.1
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• pp.34-40
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• 1994

The design and implementation of a fuzzy self-organizing controller for an environmental temperature chamber is discussed. The chamber is a non-linear, time-variant system with delay-time and dead-time. And the parameter tuning is required in PI control when the performance degraded. However the proposed fuzzy-SOC monitors the performance of the process. modifies the data base, and performs the delay-time compensation based on the idealized process model. A series of experiments was performed for the conventional PI and the fuzzy-SOC. These experimental results show the usefulness of the fuzzy-SOC.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.227-231
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• 1995

This paper describes a basic programming and interfacing modele which can link DataBase form experiments and dynamic analysis program of chock absorber within the limit of adequate reliability. The system developed can provid a user specific Database of shock absorber within the required damping performance and endurable tolerance, thus show a good application possibilities in commercial vehicle design.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.17 no.1
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• pp.23-30
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• 2014

Manometry is a noninvasive diagnostic tool for identifying motility dysfunction of the gastrointestinal tract. Despite the great technical advances in monitoring motility, performance of the study in pediatric patients has several limitations that should be considered during the procedure and interpretation of the test results. This article reviews the clinical applications of conventional esophageal and anorectal manometries in children by describing a technique for performing the test. This review will develop the uniformity required for the methods of performance, the parameters for measurement, and interpretation of test results that could be applied in pediatric clinical practice.

• IE interfaces
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• v.11 no.3
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• pp.227-240
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• 1998

This article presents a model for Intelligent Groupware Systems(IGS). The model is concerned not just with a future framework, but attempts to integrate many technologies into the framework. In order to do so, first of all it identifies essential technologies to improve the performance of the components in the model in terms of task-independent technologies(TIT) and task-dependent technologies(TDT). The former mainly consists of current technologies, which is under progress, being able to affect the groupware performance greatly. On the other hand, the latter is closely related to the knowledge depending on application systems. Fianlly, it presents these potential technologies which will be required for the IGS.