• Transactions of Materials Processing
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• v.9 no.4
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• pp.413-420
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• 2000

In the die casting process, the flow of liquid metal has significant influence on the quality of casting products and die life. For the optimal process design of front housing part of aircon compressor, various analyses were performed in this study by using computer simulation code, MAGMAsoft. The simulation has been focused on the molten metal behaviors during the filling and solidification stages for the sound casting products. Two cases of casting design that have different types of gating system are considered in the analysis. The potential sites where the casting defects may occur is examined by computer simulation and an improved design process is proposed. Also the effect of partial squeeze on the quality of casting products is considered and the optimal time lag after filling process is determined. For the die-stability, the effect of operational parameters such as die temperature, heat cycle and spot cooling on the die life has also been analyzed.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.772-774
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• 1997

Small-signal stability analysis of large power systems needs the calculation of eigenvalues. But we use the partial eigenanalysis to calculate rightmost eigenvalues, since system matrix is very large. This paper proposes the Arnoldi-Chebyshev method identifying rightmost eigenvalues. This method constructs an optimal ellipse containing unwanted eigenvalues and use the Chebyshev iteration to get approximate eigenvetors corresponding to wanted eigenvalues, and then applies the modified Arnoldi method to calculate wanted eigenvalues.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.1
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• pp.67-74
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• 2017

PURPOSE: The purpose of this study was to determine the effect of action observation with observation type on the limits of stability and dynamic gait ability in stroke patients. METHODS: The 20 stroke patients who participated in this study were randomly divided into two experimental groups who underwent training three times a week for 4 weeks. Their balance was tested as the limit of stability with Biorescue. Their Dynamic gait ability was tested with the Dynamic Gait Index (DGI) before the intervention, and after 4 weeks. Independent and paired t-tests were used to analyze the results. RESULTS: The results confirmed the limit of stability on the moving areas of the paralyzed and non-paralyzed sides. The limit of stability and dynamic gait index measurements confirmed that the moving area showed a significant difference after the intervention in the whole movement observation group (p<.05), but the partial movement observation group showed no significant difference (p>.05). A significant difference was also noted for the comparison between the both groups after the interventions (p<.05). The functional walking ability showed a significant difference when compared to the ability before the intervention, as determined by the changes in scores obtained for the dynamic gait index (p<.05). CONCLUSION: Interventions utilizing whole movement confirm that training improves stability and functional walking ability in stroke patients with disabilities in balance and walking ability.

• Korean Journal of Food Science and Technology
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• v.46 no.5
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• pp.593-600
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• 2014

Normal rice starch (NRS) possesses high gelling and retrogradation tendencies, with poor freeze-thaw stability. This study investigated the effects of partial replacement of waxy rice starch (WRS) with gums on the pasting and viscoelastic properties as well as the freeze-thaw stability of the WRS paste. Xanthan gum (XAT), locust bean gum (LBG), and their mixtures were individually mixed with WRS at a ratio of 1:19 (w/w). WRS-gum mixtures were pasted using a rapid visco-analyzer at 5% total solid content, and analyzed with respect to the pasting and viscoelastic characteristics, and freeze-thaw stability. Pasting properties of WRS were retarded in pasting temperature and enhanced in pasting viscosity (although peak viscosity was varied) by partial replacement with gum and gum mixtures. Storage moduli of WRS-XAT:LBG pastes became similar to those of NRS paste with increasing angular frequency from 1 to 10 rad/s. Finally, WRS-XAT and WRS-XAT:LBG possessed more enhanced freeze-thaw stability than NRS.

• Journal of Korean Orthopaedic Sports Medicine
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• v.1 no.2
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• pp.131-137
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• 2002

Purpose: To evaluate and compare the functional results, activity status, and anterior stability between conservative group with partial ACL injury and reconstruction group with bone-patellar ten-don-bone autograft in ACL total rupture. Materials and Methods: Thirty-eight patients with ACL injury were diagnosed and treated with arthroscopy and followed for more than two years. The number of patients with partial injury was 12(mean age; 38.3) and reconstruction group was 26 (mean age; 25.3). Objective stability was estimated under anterior loading of 15 lb and 20 lb by KT-2000 Arthrometer (MED metric, USA). Functional evaluation using Lysholm score and Tegner activity score were performed. Results: Average functional score of Lysholm was 88.5 in partial injury group and 89.3 in reconstruction group. Average score of Tegner was 5.3 in partial injury group and 5.1 in reconstruction group(P<0.05).Average anterior displacement compared with normal side. Under loading of 20lb, 1.7$\pm$4.3 mm in partial injury group, 2.3$\pm$1.9 mm in reconstruction group were anterior displaced (P<0.05). Under loading of 15lb, 1.2$\pm$1.0 mm in partial injury group, 1.4$\pm$1.5 mm in reconstruction group were dis-placed (P<0.05). There were giving way, effusion, instability and anterior knee pain in complication. Giving way was the frequent complication in the partial injury group. Conclusions: Clinical results of both group were similar. Functional evaluation of Lysholm was good and status of Tegner activity was maintained to physical fitness activites (jogging, regular bik-ing) in both groups on average. The results of conservative treatment for the partial ACL injury (less than 50$\%$) was satisfactory and equivalent to that of reconstructive treatment for the total ACL injury.

• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.426-440
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• 2020

This study was conducted to confirm the mediating effect of the teacher's trust in the relationship between the classroom teacher's transformative leadership and the students' emotional stability from the organizational perspective. For this, the data from 290 middle school students in Seoul were collected and analyzed. As a result of the study, the transformative leadership of the homeroom teacher had a positive (+) effect on the trust of the leader. In addition, the teacher's trust in the leader had a positive (+) effect on the learner's emotional stability. In addition, it was confirmed that the teacher's transformational leadership had a positive (+) effect on the learner's emotional stability. Finally, in the relationship between the homeroom teacher's transformative leadership and the learner's emotional stability, teacher trust has a partial mediating effect. This study is meaningful in that it has objectively verified what kind of leadership the homeroom teacher should aim for in order to operate the classroom as the peripheral unit of the school organization, and what emotional and psychological effects such leadership can have on students who are members of the organization.

• Industry Promotion Research
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• v.8 no.2
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• pp.93-100
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• 2023

This study used Gangwon provincial social survey data(2021) to verify the effect of working environment satisfaction of the main working population on settlement consciousness and the mediating effect of subject employment stability. The working environment satisfaction was analyzed by dividing it into three sub-factors: income satisfaction, working conditions satisfaction, and community life satisfaction. As a result of the study, all three sub-factors of working environment satisfaction and subjective employment stability had a positive correlations with settlement consciousness. It was confirmed that subjective employment stability had a partial mediating effect when each of the three sub-factors of working environment satisfaction affected settlement consciousness. Based on the results of the study, it is meaningful to provide empirical data for preventing outflow of the local population by revealing the effect of working environment satisfaction and subjective employment stability on the settlement consciousness.

• Structural Engineering and Mechanics
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• v.11 no.3
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• pp.287-299
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• 2001

Columns in multi-storey frames are presently categorised as either braced or unbraced, usually by means of the stability index criterion, for estimating their effective length ratios by design aids such as 'alignment charts'. This procedure, however, ignores the transition in buckling behaviour between the braced condition and the unbraced one. Hence, this results in either an overestimation or an underestimation of effective length estimates of columns in frames that are in fact 'partially braced'. It is shown in this paper that the transitional behaviour is gradual, and can be approximately modelled by means of a 'fuzzy logic' based technique. The proposed technique is simple and intuitively agreeable. It fills the existing gap between the braced and unbraced conditions in present codal provisions.

• International Journal of Control, Automation, and Systems
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• v.2 no.1
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• pp.55-67
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• 2004

In this paper, an active vibration control of a translating steel strip in a zinc galvanizing line is investigated. The control objectives in the galvanizing line are to improve the uniformity of the zinc deposit on the strip surfaces and to reduce the zinc consumption. The translating steel strip is modeled as a moving belt equation by using Hamilton’s principle for systems with moving mass. The total mechanical energy of the strip is considered to be a Lyapunov function candidate. A nonlinear boundary control law that assures the exponential stability of the closed loop system is derived. The existence of a closed-loop solution is shown by proving that the closed-loop dynamics is dissipative. Simulation results are provided.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.342-347
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• 2003

In this paper, an active vibration control of a translating tensioned string with the use of an electro-hydraulic servo mechanism at the right boundary is investigated. The dynamics of the moving strip is modeled as a string with tension by using Hamilton’s principle for the systems with changing mass. The control objective is to suppress the transverse vibrations of the strip via boundary control. A right boundary control law in the form of current input to the servo valve based upon the Lyapunov’s second method is derived. It is revealed that a time-varying boundary force and a suitable passive damping at the right boundary can successfully suppress the transverse vibrations. The exponential stability of the closed loop system is proved. The effectiveness of the control laws proposed is demonstrated via simulations.