• Advances in Energy Research
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• v.7 no.1
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• pp.1-19
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• 2020

Energy consumption of air-conditioning and refrigeration systems is responsible for about 25 to 30% of the energy demand especially in hot seasons. This equipment is mostly electricity dependent and their use in principle affects negatively the environment. Enhancing the energy efficiency of the existing equipment is important as one of the measures to reduce environment impacts. This paper reports the results of an experimental study to evaluate the impacts of the use electronic expansion valve and variable velocity compressor on the performance of vapor compression refrigeration system. The experimental rig is composed of two independent circuits one for the vapor compression system and the other is the secondary fluid system. The vapor compression system is composed of a forced air condenser unit, evaporator, hermetic compressor and expansion elements, while the secondary system has a pump for circulating the secondary fluid, and an air conditioning heat exchanger. The manufacturer's data was used to determine the optimal points of operation of the system and consequently tests were done to evaluate the influence of variation of the compressor velocity and the opening of the expansion device on the performance of the refrigeration system. A fuzzy logic model was developed to control the rotational velocity of the compressor and the thermal load. Fuzzy control model was made in LabVIEW software with the objective of improving the system performance, stability and energy saving. The results showed that the use of fuzzy logic as a form of control strategy resulted in a better energy efficiency.

• The Journal of Korean Physical Therapy
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• v.27 no.3
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• pp.147-153
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• 2015

Purpose: The purpose was to determine whether the application of the abdominal drawing-in maneuver (ADIM) and abdominal expansion maneuver (AEM) to stroke patients would affects their trunk stability, balance, pulmonary function, and grip strength. Methods: The subjects were 36 stroke patients who were randomly and equally assigned to an ADIM group (n=12), an AEM group (n=12), and a control group (n=12). The intervention was applied to each group three times per week, 30 minutes each time, for four weeks. Outcome measures were grip strength, modified functional reach test (mFRT) and pulmonary function. Pulmonary function were measured force expiratory volume at one second (FEV1), forced vital capacity (FVC), FEV1/FVC and peak expiratory flow (PEF) values. Results: The results of the three groups showed statistically significant improvements in grip strength. The AEM group showed significantly greater differences in grip strength than either the ADIM group or the control group. In the anterior mFRT, the ADIM group showed significantly improvements than the control group. The ADIM and AEM groups were showed statistically significant greater improvements in PEF between the baseline and post-intervention and the post-analysis revealed that the AEM group showed significantly greater improvements than the control group. Conclusion: The results of this study indicate that the ADIM and AEM were effective in improving the PEF of pulmonary function. The ADIM was more effective than AEM in trunk stabilization.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.8 no.1
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• pp.44-48
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• 1997

Anatomic and physiological changes of the larynx with advancing age result in morphologic changes of the vocal fold and reduced control of the phonatory mechanism in elderly individuals and are reflected in increased unstability of fundamental frequency (Fo). The purpose of this study is to increase current understanding of acoustic and stroboscopic characteristics of normal elderly persons voices. First, phonated /a/ vowel productions by 40 normal adults (20 to 40 years, 20 men and 20 women) and 40 normal elderly persons (60 to 80 years,20 men and 20 women) were analyzed, using CSL (model 4300B) acoustic analysis software, to obtain acoustic measures related to fundamental frequency stability nd vocal resonance characteristics. Second, stroboscopic images of the vocal fold behavior in all subjects were analyzed by experienced specialists. In the men, fundamental frequency variation (vFe) (p＜0.01), jitter. (p＜0.05), and shimmer (p＜0.05) for the older group were significantly higher than the value for the adult group. In the stroboscopic findings, edema of vocal fold had a significant finding in aged men (15%). In the women, vFo (p＜0.05), jitter (p＜0.05), and noise to harmonic ratio (NHR) (p＜0.05) for the older group were significantly higher than the value for e adult group and first formant frequency (F1) (p＜0.01) and second formant frequency (F2) (p＜0.01) for. the older group were significantly lower than the value for the adult group. In the stroboscopic findings, vocal fold atrophy had a significant finding in aged women (25%). Frequency stability, as reflected by vFo, jitter, shimmer, and NHR, decreases with advancing age in men and women and spectral analysis of phonated /a/ vowel productions reveals the lowering of the frequency of F1 and second F2 with advancing age, especially in aged women. Change in the mass of vocal folds, due to atrophy or edema, is considered to be the greatest factor in these acoustic changes.

• Physical Therapy Korea
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• v.20 no.3
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• pp.81-88
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• 2013

Active straight-leg raise (ASLR) is a physical evaluation procedure to test lumbar spine stability. Several previous studies have reported various methods to control the activation of abdominal muscles during ASLR. We investigated the effects of three different hip positions in frontal plane on abdominal muscles to increase or decrease the difficulty level of lumbar spine stability exercise during ASLR in pain free subjects. Eleven young and healthy subjects voluntarily participated in this study (6 men, 5 women; mean age=$24.0{\pm}1.2$ years, height=$160.0{\pm}7.3cm$, weight=$55.0{\pm}10.6kg$, body mass index=$21.5{\pm}2.3kg/m^2$). The subjects had three trials on each ASLR with hip $10^{\circ}$ adduction, neutral hip, and hip $30^{\circ}$ abduction. Separate repeated-measures analysis of variance (ANOVA) and the post hoc Bonferroni tests (with ${\alpha}$=.05/3=.017) were performed for each muscle among the three different hip positions in frontal plane (ASLR with hip $10^{\circ}$ adduction, neutral hip, and hip $30^{\circ}$ abduction). The ipsilateral external oblique (EO), contralateral EO, ipsilateral internal oblique/transverse abdominis (IO/TrA), and contralateral IO/TrA were significantly greater in ASLR with hip $30^{\circ}$ abduction compared with ASLR with hip $10^{\circ}$ adduction. Also, the ipsilateral EO, contralateral EO, and ipsilateral IO/TrA were significantly greater in ASLR with hip $30^{\circ}$ abduction compared with ASLR with neutral hip. These results suggest that ASLR with hip $30^{\circ}$ abduction and neutral would be useful method to strengthen the EO and IO/TrA. And, ASLR with hip $10^{\circ}$ adduction would be effective in early stages of lumbar stabilization program due to low activation of EO and IO/TrA during maintaining of ASLR position with low load.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.665-676
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• 2013

The present study analyzed the KOCCA's Game Immersion data to explore the relationship between psychological traits and game immersion. Psychological traits were classified into four categories; emotional stability, self-esteem, willpower, and happiness. These were put into the multiple regression analysis as the dependent variables with age, sex (dummy), economic status of the homes, variety of leisure activities, friend and family relationship, and time to play games. Four types of immersion (psychological unstability, bad relationship, interrupted daily lives, and failure to control game time and desire) were put into the multiple regression analysis as the independent variables. The multiple regression analysis indicated that the dependent variables predicted the game immersion. Among the psychological traits emotional stability was the strongest factor (negative) that influences the game immersion. Next powerful indicator (negative) among the psychological traits was self-esteem. Based on the findings, measures to alleviate the problems of game immersion and ideas for further research were suggested.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.2
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• pp.243-249
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• 2015

To improve stability of the water resources that were seriously affected by climate change and various environmental effects and to supply the clean water always, continuous efforts are essential. Provision of measures with respect of hardware is basically essential to improve the water resources stability due to the topographic characteristic in Korea. However, building a new dam becomes gradually very difficult because of a hardship in selecting right places, opposition forces such as environment and local residents, negative publicity for large civil engineering projects, and so on. The present study, therefore, proposes the Blue dam as an alternative for securing the water resources of a new concept considering domestic conditions. To evaluate the effect of the Blue dam, the Hec-ResSim model is used and the probabilistic discharge flow rate is applied. As a result, when Dam Yeongcheon is applied as a study area, securing water resources of 14 million tons are predicted be secured and the flood control of 15.4 million tons is expected, in comparison with operation of the existing dam only. Consequently, Blue dams are supposed to carry out the function of securing water resources, controling flood, maintaining eco-environmental instream flow, generating hydroelectric power, and providing spaces for recreational activities.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.973-984
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• 2017

There is a growing need to apply TBM tunnelling method for the construction of underground facilities such as subways and utility tunnels in urban areas. Due to the variability and uncertainty of the ground, tunnelling in urban areas has various safety hazards which could cause damage to people and properties and it is very costly to recover from accidents. Therefore, it is very important to identify hazards from the planning and design phase and to establish risk mitigation measures. In this study, a total of 31 hazards affecting the stability of TBM tunnelling works in urban areas were listed from both the technical literature and correspondence with experts in tunnelling area. The importance and priorities of the hazards were analyzed by conducting Delphi technique, which is a decision-making method by consensus among experts. Finally, 12 hazards that satisfy the content validity criteria were settled and could be used as major control factors for accident prevention during TBM tunnelling works.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.10 no.1
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• pp.15-22
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• 2012

Purpose : We investigated the effects of the combined use of FES and over ground walking with partial body-weight support (PBWS) on walking function and balance control in people with chronic strokes. Methods : Twenty-seven people who were ambulatory after chronic strokes were evaluated. The exercise's intervention consisted of the combined use of FES and over ground walking with PBWS and general exercise groups. The FES + PBWS group and general exercise group consisted on a-20-minute session per day, 3 times a week during a 4 week period. The evaluation was carried out before, after, and two weeks after the exercise intervention. Outcome measures were a 6 Minute Walk Test, 6-Meter walk Test, Timed Up and Go Test, and a Balance Test, measured before and after the exercise interventions at a-2 week follow up. Results : The endurance was significantly increased in both the FES+PBWS group and general exercise group (p<0.05). Significant increase on the gait velocity was observed in both the FES+PBWS group and general exercise group (p<0.05). The TUG was significantly different in both the FES + PBWS group and general exercise group (p<0.05). However there were no differences in both the between-group & interaction. The stability index was significantly different in both the FES + PBWS group and general exercise group (p<0.05). Conclusion : In conclusion, the combined use of FES and over ground walking with PBWS led to an improvement in walking function and balance control. Thus, it is possible to combine the use of FES and over ground walking with PBWS for physical therapy intervention to improve walking function and balance control. It is suggested to apply this intervention in the clinical field.

• Journal of the Ergonomics Society of Korea
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• v.30 no.2
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• pp.291-296
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• 2011

This study was designed to investigate the effects of an ankle foot orthosis(AFO) with variable ankle joint angles on balance performance in healthy adults. Eighteen healthy adults were recruited in this repeated measures design with subjects as their own controls. An AFO with four kinds of ankle joint angles(-5, 0, 5, and 10 degree) were used and balance performance was measured during single limb standing. Three trials were obtained and then averaged for data analysis. Foot pressure was measured using an F-scan system and muscle activity was measured using an MP150 system. There were significant differences in balance performance with ankle joint angles. An AFO with -5 degrees was associated with significant increases in postural sway(anterior-posterior), and in muscle activity for the medial gastrocnemius and tibialis anterior compared with other degrees of angle. Findings of this study show that angles of an AFO are related to balance performance and a joint angle of 10 degree is effective for promoting joint stability and postural control. This information can be used by clinicians to prescribe AFOs.

• Strategy21
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• s.36
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• pp.150-179
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• 2015

This thesis analyzes Somali piracy as a non-traditional threat to the Sea Lines of Communication (SLOC) and international countermeasures to the piracy. In an era of globally interdependent economies, the protection of sea lines and freedom of navigation are prerequisites for the development of states. Since the post-Cold War began in the early 1990s, ocean piracy has emerged as a significant threat to international trade. For instance, in the Malacca Strait which carries 30 percent of the world's trade volume, losses from failed shipping, insurance, plus other subsequent damages were enormous. Until the mid-2000s, navies and coast guards from Malaysia, Indonesia, Singapore, together with the International Maritime Organization (IMO), conducted anti-piracy operations in the Strait of Malacca. The combined efforts of these three maritime states, through information sharing and with reinforced assets including warships and patrol aircrafts, have successfully made a dent to lower incidents of piracy. Likewise, the United Nations' authorization of multinational forces to operate in Somali waters has pushed interdiction efforts including patrol and escort flotilla support. This along with self-reinforced security measures has successfully helped lower piracy from 75 incidents in 2012 to 15 in 2013. As illustrated, Somali piracy is a direct security threat to the international community and the SLOC which calls for global peacekeeping as a countermeasure. Reconstructing the economy and society to support public safety and stability should be the priority solution. Emphasis should be placed on restoring public peace and jurisdiction for control of piracy as a primary countermeasure.