• 한국정밀공학회지
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• 제17권9호
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• pp.95-101
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• 2000

This paper proposes a general structure observer and shows the characteristic of external noise reduction in linear discrete system. First we propose a simple genera structured observer which includes high gain term or PI(proportional integral) term to eatimate the states of system and show that the observer can estimate the states of system even if an external noise is added to the system's output. An existence condition of the observer is derived and checked by system's rank condition. Through a numerical example we can verify that the proposed observer is effective to estimate the state of system with external noise compared to that of conventional high gain observer.

• 대한기계학회논문집A
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• 제33권8호
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• pp.786-792
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• 2009

Topology optimization is to find the optimal material distribution of the specified design domain minimizing the objective function while satisfying the design constraints. Since the genetic algorithm (GA) has its advantage of locating global optimum with high probability, it has been applied to the topology optimization. To guarantee the structural connectivity, the concept of compliance pattern is proposed and to improve the convergence rate, small number of population size and variable probability in genetic operators are incorporated into GA. The rank sum weight method is applied to formulate the fitness function consisting of compliance, volume, connectivity and checkerboard pattern. To substantiate the proposed method design examples in the previous works are compared with respect to the number of function evaluation and objective function value. The comparative study shows that the compliance pattern based GA results in the reduction of computational cost to obtain the reasonable structural topology.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2004년도 추계학술대회 및 정기총회
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• pp.143-146
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• 2004

In a situation that rank order information on attribute weights is captured, two solution approaches are presented. An exact solution approach via interaction with a decision-maker pursues progressive reduction of a set of non-dominated alternatives by narrowing down the feasible attribute weights set. In approximate solution approach, on the other hand, three categories of approximate methods such as surrogate weights method, the dominance value-based decision rules, and three classical decision rules are presented and their efficacies in terms of choice accuracy are evaluated via simulation analysis. The simulation results indicate that a method, which combines an exact solution approach through interactions with the decision-maker and the dominance value-based approach is recommendable in a case that a decision is not made at a single step under imprecisely assessed weights information.

• KIEE International Transaction on Systems and Control
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• 제2D권2호
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• pp.115-119
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• 2002

In this paper we present a generalized directional morphological filtering algorithm for the removal of impulse noise, which is based on a combination of impulse noise detection and a weighted rank-order morphological filtering technique. For salt (or pepper) noise suppression, the generalized directional opening (or closing) filtering of the input signal is selectively used. The detection of impulse noise can be done by the geometrical difference of opening and closing filtering. Simulations show that this new filter has better detail feature preservation with effective noise reduction compared to other nonlinear filtering techniques.

• 대한인간공학회지
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• 제16권1호
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• pp.15-27
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• 1997

The objectives of this study were twofold; (1) to determine an optimal handle size of a signal billy, based on the subjective assessment of grip comfort and (2) to investigate the relationship between hand anthropometry and the optimal handle size. Thirty-seven university male students were asked to rate seven cylindrical handles of different diameters in barehanded and gloved conditions, respectively. Among these handles, 3.5cm diameter of the handle size was found to be the most comfortable, in both bardhanded and gloved conditionsl. However, no statistically significant reduction in grip comfort occurred within handle diameter ranging from 2.5cm to 4.0cm. As the handle diameter was deivated from the range, grip discomfort in creased significantly. A Spearman rank correlation coefficient test revealed that hand anthropometries such as finger lengths, hand circumference, and hand thickness were statistically significant factors on the determination of the optimal handle size. The implications of these findings were discussed. The results of this study can be used as guidelines in designing the hand tools for power grip.

• 한국음향학회:학술대회논문집
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• 한국음향학회 1994년도 FIFTH WESTERN PACIFIC REGIONAL ACOUSTICS CONFERENCE SEOUL KOREA
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• pp.836-841
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• 1994

This paper describes the global vibro-acoustic troubleshooting approach, used to identify and separate different sources of noise and vibrations on a boilerfeed pump testrig. The pump serves for rotor dynamic research of a EC-funded BRITE-Euram profect. This approach resulted in the identification of local structural flexibilities in the connections between the machinery and the base plate. The relative importance of the modes during normal operation is revealed by comparison with operational deformation shapes. The use of sound intensity mapping allowed to calculate the total sound power and to rank the equipment according to its sound power contribution. High acoustic levels were found and related to the fluid drive and to the piping system. Modification of the piping section resulted in a reduction of noise and vibration levels along the test loop and smooth operation in a wide suction pressure range.

• 한국작물학회지
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• 제46권5호
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• pp.380-386
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• 2001

Dry matter(DM) accumulation in different plant parts of two Vigna spp., blackgram(Vigna mungo) and mungbean(Vigna radiata), was compared at different levels of salinity. Two vaarieties of each of blackgram (Barimash-1 and Barimash-2) and mungbean(Barimung-3 and Barimung-4) were grown with 50, 75 and 100mM NaCl solutions and tap water as a control till maturity. The DM accumulation in all plant parts of the two crops devreased with the increasing salinity levels. The reducation was severe in mungbean compared to blackgram. On an average mungbean produced only 3% grain yield compared to 37% in blackgram at 100mM NaCl. The salinity induced growth reduction was relatively less in Barimash-2 than that in Barimash-1. In mungbean, the relative DM production of Barimung-3 was greater than Barimung-4. The extent of biomass reducation due to salinity in different plant parts was not similar. At maturity the rank of biomass accumulation (at 100 mM NaCl) in different plant parts of blackgram was in decreasing order by seeds pod$^{-1}$ (97%), branch plant$^{-1}$ (88%), 1000-grain weight (79%), plant height(72%), pods plant$^{-1}$ (50%), leaf weight and root mass(both 49%) and stem weight (48%). In mungbean, the rank was in decreasing order by 1000-grain weight (57%), leaf weight (54%), plant height (52%), seeds pod$^{-1}$ (50%), branch plant$^{-1}$ (41%), root weight (34%), stem weight (24%) and pods plant$^{-1}$ (6%). Therefore, salinity reduced grain yield more than straw and roots of the Vignaq spp., and blackgram is relatively more salt-tolerant than mungbean.

• 대한치과보철학회지
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• 제45권1호
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• pp.60-70
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• 2007

Statement of problem: The cement-type abutment would be needed for the reduction of its body in order to correct the axis and to assure occlusal clearance. In the case of intraoral preparation, there is a potential risk that generated heat could be transmitted into the bone-implant interface, where it can cause deterioration of tissues around the implant and failed osseointegration. Purpose: The purpose of this study was to assess the difference of the heat transmitting effect on external and internal connection implant types under various conditions. Material and method: For evaluating the effects of alternating temperature, the thermocoupling wires were attached on 3 areas of the implant fixture surface corresponding to the cervical, middle, and apex. The abutments were removed 1mm in depth horizontally with diamond burs and were polished for 30 seconds at low speed with silicone points using pressure as applied in routine clinical practice. Obtained data were analyzed using Mann-Whitney rank-sum test and Wilcoxon / Kruskal-Wallis Tests. Result: Increased temperature on bone-implant interface was evident without air-water spray coolant both at high speed reduction and low speed polishing (p<.05). But, the difference between connection types was not shown. Conclusion: The reduction procedure of abutment without using proper coolant leads to serious damage of oral tissues around the implant irrespective of external and internal connection type.

• The Journal of Advanced Prosthodontics
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• 제11권6호
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• pp.305-312
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• 2019

PURPOSE. The purpose of this study was to compare computer-aided design/computer-aided manufacturing (CAD/CAM) abutment and prefabricated abutment in Morse taper internal connection type implants after cyclic loading. MATERIALS AND METHODS. The study was conducted with internal type implants of two different manufacturers (Group Os, De). Fourteen assemblies were prepared for each manufacturer group and divided into 2 groups (n=7): prefabricated abutments (Os-P, De-P) and CAD/CAM abutments (Os-C, De-C). The amount of axial displacement and the removal torque values (RTVs) were measured before and after cyclic loading (10⁶ cycles, 3 Hz with 150 N), and the tensile removal force to dislodge the abutments was measured after cyclic loading. A repeated measures ANOVA and a pattern analysis based on the logarithmic regression model were conducted to evaluate the effect of cyclic loading on the axial displacement. The Wilcoxon signed-rank test and the Mann-Whitney test was conducted for comparison of RTV reduction% and tensile removal forces. RESULTS. There was no significant difference between CAD/CAM abutments and prefabricated abutments in axial displacement and tensile removal force; however, significantly greater RTV reduction% after cyclic loading was observed in CAD/CAM abutments. The correlation among the axial displacement, the RTV, and the tensile removal force was not significant. CONCLUSION. The use of CAD/CAM abutment did not significantly affect the amount of axial displacement and tensile removal force, but presented a significantly greater removal torque reduction% than prefabricated abutments. The connection stability due to the friction at the abutment-implant interface of CAD/CAM abutments may not be different from prefabricated abutment.

• Journal of Oral Medicine and Pain
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• 제41권1호
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• pp.1-6
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• 2016

Purpose: To investigate the efficacy of pregabalin for patients with primary burning mouth syndrome (BMS) who are unresponsive to topical clonazepam therapy. Methods: By searching the clinical electronic records from the Department of Oral Medicine, Pusan National University Dental Hospital from 2012 to 2014, a retrospective analysis was performed on patients with primary BMS who were treated with topical clonazepam therapy during this period. Of the patients who were unresponsive to this therapy, 19 patients who were subsequently treated with pregabalin were included in the study. A pain assessment was performed using the 11-point numerical rating scale at first visit, following topical clonazepam therapy, and again after pregabalin therapy. The treatment outcomes were statistically analyzed using the Wilcoxon signed rank test. Results: Following additional pregabalin administration, the mean pain score was slightly reduced. A total of 7 patients reported a marked response (>50% pain reduction), and 3 patients reported a slight reduction in pain. Pain reduction following pregabalin therapy was statistically significant (p<0.05). Conclusions: Pregabalin has a slight therapeutic effect on patients with primary BMS. Therefore, we recommend pregabalin as an alternative drug for BMS patients who are unresponsive to topical clonazepam therapy.