• Journal of muscle and joint health
• /
• v.14 no.2
• /
• pp.109-117
• /
• 2007

Purpose: The purpose of the study was to identify the effect of a self-exercise program on low back pain, abdominal-back muscle strength and waist flexibility in hospital nurses. Method: An experimental research design was employed. 43 subjects (20 in the experimental group and 23 in the control group) who worked in a general hospital in W city agreed to participate in this study. The intervention had 6 sessions with self-exercise program including flexion and extension demonstrated by a trained research assistant. A Visual Analog Scale was used to measure the subjective pain severity. Abdominal-back muscle strength was measured with a back strength dynamometer, while waist flexibility was gauged by the standing of the subject's upper body. Analysis included descriptive statistics, $x^2$ test, t-test and ANOVA. Result: The experimental group exhibited significantly decreased low back pain, an increase in abdominal-back muscle strength, and increased waist flexibility after 6 sessions. The experimental group were not significantly increased in abdominal-back muscle strength than the control group. Conclusion: These results suggest that further research is needed to replicate for verification of clinical validity with the methodological rigors, and to utilize the self-exercise program for care and prevention of low back pain.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.11
• /
• pp.833-839
• /
• 2002

As the demand for slim laptops requires low-height optical disc drives, vibration problems of optical disc drives are of great concern. Additionally, with the decrease of a track width and a depth of focus in high density drives, studies on vibration resonance between mechanical parts become more important. From the vibration point of view, the performance of optical disc drives is closely related with the relative displacement between a disc and an objective lens which is controlled by servo mechanism. In other words, to read and write data properly, the relative displacement between an optical disc and an objective lens should be within a certain limit. The relative displacement is dependent on not only an anti-vibration mechanism design but also servo control capability. Good servo controls can make compensation for poor mechanisms, and vice versa. In a usual development process, robustness of the anti-vibration mechanism is always verified with the servo control of an objective lens. Engineers partially modify servo gain margin in case of a data reading error. This modification cannot correct the data reading error occasionally and the mechanism should be redesigned more robustly. Therefore it is necessary to verify a mechanism with respect to the possible servo gain plot. In this study we propose the experimental verification method for anti-vibration mechanism with respect to the existing servo gain plot. Thismethod verifies axial vibration characteristics of optical disc drives on the basis of transmissibility. Using this method, we verified our mechanism and modified the mechanism for better anti-vibration characteristics.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.9
• /
• pp.2210-2220
• /
• 2009

Independent-suspension type axles for heavy duty special vehicles are usually produced by only a few specialized companies. The special techniques, such as designing, producing, testing techniques has been unveiled. The test of durability with the vehicle in which is installed a prototype taking several years is required for setting the designing parameters. In this research, through-drive the core-component of the independent-suspension type axle has been tested with the reverse engineering and the testing methods for the confirmation of the accomplishment in the development goal has been suggested. Also the prototype is developed from designing and testing the design with the CAD and CAE tools. As a result, the process and testing methods studied in this research are useful in the development of power train.

• Journal of KIISE:Software and Applications
• /
• v.29 no.7
• /
• pp.450-464
• /
• 2002

Many modern complex systems, including most object-oriented systems, have dynamic characteristics that their components are dynamical]y configured during run-time. However, few analysis techniques are available that consider the dynamic nature of systems explicitly. We propose a specification and analysis method for these dynamic systems. We design a new temporal logic, called HDTL, to specify the properties of dynamically evolving systems, and tune up the tableau method for this logic. HDTL incorporates variables and quantifiers that enable the automatic analysis. Using HDTL and the analysis method, we can specify the correctness requirements of systems and check whether the system actually agree with the requirements or not. An experiment shows that HDTL is suitable for specifying dynamic properties and the analysis technique works well.

• The Journal of Industrial Distribution & Business
• /
• v.10 no.4
• /
• pp.67-76
• /
• 2019

Purpose - This study attempted to construct and validate a structural model of the relationship between the quality of medical services, perceived risk, reputation and customer satisfaction, which is the main concept of the relationship between large hospitals as well as small and medium hospitals and medical consumers. Through this verification, the small and medium hospitals are to find the way for wise coping in competitive situation with large hospitals. Research design, data, and methodology - This research developed a hypothesis by constructing a structural equation that reaches the satisfaction and the relationship between reputation of perceived risk and perceived risk of service quality perceptions of customers of small and medium hospitals. Research data were collected through a questionnaire survey of respondents who had medical service experience from small and medium hospital. A total data of 252 respondents were used as the sample for the final analysis and analyzed using SPSS 23.0 and AMOS 23. Results - As a result, the relationship of quality of medical service, reputation, and customer satisfaction among small and medium hospitals was consistent with the results of precedent studies, and the perceived risk has a significant impact on reputation, so the greater the perceived risk, the higher the preference for reputable medical institutions as large hospitals. In addition, it was found that the direct route from perceived risk to customer satisfaction was not significant, and reputation was found to have a full mediating effect on perceived risk and customer satisfaction. Customers who use small and medium hospitals prefer to use reputable medical institutions if their perceived risk is high, which is different from risk perception when specific targets are specified. Conclusions - In terms of the effect from customer satisfaction, not only the path of perceived risk → reputation → customer satisfaction, but also the quality of service quality → reputation → customer satisfaction. These findings suggest that small and medium hospitals are appropriately responding to competition with large hospitals, rather than focusing on the perceived risks and reputation of customers in establishing and utilizing competitive strategies to create new customers and preserve existing customers.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.14 no.1
• /
• pp.117-124
• /
• 2010

Different to other social infrastructures, bridge elements or bridges can be damaged or collapsed and this may cause death toll and severe social and economical damage, bridges should be managed to maintain a safety level. Diverse strengthening methods is developed to improve a deteriorated bridge performance up to original design level. But rational decision-making process and methodologies to select a optimum strengthening method are absence yet in Korea. This paper therefore derived items and proposed methodologies for quantity estimate considering uncertainty to select a optimum strengthening method among conceptually designed alternatives. And also, to demonstrate the applicability and verification of the proposed approach, it was applied to select the optimum strengthening method for the deteriorated T-shape concrete girder bridge. The model and the procedure can greatly contribute to the uncertainty-oriented alternative selection.

• Journal of Drive and Control
• /
• v.12 no.3
• /
• pp.52-59
• /
• 2015

An electro hydraulic poppet valve (EHPV) and a variable orifice poppet are assembled in a single block, which is referred to as a RHINO but is also generally called a pilot-operated flow control valve. In this study, we analyzed the structure and the operating principle for a RHINO applied in a 21-ton electric excavator system. The RHINO was experimentally tested to measure the dynamic responses and the pressure energy loss. In this test, we investigated the variation in the conductance coefficient according to the increase in the supply pressure under a constant current and a variation in the flow rate according to the increase in the current. Then, the geometrical shapes and the spring stiffness of the RHINO were considered to develop an analysis model. The characteristics (current-force and hysteresis) for the solenoid based on the experimental data were reflected in the analysis model that was developed, and the reliability of the analysis model was also verified by comparing the experimental and analytical results. The developed model is thus considered to be reliable for use in a wide range of applications, including optimum design, sensitivity analysis, parameter tuning, etc.

• Korean Journal of Construction Engineering and Management
• /
• v.21 no.4
• /
• pp.30-37
• /
• 2020

The purpose of this study is to compare and contrast the amount of overseas construction orders of South Korea and China by using various time series models that measure the overseas construction orders. Based on the analysis we propose better specification (model selection) with much more predictive power and prove the universality of the model developed by applying our findings with respect to the prediction power of overseas construction orders from other countries viewpoints (verification of generalization). The input variables include Dubai crude oil and exchange rates by country from 1981 to 2019. The VAR model is proposed based on the prediction power test, with respect to MAPE, RMSE, and MAE between the estimates and actual measurements from 2016 to 2019. We also conclude the results of the prediction of overseas construction orders time series of China are again consistent with the actual numbers. These analyses suggest the possibility of developing a comprehensive model that predict the potential construction orders of other countries.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.11 no.6
• /
• pp.145-154
• /
• 2012

This paper analyzed the characteristics of traffic accidents in all tunnels on nationwide freeways and selected some various independent variables related to accident occurrence in tunnels. The study aims to develop reliable accident forecasting models using the various dependent variables such as the number of accident (no.), no./km, and no./MVK. Finally, reliable multiple linear regression models were proposed in this paper. This study tested the validity verification of developed models through statistics such as $R^2$, F values, multicollinearity, residual analysis. The paper selected the accident forecasting models considering the characteristics of tunnel accidents and two models were finally proposed according to two groups of tunnel length. In the selected models, natural logarithm of ln(no./MVK) is used for the dependent variable and AADT, vertical slope, and tunnel hight are used for the independent variables. The reliability of two models was proved by the comparison analysis between field data and estimating data using RMSE and MAE. These models may be not only effective in evaluating tunnel safety under design and planning phases of tunnel but also useful to reduce traffic accidents in tunnels and to manage the traffic flow of tunnel.

• Korean Journal of Remote Sensing
• /
• v.25 no.2
• /
• pp.107-112
• /
• 2009

A technique for the simulation of various kinds of ground based SAR system was developed. This is an ancillary research for the development of an ArcSAR system which uses an arc-rail as a platform for the antenna movement instead of linear rail. The results of applying conventional Deramp FFT based SAR focusing algorithm to the simulated raw signal of linear rail type ground based SAR for the point targets showed that the developed simulation technique generated accurate GB-SAR raw signal. The developed technique is now being used for the development and verification of SAR focusing algorithm for the arc-rail type ground based SAR. The simulation technique is also expected to be very useful for the purpose oriented system design and operation planning of ground based SAR technique.