• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.3
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• pp.210-215
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• 2016

The transient characteristics of the Mg/Air fuel cell were ascribed to the load current, electrolyte concentrations, air electrode area and electrode distance. It was found that transient phenomena occurred in the load current, which is due to activate of the oxidation and reduction reaction process. The transient time increase with the load current increase. The transient characteristics were investigated with regard to internal resistance. The maximum power output analysis was employed in order to explain the delayed action under various experimental conditions. The internal resistances had a significant effect on the transient characteristics. The transient curves thus obtained were in almost agreement with internal resistance characteristics.

• Journal of Korean Academy of Nursing
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• v.29 no.1
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• pp.61-71
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• 1999

Sleep is a necessity for survival. Disruption of sleep leads to numerous adverse physiological and psychological consequences. These could be particularly undesirable for older patients, who are subject to many additional factors. But there is limited research related to hospitalized elderly in Korea. The purpose of the study is to explore sleep patterns and disturbing factors of before and after hospitalization, in order to present basic information regarding elderly sleep to develop nursing intervention. The sample consisted of 32 elderly men and women between the ages of n and 87 years. Data collection was done from September to November 1997. Measures of sleep patterns and related factors were obtained from self-reported sleep questionnaires. Analysis of data was done by use of t-test, paired t-test, ANOVA, and Pearson Correlation Coefficient. The results of this study were summarized as follows : 1. In comparision between before and after admission of their sleep pattern, “sleep onset” tends to be delayed and nocturnal sleep time was significantly reduced. So, hospitalized elderly reported less total sleep time than before admission. 2. Regarding the sleep disturbing factors, medication(hypnotics ; 37.5%), physiological factor (snoring ; 59.4%) environmental factor (pillow ; 78.1%), emotional factor(anxiety related to disease ; 37.5%), and illness factor(fatigue ; 34.7%) were reported. 3. Significant differences in gender were found. Men had more disturbances in sleep than women owing to difficulty in falling a sleep and lack of nocturnal sleep. Women consumed more sleep inducing drugs. Significant increase was reported in napping during the day with increasing age. 4. Significant differences between good sleepers and poor sleepers were found for the following variables : nocturnal sleep time, total sleep time, bed time, sleep onset latency time, sleep latency time after nocturnal awakening, time spent in bed upon arousal, environmental factors, and emotional factors. In conclusion, it was found that the quantity and quality of sleep were significantly altered in hospitalized elderly, but adequate strategies for better sleep were not practiced. Further research is needed to develop Intervention strategies to promote sleep and to prevent sleep problems.

• Journal of Digital Convergence
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• v.13 no.12
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• pp.143-149
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• 2015

This study aims to analyze the predict capability of some of the popular software NHPP reliability models(Goel-Okumo model, delayed S-shaped reliability model and Rayleigh distribution model). The predict capability analysis will be on two key factors, one pertaining to the degree of fitment on available failure data and the other for its prediction capability. Estimation of parameters for each model was used maximum likelihood estimation using first 80% of the failure data. Comparison of predict capability of models selected by validating against the last 20% of the available failure data. Through this study, findings can be used as priori information for the administrator to analyze the failure of software.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4B
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• pp.298-307
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• 2002

This paper concentrates on developing and analyzing an advanced space-time multiuser receiver for WCDMA forward link. Through exploring the interference caused by co-channel users and delayed multipaths in CDMA, a constrained linear adaptive filter is adopted to cancel the interference. Furthermore, by utilizing the space-time diversity, an optimum diversity receiver, called a constrained adaptive space-time interference canceller (C-ASTIC), is proposed. For comparison, the statistical analysis of multiuser performance for WCDMA system with space-time diversity is described. The result of the simulation showed that C-ASTIC performs better than both the space-time diversity combining maximal ratio combiner (MRC) and the single-antenna adaptive interference canceller in a multipath fading channel. Also, the efficiency of the C-ASTIC in the multimedia communication environment is investigated under the multiuser, multi-transmit antenna, and multirate WCDMA system in a multipath fading channel. From the results, the C-ASTIC was validated to be useful for multi-rate WCDMA system through improving the performance gain by more than 3 dB at BER of 10$\^$-3/ in a half or more loaded system.

• 대한공업교육학회지
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• v.33 no.1
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• pp.233-248
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• 2008

Stream Control Transmission Protocol(SCTP) is a new transport protocol that is known to provide improved performance than Transmission Control Protocol(TCP) in multi-homing environment that is having two and more IP addresses. But currently single-homed computer is used primarily that is having one IP address. To identify whether mean transfer time for SCTP is faster that for TCP in single-homed environment considering packet loss, we make up real testbed regulating the bandwidth, delay time and packet loss rate on router and observe the transfer time. We write server and client applications to measure SCTP and TCP mean transfer time by C language. Analysis of these experimental results from the testbed implementation shows that mean transfer time of SCTP is not better than performance of TCP in single homed environment exceptional case. Main reasons of performance are that SCTP compared to TCP stops transmitting data by timeout and data transmission is often delayed when SACK congestion happens. The result of study shows that elaborate performance tuning is required in developing a new SCTP module or using a implemented SCTP module.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.1
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• pp.31-37
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• 2011

Recently gantry-type robot with 3 axes rectangular coordinates have been studied in the many industrial production equipment and machinery fields. To acquire a good handling and motion performance of this robot, reducing the settling-time and securing the accurate-transfer positioning under high-speed conditions should be required. However when robot is moved in high-speed, the large inertia of robot can lead to serious vibration of robot's head. The time-delayed control characteristics of this robot can also lead to tracking error. In this research, the analysis of the effects of higher order positional-profile is carried out to assure high-speed performance and stiffness specifications. To remove the residual vibration caused by kinematic coupling effect of dual-servo gantry, we develop a dual-servo gantry of rotary type that moving frame of x-axis rotates about z-axis. In order to decrease the tracking error, the 3 type lead-filter through system identification was applied respectively. From the experimental results, it was shown that zero-order series leader-filter has the best performance about tracking error and settling time.

• Journal of Trauma and Injury
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• v.33 no.2
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• pp.96-103
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• 2020

Purpose: In patients with trauma, rhabdomyolysis (RM) can lead to fatal complications resulting from muscle damage. Thus, RM must be immediately diagnosed and treated to prevent complications. Creatine kinase (CK) is the most sensitive marker for diagnosing RM. However, relying on CK tests may result in delayed treatment, as it takes approximately 1 hour to obtain CK blood test results. Hence, this study investigated whether the neutrophil-to-lymphocyte ratio (NLR) could predict RM at an earlier time point in patients with trauma, since NLR results can be obtained within 10 minutes. Methods: This retrospective study included 130 patients with severe trauma who were admitted to the emergency room of a tertiary institution between January 2017 and April 2020. RM was defined as a CK level ≥1,000 U/L at the time of arrival. Patients with severe trauma were categorized into non-RM and RM groups, and their characteristics and blood test results were analyzed. Statistical analysis was performed using SPSS version 26.0 for Windows. Results: Of the 130 patients with severe trauma, 50 presented with RM. In the multivariate analysis, the NLR (odds ratio [OR], 1.252; 95% confidence interval [CI], 1.130-1.386), pH level (OR, 0.006; 95% CI, 0.000-0.198), presence of acute kidney injury (OR, 3.009; 95% CI, 1.140-7.941), and extremity Abbreviated Injury Scale score (OR, 1.819; 95% CI, 1.111-2.980) significantly differed between the non-RM and RM groups. A receiver operating characteristic analysis revealed that a cut-off NLR value of 3.64 was the best for predicting RM. Conclusions: In patients with trauma, the NLR at the time of arrival at the hospital is a useful biochemical marker for predicting RM.

• Korean System Dynamics Review
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• v.4 no.2
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• pp.95-130
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• 2003

The purpose of this study is to find what causes make public projects hold off, going beyond the planned deadline and budget. Using System Dynamics(SD) and their derivative Urban Dynamics(UD) models, it intends to analyze major feedback loops based on VENSIM and to simulate them with STELLA software, all of which are interrelated with various causes of project delay. To prevent or ameliorate project delay, first of all it advises to focus on endogenous delaying factors not exogenous ones. These factors either reinforce or balance certain loops in complex causal structure, In the case example on the Cremation Building Project in Cheongju, Residents’ participation demand make negotiation put off and delayed negotiation reinforces administrative-expediency planning in order to observe a time limit, on the other hand, once building consensus, it increase both the level of planning performance and public trust. In the meantime, the real planning process used to neglect residents opinions and manage public grievance only through compensation, he a result of simulation, visible fruit of negotiation in the initial phase seems to be not satisfactory owing to funds and time consumed, but after reaching an mutual agreement among stakeholders, planning performance is effective and strategic than administrative-expediency planning viewed in both financial and time angle. It proposes to devise specific tools schematizing project implementation. In order to upgrade the quality of project management, it recommends for planners to adopt key concepts based on SD/UD diagrams and causal loops, which would contribute to enriching Planning abbots.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.316.3-317
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• 2002

In previous reports, we exhibited that acteoside showed significant cytotoxicity against various cancer cells. In this study we investigated that acteoside is capable of inducing differentiation in HL -60 human leukemia cell line. After being treated with acteoside, the growth curve was decreased remakably in a dose- and time-dependent manner, and cell doubling time was delayed. Exposure of cells to 20 $\mu\textrm{g}$/m$\ell$ acteoside induced differentiation of HL-60 cells to monocyte/macrophage-like cells by cell surface antigen expression. The percentage of NBT reducing activity was increased in a time-dependent manner. In addition. the protein lever of p21 and p16 increased and ppRb decreased in western biot analysis. Theas results suggest that acleoside possess the activity of inducing differentiation in HL-60 cells.

• Journal of Ecology and Environment
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• v.32 no.4
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• pp.221-227
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• 2009

This study describes time lag responses between hydrological variables and phytoplankton biomass in a regulated river system, the lower Nakdong River in South Korea. The lower Nakdong is a typical flow-controlled lotic system, and its limnological characteristics are influenced by climatic variation such as monsoons and summer typhoons. Mean rainfall in the area during summer is about 1,200 mm, which comprises >60% of annual rainfall. Our results show that the regulation of flow in the Nakdong by multi-purpose dams from 1995 to 2004 affected phytoplankton dynamics. Diatom blooms occurred in winter, when the limited discharge allowed for proliferation of the phytoplankton community. Using multiple regression analysis, we detected significant time-delayed relationships between hydrological variables and phytoplankton biomass. These results may be useful for water resource managers, and suggest that 'smart flow' control would improve water quality in large regulated river systems of the Republic of Korea.