• Kyungpook Mathematical Journal
• /
• 제58권2호
• /
• pp.203-219
• /
• 2018

This paper is devoted to the study of strongly ${\alpha}-semicommutative$ rings, a generalization of strongly semicommutative and ${\alpha}-rigid$ rings. Although the n-by-n upper triangular matrix ring over any ring with identity is not strongly ${\bar{\alpha}}-semicommutative$ for $n{\geq}2$, we show that a special subring of the upper triangular matrix ring over a reduced ring is strongly ${\bar{\alpha}}-semicommutative$ under some additional conditions. Moreover, it is shown that if R is strongly ${\alpha}-semicommutative$ with ${\alpha}(1)=1$ and S is a domain, then the Dorroh extension D of R by S is strongly ${\bar{\alpha}}-semicommutative$.

• 국제물리치료학회지
• /
• 제10권2호
• /
• pp.1750-1755
• /
• 2019

Background: Most of the previous researches on the abnormality of breathing pattern have focused on the silence of functional movements owing to such abnormality, however, have not been clearly identified the relationship between the abnormal breathing pattern on one hand and kinesiophobia and flexion relaxation phenomenon (FRP) on the other hand. Objective: To compare patients with chronic low back pain (CLBP) and healthy person in the abnormality of breathing pattern, kinesiophobia, and FRP during flexion and extension of the trunk. Design: Case-control study. Methods: The research subjects consisted of a group of 15 healthy adults and another group of 15 patients with CLBP. Capnography was used to measure the endtidal $CO_2$ ($EtCO_2$) and respiratory quotient (RQ). The muscle activity of multifidus and erector spinae of the subjects was measured during flexion and extension of the trunk to identify their FRP. The Nijmegen Questionnaire (NQ) and Tampa Scale of Kinesiophobia (TSK) were utilized to measure their breathing patterns and kinesiophobia, respectively. The Kolmogorov-Smirnov (K-S) test was conducted in order to analyze the normal distribution of the measured data. Their general characteristics were identified by the descriptive statistics and the independent t-test was performed to identify the differences between the two groups in terms of abnormality of breathing pattern, kinesiophobia, and FRP. The level of significance was set at ${\alpha}=.05$. Results: The patients with CLBP had significantly less $EtCO_2$ and shorter breathing hold time (BHT) than normal healthy person (p<.05). The patient with CLBP also had significantly greater kinesiophobia than healthy person (p<.05), and had less FRP than the healthy person (p<.01). Conclusions: These results suggest that the CLBP had greater abnormality of breathing pattern and kinesiophobia with less FRP than healthy person.

• 한국환경농학회지
• /
• 제20권1호
• /
• pp.28-33
• /
• 2001

본 시험에서 사용된 상추는 대조구인 양액과 양액에 30 mM $KNO_3$, 혹은 양액에 50 mM $KNO_3$를 첨가한 염류농도가 다른 3가지의 양액에서 재배하였으며 이들 양액의 EC는 각각 1.0, 4.5, 6.5 ds/m이었다. 상추의 생육은 처리간에 차이를 보였으며 $KNO_3$를 첨가하여 염류농도를 높여준 용액에서 재배한 상추는 잎끝이 마르는 생리적 장해를 보이면서 발아율의 감소는 물론 초장, 경태, 엽장 및 엽폭 등 성장이 대조구와 비교하여 현저히 부진하였다. 이들 양액에서 자란 상추의 뿌리로부터 마이크로솜을 분리하여 ATPase의 특성을 조사하였다. 마이크로솜 ATPase의 활성은 대조구에 비하여 양액에 30 mM $KNO_3$와 50 mM $KNO_3$를 첨가한 용액에서 자란 상추에서 더 높았다. 상추뿌리로부터 분리한 마이크로솜 ATPase의 총활성은 재배양액 조건에 관계없이 pH 7.0에서 최대로 나타났다. ATPase의 활성은 반응용액의 $K^+$ 농도를 증가시키면 증가하였고 반응용액에 $Na^+$ 농도를 증가시키면 감소하였다. $K^+$에 의한 활성증가 효과는 양액에서 재배한 대조구보다 $KNO_3$를 첨가하여 EC를 높여준 양액에서 재배한 상추뿌리의 마이크로솜 ATPase에서 더 크게 나타났다. 이러한 결과는 생육환경내 $KNO_3$ 농도의 증가에 따라 뿌리의 생리활성을 조절하는 ATPase의 활성이 증가함을 보여준다.

• 국제물리치료학회지
• /
• 제9권1호
• /
• pp.1381-1386
• /
• 2018

The purpose of this study is to investigate the effect of pelvic, Lumbar spine and Cervical spine manipulation on the joint position sense in normal adults. Thirty normal adults were divided into an experimental group of 15 subjects and a control group of 15 subjects. The experimental group was treated with pelvic, Lumbar spine and Cervical spine manipulation with massage, whereas the control group received only massage. Both groups were evaluated in terms of joint position errors (JPEs) using a digital dual clinometer before and after the experiment. The comparison of the JPEs of the experimental group and the control group before and after the experiment showed that the experimental group's cervical spine results were significantly different in the flexion, left lateral flexion, and right rotation (p < .05) and lumbar spine results were significantly different in the flexion and extension (p < .05), but the control group's results were not statistically significant in all items (p > .05). The pelvic, lumbar spine and cervical spine manipulation makes an effect on the joint position sense in normal adults. The findings of this study suggest that the pelvis, lumbar spine and cervical spine manipulation improve the motor ability in people with low joint position sense.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제13권7호
• /
• pp.3671-3689
• /
• 2019

Software defined networking brings unique security risks such as control plane saturation attack while enhancing the performance of wireless sensor networks. The attack is a new type of distributed denial of service (DDoS) attack, which is easy to launch. However, it is difficult to detect and hard to defend. In response to this, the attack threat model is discussed firstly, and then a DDoS attack prevention extension, called FuzzyGuard, is proposed. In FuzzyGuard, a control network with both the protection of data flow and the convergence of attack flow is constructed in the data plane by using the idea of independent routing control flow. Then, the attack detection is implemented by fuzzy inference method to output the current security state of the network. Different probabilistic suppression modes are adopted subsequently to deal with the attack flow to cost-effectively reduce the impact of the attack on the network. The prototype is implemented on SDN-WISE and the simulation experiment is carried out. The evaluation results show that FuzzyGuard could effectively protect the normal forwarding of data flow in the attacked state and has a good defensive effect on the control plane saturation attack with lower resource requirements.

• 대한의용생체공학회:의공학회지
• /
• 제36권6호
• /
• pp.276-282
• /
• 2015

Recently, during the multi-level fusion with pedicle screws, interspinous spacer are sometimes substituted for the most superior level of the fusion in an attempt to reduce the number of fusion level and likelihood of degeneration process at the adjacent level. In this study, a finite element (FE) study was performed to assess biomechanical efficacies of the interspinous spacer combined with posterior lumbar fusion with a previously-validated 3-dimensional FE model of the intact lumbar spine (L1-S1). The post-operative models were made by modifying the intact model to simulate the implantation of interspinous spacer and pedicle screws at the L3-4 and L4-5. Four different configurations of the post-op model were considered: (1) a normal spinal model; (2) Type 1, one-level fusion using posterior pedicle screws at the L4-5; (3) Type 2, two-level (L3-5) fusion; (4) Type 3, Type 1 plus Coflex$^{TM}$ at the L3-4. hybrid protocol (intact: 10 Nm) with a compressive follower load of 400N were used to flex, extend, axially rotate and laterally bend the FE model. As compared to the intact model, Type 2 showed the greatest increase in Range of motion (ROM) at the adjacent level (L2-3), followed Type 3, and Type 1 depending on the loading type. At L3-4, ROM of Type 2 was reduced by 34~56% regardless of loading mode, as compared to decrease of 55% in Type 3 only in extension. In case of normal bone strength model (Type 3_Normal), PVMS at the process and the pedicle remained less than 20% of their yield strengths regardless of loading, except in extension (about 35%). However, for the osteoporotic model (Type 3_Osteoporotic), it reached up to 56% in extension indicating increased susceptibility to fracture. This study suggested that substitution of the superior level fusion with the interspinous spacer in multi-level fusion may be able to offer similar biomechanical outcome and stability while reducing likelihood of adjacent level degeneration.

• 제어로봇시스템학회논문지
• /
• 제15권2호
• /
• pp.163-168
• /
• 2009

In this study, we would be developed the fuzzy controlled PGO that controlled the flexion and the extension of each PGO's hip joint using the bio-signal and FSR sensor. The PGO driving system is to couple the right and left sides of the orthosis by specially designed hip joints and pelvic section. This driving system consists of the orthosis, sensor, control system. An air supply system of muscle is composed of an air compressor, 2-way solenoid valve (MAC, USA), accumulator, pressure sensor. Role of this system provide air muscle with the compressed air at hip joint constantly. According to output signal of EMG sensor and foot sensor, air muscles and assists the flexion of hip joint during PGO gait. As a results, the maximum hip flexion angles of RGO's gait and PGO's gait were about $16^{\circ}\;and\;57^{\circ}$ respectively. The maximum angle of flexion/extention in hip joint of the patients during RGO's gait are smaller than normal gait, because of the step length of them shoes a little bit. But maximum angle of flexion/extention in hip joint of the patients during PGO's gait are larger than normal gait.

• 대한전기학회논문지
• /
• 제33권8호
• /
• pp.299-309
• /
• 1984

This paper proposes the adapter for interrupting capacity augmentation of circuit breaker which can be applied in case of shortage in a existing circuit breaker's interrupting capacity due to utility system extension. The adapter utilizes two winding type of reactor instead of single winding type of reactor and the control of 2ry circuit is excuted by a triac interlocked with the system protective relays actuation so as to cut out the reactor by short circuit of the 2ry winding in normal situation and to cut in the reactor by open circuit of the 2ry winding in abnomal situation such as short circuit accident. As a result of the theoritical analysis and experiment, it is proved that the adaptor can reduce the voltage crop and iron loss due to the reactor signigicantly in normal system condition and do a role of reactor upon the power system accident.

• 천문학회지
• /
• 제37권5호
• /
• pp.501-507
• /
• 2004

The uniquely large dimensions of Giant radio galaxies (GRGs) make it possible to probe for stringent limits on total energy content, Faraday rotation, Alfven speeds, particle transport and radiation loss times. All of these quantities are more stringently limited or specified for GRG's than in more 'normal' FRII radio sources. I discuss how both global and detailed analyses of GRG's lead to constraints on the CR electron acceleration mechanisms in GRG's and by extension in all FRII radio sources. The properties of GRG's appear to rule out large scale Fermi-type shock acceleration. The plasma parameters in these systems set up conditions that are favorable for magnetic reconnection, or some other very efficient process of conversion of magnetic to particle energy. We conclude that whatever mechanism operates in GRG's is probably the primary extragalactic CR acceleration mechanism in the Universe.

• 한국산학기술학회논문지
• /
• 제11권11호
• /
• pp.4346-4353
• /
• 2010

본 연구의 목적은 20대의 정상 성인에서 경부의 관절가동범위와 마사지 및 정적 스트레칭이 관절가동범위에 미치는 영향을 측정하는 것이다. 근골격계와 신경계의 질환이 없는 100명(마사지그룹=50, 스트레칭그룹=50)을 대상으로 실시하였다. 마사지와 정적 스트레칭은 흉쇄유돌근, 사각근, 승모근, 반극근, 판상근, 후두하근, 다열근과 회선근에 적용되었다. 두 그룹은 주 3회의 중재를 받았다. 중재 시간은 10분이었다. 마사지그룹은 경찰법, 유날법 및 스트라이핑 마사지가 사용되었고, 스트레칭그룹은 정적 스트레칭이 사용되었다. 경부의 가동범위 측정도구는 경부의 8가지 동작(후두하 굽힘과 폄, 경부의 굽힘과 폄, 왼쪽 옆굽힘과 오른쪽 옆굽힘, 왼쪽 돌림과 오른쪽 돌림)을 분석하기 위하여 사용되었다. 통계학적 분석결과는 다음과 같다. 첫째, 정상적인 경부의 관절가동범위는 남자에서 후두하굽힘과 폄이 $2.39^{\circ}$와 38.36^{\circ}$, 경부의 굽힘과 폄이 $54.11^{\circ}$와 69.39^{\circ}$, 왼쪽과 오른쪽의 옆굽힘이 $43.50^{\circ}$와 $41.28^{\circ}$, 왼쪽과 오른쪽의 돌림이 $66.39^{\circ}$와 $65.94^{\circ}$로 나타났고, 여자에서는 후두하 굽힘과 폄이 $5.14^{\circ}$와 $36.47^{\circ}$, 경부의 굽힘과 폄이 $55.92^{\circ}$와 $71.22^{\circ}$, 왼쪽과 오른쪽의 옆굽힘이 $43.34^{\circ}$와 $41.06^{\circ}$, 왼쪽과 오른쪽의 돌림이 $69.38^{\circ}$와 $68.63^{\circ}$로 나타났다. 둘째, 후두하 굽힘, 왼쪽 돌림과 오른쪽 돌림에서 여성이 남성보다 더 높은 관절가동범위를 보였다(p<0.05). 셋째, 마사지군과 스트레칭군은 치료 후에 모든 항목에서 관절가동범위의 증가를 보였지만 두 그룹간의 비교에서는 유의한 차이를 보이지 않았다(p<0.05). 위의 결과는 마사지와 정적 스트레칭이 경부 근육의 신장 및 이완을 통해 가동범위를 증가시키는 적당한 방법이라는 것을 제시한다. 그리고 경부의 가동범위를 조사하는 연구의 기초로 제공될 수 있을 것이다.