• PNF and Movement
• /
• v.7 no.4
• /
• pp.31-36
• /
• 2009

Many daily activities require people to complete a motor task while walking. Substantial gait decrements during simultaneous attention to a variety of cognitive tasks have been shown by a group of severely injured neurological patients of mixed etiology. And previous studies have shown that the attentional load of a walking-associated task increased with its level of difficulty. The purpose of this study was to analyze subjects' gait changes are affected by the effects of arithmetic task difficulty and performance level. Participants performed a walking task alone, three different Arithmetic tasks while seated, and among them, two kinds of the simillar Arithmetic tasks in combination with walking. Reaction time and accuracy were recorded for two of the Arithmetic tasks. The mean values of the gait were measured using a Timed Up and Go test among 11 with post-stroke patients while walking with and without forward counting (WFC) and backward counting(WBC).There was significant Arithmetic Task Difficulty level between the 10-forward counting task condition(FC) and the 10-backward counting task condition(BC)(p=0.008). The mean values of T.U.G time were significantly higher under backward counting dual-task condition than during a simple walking task(p=0.009) and WFC(p=0.009). The change in T.U.G time during WFC was higher when compared with the change during a simple walking, but there was no significant difference (p=0.246). This study suggesting that a high interference could be linked with a high level of difficulty, whereas adaptive task enabled participants to perfectly share their attention between two concurrent tasks. Future research should determine whether dual task training can reduce gait decrements in dual task situations in people after stroke. And the dual-task-based exercise program is feasible and beneficial for improving walking ability in subjects with stroke.

• Communications of the Korean Mathematical Society
• /
• v.32 no.2
• /
• pp.233-260
• /
• 2017

Let R be a factorial domain. In this work we investigate the connections between the arithmetic of Int(R) (i.e., the ring of integer-valued polynomials over R) and its monadic submonoids (i.e., monoids of the form {$g{\in}Int(R){\mid}g{\mid}_{Int(R)}f^k$ for some $k{\in}{\mathbb{N}}_0$} for some nonzero $f{\in}Int(R)$). Since every monadic submonoid of Int(R) is a Krull monoid it is possible to describe the arithmetic of these monoids in terms of their divisor-class group. We give an explicit description of these divisor-class groups in several situations and provide a few techniques that can be used to determine them. As an application we show that there are strong connections between Int(R) and its monadic submonoids. If $R={\mathbb{Z}}$ or more generally if R has sufficiently many "nice" atoms, then we prove that the infinitude of the elasticity and the tame degree of Int(R) can be explained by using the structure of monadic submonoids of Int(R).

• The Journal of Korean Academy of Prosthodontics
• /
• v.35 no.1
• /
• pp.31-42
• /
• 1997

This study was performed to investigate the surface roughness of the Cerec Vita Mark II polished by various polishing techniques, compare with that of the Vintage enamel porcelain glazed by high temperature glazing technique. All of the Cerec specimen were finished with sequential use of high speed diamond burs(grit 45, 30 and $15{\mu}m$). The groups were divided into 5 groups : Group I : Cerec Vita Mark II block specimens polished with Sof-lex discs. Group II : Cerce Vita Mark II block specimens polished with Two Striper MPS. Group III : Cerce Vita Mark II block specimens polished with Enhance. Group IV : Cerce Vita Mark II block specimens polished with Porcelain laminate polishing FG kit. Group V : Vintage enamel porcelain glazed by high temperature glazing Technique. Each group was consisted of 10 specimens. The surfaces produced were examined quantitatively using a laser specular reflectance machine(Perthen RM600-s, Feinpruf Perthen GmbH., Germany) and qualitatively under SEM(JSM-5400, JEOL, Japan). The Results were as follows : 1. The arithmetic mean roughness value(Ra) in groups 1, 2, 3 and 4 was higher than that of group5. There was statistically significant difference(P<0.05). 2. The arithmetic mean roughness value(Ra) decreased in the following orders : group 1, group 2, group 4, group 3 and there was no statistically significant difference between group 1 and group 2, group 3, and group 4. There was statistically significant difference among group 1, 2, and group 3, 4 and group 5(P<0.05). 3. The maximum individual peak-to-valley-height(Rmax) decreased in the following orders : group 2, group 1, group 4, group 3, group 5 and there was no statistically significant difference between group 1 and 2, group 1 and group 4, group 3 and group 5. There was statistically significant difference among group 1, 2, and group 1, 4 and group 3, 5(P<0.05). 4. The treated surfaces of group 5 had smoother surface than that of groups 1, 2, 3, 4 with SEM.

• Proceedings of the IEEK Conference
• /
• 2004.08c
• /
• pp.636-639
• /
• 2004

In present, there are many methods such as DCT, Wavelet Transform, or Quantization -to the image compression field, but the basic image compression method have based on DCT. The representative thing of the efficient techniques for information compression is DCT method. It is more superior than other information conversion method. It is widely applied in digital signal processing field and MPEG and JPEG which are selected as basis algorithm for an image compression by the international standardization group. It is general that DCT is consisted of using multiplier with main arithmetic blocks having many arithmetic amounts. But, the use of multiplier requires many areas when hardware is embodied, and there is fault that the processing speed is low. In this paper, we designed the hardware module that could run high-speed operation using row-column separation calculation method and Chen algorithm by distributed arithmetic method using ROM table instead of multiplier for design DCT module of high speed.

• Journal of Gifted/Talented Education
• /
• v.7 no.1
• /
• pp.51-76
• /
• 1997

The purpose of this study was to investigate the effects of Structure of Intellect( SOI) program for children. To achieve this purpose, 81 second grade children were sampled in a elementary school located In Seoul-city and randomly assigned to the experimental group and control group The SO1 training program were treated to the experimental group for 10 weeks, and the 'Thinking Abilities Test developed by Korea Creativity Research Institute were administered to them for pre-test and post-test. The collected data were analyzed by t-test for comparing the group means of experimental group and control group 'I'he results of this study were as follows : Firstly ere were statistically significant differences between experimental group and control group on the post-test scores of arithmetic[t(79)=2.73p,< .01] and visual memory[t(79)-3.68,p <.001]. The mean scores of experimental group(M=8.63) u ere higher than that of control group(Mz7.34) on arithmetic, and the mean scores to experimental group(M=16.68) were higher than that of control group(M=15 32) on visual memory Secondly there were no statistically significant differences between experimental group and control group on the post-test scores of logistic thinking abilities[t(79)=0.22, p>.05] and abstract thinking abilities[t(79)-0.22, p>.051. Thirdly, the post-test scores of visual memory and logical thinking abilities were more increased in the low intelligence group than the high intelligence group. This result showed that the SO1 program were more effective for the low intelligence group. Fourthly, the post-test scores of visual memory and logical thinking abilities were more increased in the low achievement group than the high achievement group. This result showed that the SO1 program were more effective for the low achievement group.

• Korean Journal of Mathematics
• /
• v.26 no.2
• /
• pp.167-174
• /
• 2018

By acting the dihedral group $D_k$ on the set of k-tuple multi-partitions, we introduce k-gonal partitions for all positive integers k. We give generating functions for these new partition functions and investigate their arithmetic properties.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.2576-2578
• /
• 2001

Elliptic curve cryptosystems based on discrete logarithm problem in the group of points of an elliptic curve defined over a finite field. The discrete logarithm in an elliptic curve group appears to be more difficult than discrete logarithm problem in other groups while using the relatively small key size. An implementation of elliptic curve cryptosystems needs finite field arithmetic computation. Hence finite field arithmetic modules must require less hardware resources to archive high performance computation. In this paper, a new architecture of finite field multiplier using conversion scheme of normal basis representation into polynomial basis representation is discussed. Proposed architecture provides less resources and lower complexity than conventional bit serial multiplier using normal basis representation. This architecture has synthesized using synopsys FPGA express successfully.

• Journal of Oriental Neuropsychiatry
• /
• v.20 no.1
• /
• pp.165-176
• /
• 2009

Objectives : The purpose of this study was to assess the effects of mental stress stimulation and acupucnture applied at HT7 point on heart rate variability (HRV) in normal subjects. Methods : Thirty seven healthy volunteers participated in this study. The volunteers were randomly allocated into two groups. Both groups performed a mental arithmetic stress test and stroop color-word test for 10 minute. Then, acupuncture needles were inserted on HT7 for the study group and on non-acupucnture point for the control group. HRV was recorded three times at test time and before and after acupuncture stimulation. Results : After giving mental stress stimulation to both groups, LF and LF!HF ratio were increased and HF was decreased significantly. After giving acupuncture to study group, LF and LF/HF ratio were decreased and HF was increased, but it was not significant. After giving acupuncture to control group, LF and LF/HF ratio were increased and HF was decreased, but it was not significant. Conclusions : This results show that mental arithmetic stress test and stroop color-word test contribute to activation of the sympathetic nervous system Acupuncture at HT7 could be relatively useful to decrease sympathetic activity and balance autonomic nervous system for those who are under stress.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.22 no.1
• /
• pp.42-51
• /
• 2012

Objectives: To compare the exposure level of extremely low frequency (ELF) magnetic fields among semiconductor workers, shipyard welders and office workers. Methods: To measure the ELF magnetic field concentration, EMDEX LITE (Enertech, USA) were used and monitored for eight hours continuously. Five companies handling the electric and magnetic field (EMF) source were investigated, which the exposure groups were classified into three groups: semiconductor workers, welders, and office workers. Welder group was chosen as a high exposed group and office group as a low exposed group. Results: The arithmetic mean (${\pm}SD$) and geometric mean (GSD) of personal exposure level of semiconductor workers were 0.73 (${\pm}1.33$) ${\mu}T$, 0.43 (2.88) ${\mu}T$, respectively. The ceiling value ranged between 0.18 and 123.2 ${\mu}T$. Welders were exposed high with the arithmetic mean value of 3.46 (${\pm}\;13.46$) ${\mu}T$ and geometric mean value of 0.45 (4.70) ${\mu}T$, respectively, and ceiling value range of 75.5~129.6 ${\mu}T$. The exposure levels of office workers were low compared to other exposed groups; the arithmetic mean 0.05 (${\pm}0.13$) ${\mu}T$, geometric mean 0.03 (2.38) ${\mu}T$ and ceiling value range 0.37~3.35 ${\mu}T$. This study revealed statistically significant differences of the mean ELF magnetic field exposure doses among three groups (p < 0.01). Conclusions: The average ELF magnetic field exposure doses of semiconductor workers were much higher than those of office workers in control group, but were lower than those of welders in high exposure group.

• Bulletin of the Korean Mathematical Society
• /
• v.54 no.6
• /
• pp.2141-2147
• /
• 2017

Let G be a finite group and m a divisor of ${\mid}G{\mid}$. We prove that G has at least ${\tau}(m)$ cyclic subgroups whose orders divide m, where ${\tau}(m)$ is the number of divisors of m.