• Journal of the Ergonomics Society of Korea
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• v.31 no.6
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• pp.725-731
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• 2012

Objective: The aim of this study is to investigate visual feedback effects and human performance in the foot mouse control. Background: Generally, computer mouse tasks are controlled by visual feedback. In order to understand the characteristics of a foot mouse control, it is important to investigate the patterns of visual feedback involved in foot-mouse control tasks. Human performance of foot mouse control is also an important factor to understand the foot mouse control. Method: Three types of mouse control were determined to investigate visual feedback effects and human performance in the foot mouse control. Visual feedback effects in the foot mouse control were compared with those of a typical hand mouse. The cursor movement speed and mental workload were measured in the three types of tasks and two types of mouses. Results: Mouse control tasks with an element of homing-in to the target were more quickly performed by the hand mouse than the foot mouse. Mental workload was also higher in the foot mouse than the hand mouse. However, in the steering movement, human performance of the foot mouse control was not lower than that of the hand mouse control. Visual feedback in the foot mouse control was less required than in the hand mouse control. Conclusion: The foot mouse was not efficient in the most mouse control tasks, compared to the hand mouse. However, the foot mouse was efficient in the steering movement, moving a cursor within a path with lateral constraints. Application: The results of this study might help to develop the foot mouse.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.17 no.4
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• pp.520-530
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• 2010

Purpose: In this study influenza A (H1N1) infection control performance and stress in nurses were surveyed, to identify factors influencing stress for the nurses, and to provide basic materials for promoting infectious disease control by nurses. Method: The participants were 447 nurses who had worked at isolation clinics and/or isolation rooms in hub hospitals in the Honam region during the period of the outbreak of 2009 pandemic influenza A (H1N1) virus. Data were collected in February 2010 using self-report questionnaires. Results: The performance of participants from clinics was high for 'helping patients wearing masks', but low for 'maintaining distance over 1 meter among waiting patients'. The performance of participants from hospital rooms was high for 'putting a surgical mask on a patient going out of the room', but low for 'keeping patients' family out of the room'. The participants' stress was higher in those younger and less experienced nurses, those working at a hospital with 500-999 beds, those working at both isolation clinics and rooms, and those working at a clinic longer. Conclusion: In order to lower nurses' stress from working at isolation clinics/rooms for infectious diseases, we may need to deploy experienced nurses and limit their working days to five or less.

• Membrane Journal
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• v.23 no.5
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• pp.343-351
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• 2013

This study is to investigate the effects of the draw solution concentration on forward osmosis desalination performance using blended fertilizer as draw solution. As the concentration of blended fertilizer solution (draw solution) increased, the water permeate flux increased nearly linearly, but PR (performance ratio) was reduced. Using sea water and deionized water as the feed solution, respectively, at the blended fertilizer solution of 600 g/L $H_2O$, the PR obtained were 5.39 and 6.50, respectively. And as the concentration of blended fertilizer solution increased, the reverse solute flux for nitrogen (N), phosphorus (P), and potassium (K) increased nearly linearly, but specific reverse solute flux for them was reduced. The reverse solute flux and specific reverse solute flux became higher in the order of N > K > P.

• International Journal of Highway Engineering
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• v.15 no.2
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• pp.65-71
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• 2013

PURPOSES : The objective of this study is to evaluate the effect of physical characteristics of emulsion asphalt and aggregate on performance of chip seal pavements. METHODS : In order to evaluate the performance of chip seal materials, the sweep tests and Vialit Plate Shock tests were conducted on the mixtures with five emulsion asphalt binders and three aggregate types. The sweep tests was intended to investigate the change of bonding properties between emulsion asphalt and aggregate with curing time. The Vialit Plate Shock test was used to evaluate the bonding properties of chip seal materials at low temperatures. RESULTS : Results from sweep tests showed that polymer modified emulsion asphalt can reduce the curing time by 1.5 hour comparing with typical emulsion asphalt. It is also found that the Flakiness Index of aggregates and absorption rate of binder are the major factors affecting the bonding properties of chip seal materials. The Vialit Plate Shock test results showed that the average aggregate loss of CRS-2 is ten times higher than CRS-2P No.2 indicating that the use of polymer additives in emulsion asphalt can improve the performance of chip seal materials in low temperature region. CONCLUSIONS : The use of polymer in emulsion asphalt can decrease the curing time of chip seal materials and increase the bonding properties between aggregates and asphalt binder. It is also concluded that the lower Flakiness Index and absorption rate of aggregates can improve the performance of chip seal pavement.

• Korean Journal of Materials Research
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• v.30 no.1
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• pp.14-21
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• 2020

Carbon supports for dispersed platinum (Pt) electrocatalysts in direct methanol fuel cells (DMFCs) are being continuously developed to improve electrochemical performance and catalyst stability. However, carbon supports still require solutions to reduce costs and improve catalyst efficiency. In this study, we prepare well-dispersed Pt electrocatalysts by introducing titanium dioxide (TiO₂) into biomass based nitrogen-doped carbon supports. In order to obtain optimized electrochemical performance, different amounts of TiO₂ component are controlled by three types (Pt/TNC-2 wt%, Pt/TNC-4 wt%, and Pt/TNC-6 wt%). Especially, the anodic current density of Pt/TNC-4 wt% is 707.0 mA g^-1_pt, which is about 1.65 times higher than that of commercial Pt/C (429.1 mA g^-1_pt); Pt/TNC-4wt% also exhibits excellent catalytic stability, with a retention rate of 91 %. This novel support provides electrochemical performance improvement including several advantages of improved anodic current density and catalyst stability due to the well-dispersed Pt nanoparticles on the support by the introduction of TiO₂ component and nitrogen doping in carbon. Therefore, Pt/TNC-4 wt% may be electrocatalyst a promising catalyst as an anode for high-performance DMFCs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.3
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• pp.291-297
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• 2014

Due to the rapid increase in demand for transportation of human and freight in modern railway systems, the CBTC system has been proposed, which is the solution for improvement of the line capacity that has been limited by the conventional track circuit based train control system. In the CBTC system, higher reliability of the communication system should be guaranteed for the safety of passengers and trains. However, due to the inherent characteristics of the wireless channel environment, performance degradations are inevitable. The diversity techniques can increase the reliability of data transmission using multiple antennas. In this paper, we investigate the performance of the STBC in the railway channel environment. Rician fading model is used for the viaduct scenarios which take important roles in the railway system. Also, considered is the Doppler effect which is an important factor in the mobile communication system. Simulations are performed to analyze the performance of the STBC in various channel environments. Results show that the performance degradation due to the phase error in viaduct scenarios is independent of the diversity order but is affected by the constellation of the modulation.

• The Journal of the Convergence on Culture Technology
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• v.6 no.1
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• pp.179-183
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• 2020

Seligman argues that an optimistic athlete wins based on a study of US professional baseball and professional basketball players.(trans. Choi, 2008). So, the purpose of this study was to investigate whether optimism can predict the performance of badminton youth representatives. 60 high school students were divided into two groups according to their performance. We used the revised Life Orientation Test (LOT-R) developed by Scheier, Carver and Bridges(1994) and translated into Korean version by Shin Hyun-sook(2005). For this study, the data were analyzed by frequency analysis, reliability analysis, and independent t - test. As a result, there was a statistically significant higher level of optimism in the excellent group than in the non-excellent group. So, in order to improve sports performance, we need psychological skills training that can improve optimism as well as physical training and skills training.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.10
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• pp.885-892
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• 2013

The main advantage of ESPAR antenna is that ESPAR antenna requires only a single RF chain for reduction of transceiver's hardware complexity, as compared to conventional MIMO system. In conventional MIMO system, each data symbol is mapped to each antenna. But, each data symbol is mapped to each orthogonal basis pattern in ESPAR antenna system. In this paper, we design beamspace MIMO system using ESPAR antenna with single RF chain for MIMO system of low-complexity and low power consumption. And then, we analyze performance of beamspace MIMO according to each PSK modulation. Performance of beamspace MIMO system is similar to performance of conventional MIMO system. As a result of analyzing the performance of beamspace MIMO system using higher-order PSK modulation. we can confirm that performance characteristic of beamspace MIMO system with low complexity and low power consumption is similar to digital communication of signal domain.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.8-14
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• 2019

In Korean traditional wooden architecture, joint performance varies with the material characteristics of timber, the form of joint, the precision of timber-trimming and the like. Case studies prove that the beam-to-column joint type has large influence on the degrees of deformation and spacing. This is not only true of single-story buildings, but also of large-scale multi-story buildings more apparently. Therefore, this study followed the process of examining to joint types, producing their specimens and testing their structural performance. As a consequence of structural test, the dovetail joint specimen showed the best outcomes of the maximum load and rigidity. Synthesizing the structural performances by respective forms of joints, the Doraegeoji dovetail joint specimen showed the higher performance, followed in order by the Doraegeoji mortise joint specimen and the Tongneoko dovetail joint specimen. The structural performance of a building varies with the characteristics by the shouldering forms of penetrating beams and with the joint types within the columns. This should be considered for the new construction or restoration of multi-story buildings, and be continuously researched henceforth.

• Journal of Korean Society for Quality Management
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• v.47 no.1
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• pp.17-32
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• 2019

Purpose: CMMI is a process model used to assess or improve an organization's software development capabilities. This paper deals with the quality indicators when using CMMI and their priorities for possible improvement. Methods: The 22 process areas and 167 practices of CMMI are matched with 60 indicators of Quality Scorecard(QSC) first to analyze the balance of CMMI in terms of prevention, appraisal, and final result categories and second to isolate a set of key areas for quality focused performance measures. Results: A total of 86.2% (144 out of 167) CMMI practices were mapped to QSC. According to the CMMI level of maturity, level 2 and 3 accounted for more than 75% of the total. The practices at the maturity level of 4 and 5 were mapped to more than 52% of the final result's measurements. It has been observed that CMMI practices need further elaboration at higher levels to consider prevention, appraisal, and final results simultaneously. Conclusion: In order to improve the quality performance of the organization by applying CMMI, the final result measures should be refined in metrics, cycles, and methods, and then corrective actions could be conducted to improve the performance of CMMI practices. This strategy would help the practitioners benefit from CMMI in fostering the overall quality level of key activities for the organization's business goals.