• Korean Journal of Applied Biomechanics
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• v.17 no.2
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• pp.1-9
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• 2007

Walking is not only an essential component of the human mobility, but also is a good exercise. Inability to walk freely can reduce an individual's quality of life and independence substantially. Being a relatively low impact activity, walking is particularly good for the elderly and research has shown that regular walking in the elderly reduces the chance of fall-related injuries and mental diseases as well. In spite of the documented benefits of regular walking, it is still difficult to walk without the aid of assistive devices for the frail elderly who have lower extremity problems. Assistive walking devices(AWD), such as crutches, canes, hiking-poles, T-Poles and walkers, are often prescribed to the elderly to make their walking be safe and efficient. Many researchers have demonstrated the effects of AWDs such as reducing lower extremity loading, improved dynamic/gait stability, yet, no study has been done for gait pattern when the elderly gait with AWDs. Therefore, the purpose of this study was to examine whether T-Poles, one of the AWDs, change the elderly gait pattern. Eight community-dwelling female elderly participated in this study. Laboratory kinematics during walking with T-Poles(PW) and with out T-Poles(NPW) was assessed. PW showed significant increase in step width, stride length, gait velocity and decrease in swing time. No significances were found in lower body joint angles but meaningful trend and pattern were found. Maybe the reason was due to the participants. Our participants were healthy enough so that the effect of T-Poles was minimum. PW also showed typical gait phases which are no single support phase during a gait cycle. It indicates that walking with T-Poles may guarantee safe and confident walking to the frail elderly.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.209-215
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• 2007

The purpose of this study was to investigate gait factor and muscle activity depending on hiking poles-using. Eight healthy men volunteered for this experiment. Each of them performed down-hill walking with hiking poles-using and without poles at speed of 3.5km/h for 45 minutes on a treadmill. The treadmill was set 25% down-hill inclination. Kinematic data collected in 60Hz were recorded and analyzed by using 2D motion capture system to measure step time and step length so on. And the lower extremity muscle activities were simultaneously recorded in 1500Hz and assessed by using EMG. The statistical analysis was the paired t-test with repeated measures to compare between hiking poles-using and without poles. The level of statistical significance for all tests was .05. The results of this study were following : Step time was showed statistically different according to pole conditions. That is, the case of poles-using was longer than without poles in step time. Also, step length was showed statistically different between two conditions. Step length about trials with poles was longer than trials without poles. In the muscle activity, the case of all muscles was not showed statistical significance about pole conditions. However, in most muscles IEMG, there were some decreasing-trend relatively when hiking polesusing.

• Journal of applied mathematics & informatics
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• v.40 no.3_4
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• pp.507-513
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• 2022

In this paper, we investigate some results on complex delay-differential equations of the classical Malmquist theorem. A classic illustrations of their results states us that if a complex delay equation w(t + 1) + w(t - 1) = R(t, w) with R(t, w) rational in both arguments admits (concede) a transcendental meromorphic solution of finite order, then deg_wR(t, w) ≤ 2. Development and upgrade of such results are presented in this paper. In addition, Borel exceptional zeros and poles seem to appear in special situations.

• Nonlinear Functional Analysis and Applications
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• v.29 no.3
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• pp.621-633
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• 2024

Let R_n be the space of rational functions with prescribed poles. If r ∈ R_n, does not vanish in |z| < k, then for k = 1 $${\mid}r^{\prime}(z){\mid}{\leq}{\frac{{\mid}B^{\prime}(z){\mid}}{2}}\sup_{z{\in}T}{\mid}r(z){\mid}$$, where B(z) is the Blaschke product. In this paper, we consider a more general class of rational functions rof ∈ R_m*n, defined by (rof)(z) = r(f(z)), where f(z) is a polynomial of degree m^* and prove a more general result of the above inequality for k > 1. We also prove that $$\sup_{z{\in}T}\left[\left|{\frac{r^{*\prime}(f(z)}{B^{\prime}(z)}}\right|+\left|{\frac{r^{\prime}(f(z))}{B^{\prime}(z)}}\right|\right]=\sup_{z{\in}T}\left|{\frac{(rof)(z)}{f^{\prime}(z)}}\right|$$, and as a consequence of this result, we present a generalization of a theorem of O'Hara and Rodriguez for self-inverse polynomials. Finally, we establish a similar result when supremum is replaced by infimum for a rational function which has all its zeros in the unit circle.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.227-235
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• 2009

The purpose of this study was to analyze differences of 45minutes up-hill walking depending on hiking poles and steady walking time. Seven healthy men volunteered for this experiment. Each of them performed up-hill walking with hiking poles and without hiking poles at speed of 3.5km/h during 45minutes on a treadmill. The treadmill was set 25% up-hill inclination. The lower extremity 4 muscles activity including rectus femoris, tibialis anterior, gastrocnemius, biceps femoris was recorded and assessed by using EMG. And Heart rate(HR) and Rating of perceived exertion(RPE) were recorded and analyzed by 15minutes interval. The statistical analysis was two-way ANOVA with repeated measures to compare effects of hiking poles and steady walking time. The level of statistical significance for all tests was P<.05. The results of this study were following : Integrated EMG about four individual muscles doesn't have statistical significancy. However, the sum of IEMG of the four muscles was decreased some with poles than without poles(p<.0l) and IEMG about four muscles was rut different on steady walking time. Second, HR was increased significantly as time up(P<.01). RPE was decreased some with poles than without poles(P<.05) and RPE was increased significantly as time up(P<.01).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.964-967
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• 2002

An internal finishing process by the application of magnetic abrasive machining has been developed as a new technology to obtain a fine inner surface of pipe. In this paper, another method of magnetic abrasive machining in which the N and S magnetic poles are feed and a workpiece is rotated only is tried in a fine-pipe, and its finishing characteristics is experimently investigated by various effective factors such as feeding amplitude. From the experimental results, it is found that the feed effects of magnetic poles on the finishing characteristics are large in internal finishing.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.1
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• pp.8-13
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• 1997

An electric field due to point dipole within conductor-backed thin dielectric layer above the earth is calculated by using saddle point method When the dielectric layer is thin enough to support a cutoff mdoe, we show that the field may be approximated by sum of contributions of branch points of TE mode and poles of tM mode and that the branch points and poles contributions are interpreted as an evanescent lateral waves and leaky waves, respectively.

• Transactions of the KSME C: Technology and Education
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• v.3 no.3
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• pp.217-223
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• 2015

The patterning of microbead in microfluidics channel is a practical technique for application in bio and medical areas. An approach is described for a direct patterning of magnetically active microbeads in microfluidic devices without inner structure. Local magnet arrangements - flat arrangement and stack arrangement - contacting same poles or opposite poles of magnet were utilized for generating trapping magnetic fields. The arrangement of magnets contacting same poles generated isolated patterns by repelling of magnetic field. The flat arrangement of vertically reverse magnet arrays shaped trapping patterns repelling magnetic field line between same poles. Spatially, the stack compositions of magnet arrangements allow diverse isolated trapped patterns of magnetic particles. Trapped magnetic particles in fluidic channels were stable on the $18m{\ell}/hr$ flow conditions and magnetic force of 1.08 mT in the all experiments. This experimental study suggests the simple and versatile methods to pattern magnetic particles, and has potential of wide application to bio and medical area.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.10
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• pp.771-782
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• 1991

In industrial multivariable plants, it is ofte the case that the plant outputs are measured in similar components not simultaneously but serially. In this paper, the problem of estimating the state vector of the plant based on the data obtained from such a measuring scheme is considered, and a special type of observer(referred to as a $'$multiple serial-sampling$'$ type observer) which renews its internal states whenever a new group of data is obtained is proposed. It is proved that such an observer can be constructed for almost every sampling period if the palnt is observable as a continuous-time multivariable system, and that the poles of the closed-loop system using the multiple serial-sampling type observer consist of the poles of the observer and those of the state feedback system. The behaviors of the observer and the closed-loop system are studied by simulation. The results of simulation indicate that a multiple serial-ampling type observer can estimate the state of the plant more accurately than the ordinary type observers and improve the closed-loop performance, especially, in the existence of measuring noise.ng noise.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.14-15
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• 2002

Iron nitride alloy films prepared in the form of laminated ${(Fe_{97}Al_3)}_{85}N_{15}/Al_2O_3$ multilayers (Ml's) due to excellent soft magnetic properties and high saturation magnetization [1, 2] are very promising materials for poles and shields in ultra high density thin film heads. The present work concerns the ferromagnetic (FM) coupling effect as a function of the thickness of $Al_2O_3$ spacers by analysis of the magnetic domain structure.