• Journal of Astronomy and Space Sciences
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• 제31권3호
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• pp.187-197
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• 2014

We have investigated the dynamical stability of the proposed companions orbiting the Algol type short-period eclipsing binary SW Lyncis (Kim et al. 2010). The two candidate companions are of stellar to substellar nature, and were inferred from timing measurements of the system's primary and secondary eclipses. We applied well-tested numerical techniques to accurately integrate the orbits of the two companions and to test for chaotic dynamical behavior. We carried out the stability analysis within a systematic parameter survey varying both the geometries and orientation of the orbits of the companions, as well as their masses. In all our numerical integrations we found that the proposed SW Lyn multi-body system is highly unstable on time-scales on the order of 1000 years. Our results cast doubt on the interpretation that the timing variations are caused by two companions. This work demonstrates that a straightforward dynamical analysis can help to test whether a best-fit companion-based model is a physically viable explanation for measured eclipse timing variations. We conclude that dynamical considerations reveal that the proposed SW Lyncis multi-body system most likely does not exist or the companions have significantly different orbital properties from those conjectured in Kim et al. (2010).

• Safety and Health at Work
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• 제7권3호
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• pp.185-193
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• 2016

Background: Management and workers in small and medium-sized enterprises (SMEs) often find it hard to comprehend the requirements related to controlling risks due to exposure to substances. An intervention study was set up in order to support 45 SMEs in improving the management of the risks of occupational exposure to chemicals, and in using the control banding tool and exposure model Stoffenmanager in this process. Methods: A 2-year intervention study was carried out, in which a mix of individual and collective training and support was offered, and baseline and effect measurements were carried out by means of structured interviews, in order to measure progress made. A seven-phase implementation evolutionary ladder was used for this purpose. Success and failure factors were identified by means of company visits and structured interviews. Results: Most companies clearly moved upwards on the implementation evolutionary ladder; 76% of the companies by at least one phase, and 62% by at least two phases. Success and failure factors were described. Conclusion: Active training and coaching helped the participating companies to improve their chemical risk management, and to avoid making mistakes when using and applying Stoffenmanager. The use of validated tools embedded in a community platform appears to support companies to organize and structure their chemical risk management in a business-wise manner, but much depends upon motivated occupational health and safety (OHS) professionals, management support, and willingness to invest time and means.

• 한국수자원학회논문집
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• 제34권6호
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• pp.745-751
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• 2001

본 연구에서는 난류 흐름 중에서 모래의 침강속도를 PTV를 이용하여 측정하였다. PTV는 영상해석기법을 이용하여 입자를 추적하는 방법으로 흐름 중의 침강속도를 측정할 수 있는 유일한 방법이라 판단된다. 실험은 흐름이 없는 경우와 흐름이 있는 경우로 나누어 실시하였다. 흐름이 없는 경우에 PTV로 측정한 침강속도를 기존문헌과 비교한 결과 잘 일치하여 기법의 타당성을 입증하였다. 흐름이 있는 경우에는 유속이 증가함에 따라 침강속도가 감소하는 것으로 밝혀졌다. 이는 유속이 증가함에 따라 난류강도가 증가하여 난류강도가 침강속도의 감소에 영향을 비치는 것으로 판단된다. 난류강도와 침강속도의 관계를 분석한 결과 마찰속도로 무차원화된 침강속도는 정지유체중일때에 비해 약 40% 감소됨을 알 수 있었다.

• 제어로봇시스템학회논문지
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• 제15권10호
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• pp.1039-1046
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• 2009

In this work, a bilateral control for a master-slave manipulator system which will be used for handling objects contaminated by radioactivity has been addressed. The links of manipulators are driven independently by individual motors installed on the base and the driving torque is transmitted through pre-tensioned tendons. The measurable variables are the positions and rates of master/slave motors. In the consideration of the flexibility of the tendon and available measurements for control, we proposed an optimal static output feedback control for possible bilateral control architecture. By using modal analysis, the system model is reduced to guarantee the detectability which is a necessity for the static output feedback control design. Based on the reduced model, the control gains are determined to attenuate vibration in the sense of optimality. The feasibility of the proposed control design was verified along with some simulation results.

• 대한간호학회지
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• 제28권4호
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• pp.821-831
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• 1998

Management of perimenstrual discomfort could be an effective strategy for women's health promotion. This study was designed to develop and test the nursing intervention program for the reduction of the perimenstrual discomfort. The data were collected from a group of 76 female university students (34 in the intervention group, 42 in the control group) during November 20, 1997 and March 10, 1998. Measurements were taken concerning perimenstrual discomfort, self care behavior, and perimenstrual discomfort from both groups, at pre and post intervention. Intervention program involved education, support, counseling, and relaxation training, via individual and group levels over a twelve-week period. Listed are the summarized results : 1. The intervention group had more knowledge con corning perimenstrual discomfort(t=2.290, p=.025), self care behavior(t=3.198, p=.000), and lower perimenstrual discomfort score (t=-4.446, p=.000) than the control group at post intervention. 2. The intervention group showed an enhancement on the knowledge on perimenstrual discomport (t=2.35, p=.025), and decreased the perimenstrual discomfort score(t=-7.36, p=.000). However change of self care behavior was not significant during the intervention. According to this study a developed nursing intervention program is effective for reduction of the perimenstrual discomfort. For a future research, it is necessary that experiments concerning menstruation, and a correlational study of perimenstrual discomfort and stress ill be performed.

• 대한치과교정학회지
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• 제17권1호
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• pp.73-83
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• 1987

The purpose of this longitudinal study was to examine the growth changes of mandibular symphysis and lower incisors with age. The material was 294 lateral cephalometric radiographs taken longitudinally from 6 to 13 year old children, who were not teated orthodontically. The following conclusions seem to be warranted. 1. The sex difference of the measurements of mandibular symphysis and lower incisors were not statistic ally significant. 2. There were growth increments (2.69mm in boys and 2.08mm in girls) in the total thickness of mandibular symphysis. 3. There were a great change and individual variations on the curvature of anterior border of mandibular symphysis. 4. The chin angle had a tendency to decrease progressively in both sexes. 5. There were growth increments (8.23mm in boys and 7.40mm in girls) in the anterior dental height. 6. The lower anterior teeth tended to incline labially with age.

• 대한치과교정학회지
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• 제8권1호
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• pp.49-58
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• 1978

This investigation was undertaken to know how the bony facial profile could be changed with age. The 5 serial lateral cephalometric roentgenograms of the fourteen boys and fourteen girls between 7 and 11 years of age were studied and the findings seems to warrant the following conclusions. 1. The manaible tended to become more prognathic in relation to the cranial base (S-N) during growth, but the maxilla showed very little change. 2. There was increase in the inclination of the lower border of mandible associated with the increase in mandibular prognathism. 3. There was a tendency to being straight in bony facial profile due to the decrease in angle ANB with age. 4. The chin portion had a tendency to forward and downward growth in relation to the cranial base but there was slight strong tendency in downward growth. 5. The vertical growth was more prominant in the maxilla than in the mandible. 6. There was uniform and gradual increase of all measurements during growth. 7. Dimension of the craniofacial complex was larger in the boys than in the girls but this difference was not statistically significant. 8. Individual variation in skeletal growth was a normal occurrence.

• 마이크로전자및패키징학회지
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• 제20권4호
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• pp.69-74
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• 2013

In this paper, the impact of integrating large number of I/O (Input-Output) and Core power Delivery Network (PDN) on a 6 layers Flip-Chip Ball Grid Array (FCBGA) package is investigated. The impact of core induced supply noise on high-speed I/O interfaces, and high-speed I/O interface's supply noise coupling to adjacent high-speed I/O interfaces' jitter impact are studied. Concurrent stress validation software is used to induce SSO noise on each individual I/O interfaces; and at the same time; periodic noise is introduced from Core PDN into the I/O PDN domain. In order to have the maximum coupling impact, a prototype package is designed to merge the I/O and Core PDN as one while impact on jitter on each I/O interfaces are investigated. In order to understand the impact of the Core to I/O and I/O to I/O noise, the on-die noise measurements were measured and results were compared with the original PDN where each I/O and Core PDN are standalone and isolated are used as a benchmark.

• 천문학회지
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• 제44권3호
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• pp.97-108
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• 2011

The photometric light curves of the W-type W UMa eclipsing contact binary system BB Pegasi have been found to be extremely asymmetric over all the observed 63 years in all wavelengths UBVR. The light curves have been characterized by occultation primary minima. Hence, the morphology of these light curves has been studied in view of these different asymmetric degrees. The system shows a distinct O'Connell effect, as well as depth variation. A 22.96 years of stellar dark spots cycle has been determined for the system. Almost the same cycle (22.78 yr) has been found for the depth variation of MinI and MinII. We also present an analysis of mid-eclipse time measurements of BB Peg. The analysis indicates a period decrement of $5.62{\times}10^{-8}$ day/yr, which can be interpreted in terms of mass transfer at a rate of $-4.38{\times}10^{-8}M_{\odot}$/yr, from the more to the less massive component. The O - C diagram shows a damping sine wave covering two different cycles of 17.0 yr and 12.87 yr with amplitudes equal to 0.0071 and 0.0013 day, respectively. These unequal durations show a non-periodicity which may be explained as a result of magnetic activity cycling variations due to star spots. The obtained characteristics are consistent with similar chromospherically active stars, when applying the Applegate's (1992) mechanism.

• 한국전문물리치료학회지
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• 제3권2호
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• pp.1-7
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• 1996

Two standard methods of cane length measurements were compared to find which methods really achieve the elbow flexion of 20 degrees to 30 degrees Twenty-four patients with hemiplegia who were ambulatory participated in this study. Method I : Length of the cane measured from the floor to the top of the greater trochanter. Method II : Length of the cane measured from the floor to the distal wrist crease with the arm at the side. Using an adjustable cane, each individual was fitted according to the two methods, and elbow angle was measured after each adjustment. The elbow angle according to Method I and Method II was $46.4{\pm}20$, $44.3{\pm}12.2$, respectively. No significant difference was found in the elbow angle or the cane length between the two methods. Of the 24 participants, 5(20.8%) measured according to method I and 3(12.5%) measured according to method II showed the elbow angle between 20 degrees and 30 degrees. These low predictive rates of agreement between ideal cane length and actually achieved elbow angle showed that these two methods which have conventionally been accepted as a standard to measure ideal cane length need to be revised through further research.