• The Journal of the Acoustical Society of Korea
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• v.43 no.4
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• pp.455-465
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• 2024

In shallow water, the array invariant, known as the effective range estimation method, is developed based on the broadband dispersion characteristics in an ideal waveguide, which can be summarized by the waveguide invariant. It is robust enough to estimate both the array tilt and range simultaneously, even in situations where array tilt exists. Recently, it has been extended to fully consider the angle dependence of the waveguide invariant. However, applying the array invariant in range-dependent environments instead of range-independent environments can lead to range estimation errors due to bathymetry mismatch. In this paper, we interpret such range estimation errors by introducing the concept of effective range. Through numerical simulations and experimental data in a weakly range-dependent environment, we demonstrate the relationship between range estimation errors and effective range.

• PNF and Movement
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• v.7 no.4
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• pp.1-7
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• 2009

Purpose : This paper reviews on the method of PNF stretching. Methods : This is literature study with Pubmed, medline, SPORT Discus, EBSCO, ProQuest and books. Results : PNF stretching is effective for increasing range of motion than static and ballistic stretching. CR(contract-relax) technique is effective and CRAC(contract-relax with agonist contraction) technique including agonist contraction is more effective. A minimum of one repetition, twice or three times per week is required for range of motion gains, needs to be conducted continueously. A minimum of 20% contraction intensity and more than 3 seconds contraction duration are needed to increase range of motion. Inclusion of static stretching of antagonist and agonist contraction is more effective. Conclusions : PNF stretching is more effective for increasing range of motion than other stretching methods, but, clinicians need to select proper techniques according to subjects and muscles, and conduct carefully when applying technique.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.2
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• pp.118-123
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• 2011

This study aims to investigate stereotype and effective cue presentation methods for burner-control relationship of four-stove range for Korean. A total of 381 subjects(male : 262, female : 119) were surveyed using questionnaire, in which eight gas range models drawn by 3-D Max 2010 were presented. The gas range models were labeled by signs(☆#${\triangle}{\square}$) to eliminate suggestive effect of sequential codes such as alphabets and numbers. The results showed that the stereotype was significantly affected by occupation(p < 0.10), but not by subjects' gender and age(p > 0.39). The stereotype of four-burner gas range for Korean was the same as that of Chinese, while the stereotype was different from that of American. The cues with rectangular-shaped arrangements identical or similar to those of burners were effective to relate burners to corresponding controls. The diamond-shaped cues and burner arrangements were not appropriate for representing burner-control relationship of four-stove gas range. These findings would be used as a basic guideline when designing four-burner gas range or similar equipments.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.4
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• pp.136-144
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• 1997

The characteristics of fatigue crack growth subject to out-of-plane bending fatigue are studied in terms of crack opening behavior by using pre-cracked smooth specimens. Crack opening stress is measured by an elastic compliance method which may precisely and continuously provide many date using strain gages during experiment. The results of the short crack and the long crack arranged by crack closure concept show that the effective stress gange ratio of short crack is grester than that of long crack, and ano- malous growth behavior of short crack may be elucidated by the variation of crack opening stress. When the variation of fatigue crack growth rate is arranged versus effective stress intensity factor range. Iinear relation is held also for the short crack. It shows that growth behavior of short crack can be quantitatively represent- ed by the fracture mechanics parameter using effective stress intensity factor range.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.11
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• pp.361-368
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• 2015

In AAGFCS the effective range is regarded as a range for the bullet's speed exceeding the speed of sound to damage the stationary target. Hence the real engagement range might be extended over the effective range for the approaching target since bullet's relative speed to the target increases depending on the approaching speed. However previous TOF equations have good computation accuracy within the effective range only, and they can not be used above that range due to their bad accuracy. We propose an accurate TOF computation method which can be used both within and above the effective range in real time. Some simulation results are shown to demonstrate usefulness of our algorithm for the 30mm projectile.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.183-190
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• 2000

Effective range of Hydraulic Hammer Compaction was studied by numerical analysis instead of empirical method. Numerical analyses were carried out with commercial FEM code, ABAQUS, and verified by comparing the numerical results with field tests of Hydraulic Hammer Compaction. Most of material properties were evaluated by data from laboratory and in-situ tests. Vertical effective range was estimated by distribution curve of plastic strain energy dissipated through soil layers under dynamic load and these results were in good agreement with field tests. Based on verification, the effects of governing properties of Hydraulic Hammer Compaction such as number of hit can be determined by numerical analyses. In addition, vertical effective range can also be determined by Menard's empirical equation using the external work at converging time of plastic strain energy in numerical analysis. This implies that the minimum energy of Hydraulic Hammer Compaction for improvement can be determined by Menard's equation.

• Journal of muscle and joint health
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• v.2 no.2
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• pp.147-159
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• 1995

Although there are many research studies on the effectiveness of heat and cold therapy for patients with arthritis at home or health care center, little attention has been paid to determining which therapy associates with season is effective for patients with chronic arthritis. The purpose of this study was to explore the effectiveness of heat and cold therapy associated with season for patients with arthritis. An experimental design using replications with intervention was employed. A total of 27 female arthritic patients were selected. Data were collected in summer and winter. Hot bag and ice bag were applied on each patient's knee for each 20 minutes alternatively. Joint pain, discomfort and range of motion were measured. Data were analyzed using paired t-test, and two-way ANOVA. The results of this study were ; 1. Joint pain Heat therapy was effective for pain relief, as compared with cold therapy. Heat therapy was more effective for pain relief in winter than in summer. Cold therapy was effective for pain relief, but there was no statistically significant difference of pain relief between summer and winter. 2. Discomfort Discomfort was decreased using heat therapy, whereas it was increased using cold therapy. Although discomfort was decreased using heat therapy in both summer and winter, there was no statistically significant difference of discomfort between summer and winter. Using cold therapy, discomfort was decreased in summer, but increased in winter. and season had effect on discomfort. 3. Range of motion Although there was no statistically significant difference between the range of motion for both heat and cold therapy, range of motion was Increased using both heat and cold therapy. In winter, range of motion was increased rather than in summer by using heat therapy. Using cold therapy, The range of motion was decreased in both summer and winter. There was no stastistically significant difference of range of motion between heat therapy and cold therapy. Furthermore, there was no statistically significant difference of range of motion between summer and winter. In conclusion, both heat and cold therapy were effective for pain relief, discomfort, and range of motion, especially heat therapy. Heat therapy was effective for pain relief, discomfort, and range of motion in winter, as compared with summer. Cold therapy, however, was effective for only pain relief in winter, The findings suggest the use of heat therapy for patients with arthritis especially in winter.

• Journal of the Optical Society of Korea
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• v.20 no.5
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• pp.628-632
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• 2016

We studied experimentally and theoretically the vertical range of the confined electric field in the gap area of metamaterials, which was analyzed for various gap widths using terahertz time-domain spectroscopy. We measured the resonant frequency as a function of the thickness of poly(methyl methacrylate) in the range 0 to 3.2 μm to quantify the effective detection volumes. We found that the effective vertical range of the metamaterial is determined by the size of the gap width. The vertical range was found to decrease as the gap width of the metamaterial decreases, whereas the sensitivity is enhanced as the gap width decreases due to the highly concentrated electric field. Our experimental findings are in good agreement with the finite-difference time-domain simulation results. Finally, a numerical expression was obtained for the vertical range as a function of the gap width. This expression is expected to be very useful for optimizing the sensing efficiency.

• Journal of Biomedical Engineering Research
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• v.36 no.3
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• pp.69-78
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• 2015

Ultrasonic physiotherapy systems should comply with IEC 60601-2-5(particular requirements for safety of ultrasonic physiotherapy equipment) standard for safety of patients and clinical performances. One of the most important parameters in the standard is the effective radiating area ($A_{ER}$). It has to be measured in accordance with IEC 61689 (field specifications and methods of measurement in the frequency range 0.5MHz to 5MHz). Typical ultrasonic physiotherapy system works in the frequency range 1MHz ~ 3MHz to comply with the IEC 61689. However, ultrasonic physiotherapy system using frequencies over 5MHz is out of the IEC 61689's scope. That is, even if such ultrasonic physiotherapy systems are developed by demands of the market, there is no standard to apply. It is the motivation for this study. Whereas there are other parameters to be considered, this study focuses on the effective radiating area and shows effectiveness of applying IEC 61689 in measuring effective radiating area of ultrasonic physiotherapy systems using frequency range over 5MHz by comparing the results of computer simulation and experiment. Results of this study shows that applying the IEC 61689 standard to ultrasonic physiotherapy system using frequency range over 5MHz is possible.

• Physical Therapy Korea
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• v.12 no.2
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• pp.28-36
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• 2005

The purpose of this study was to investigate the effects of the increasing ankle range motion program on ambulation and balance for the elderly with balance disorder. Eighteen elderly subjects were administered with a timed test twice; approximately 4 weeks apart. The exercise group participated in a fall prevention exercise class at the Y.S. Senior Welfare Center of the Seoul Metropolitan Government. The session consisted of a stationary cycle, static stretching ankle joints, balance boards, and progressive resistive exercises using the Thera-band. The results were as follows: Firstly, the increasing ankle range of motion program was effective on the exercise group. Gait-speed was improved (p<.005). Secondly, balance was significantly improved (p<.000). Thirdly, increasing ankle range of motion program was effective in ankle dorsiflexion which was the major risk factor for falls among the elderly. Differences in gait and balance between the groups were examined using a paired t-test (p<.05). The exercise group demonstrated significantly higher values of gait-speed, ankle range of motion, and balance when compared with the non-exercise group. The results of this study suggest that the increasing ankle range of motion program is an effective intervention for the elderly with balance disorder.