• Physical Therapy Korea
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• v.28 no.2
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• pp.154-160
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• 2021

Background: Theoretically, balance is affected by the height of center of mass (COM) during quiet standing. However, no one examined this in humans with variables derived from the center of pressure (COP). Objects: We have conducted balance experiment to measure COP data during quiet standing, in order to examine how the COP measures were affected by the height of COM, vision, floor conditions, and gender. Methods: Twenty individuals stood still with feet together and arms at sides for 30 seconds on a force plate. Trials were acquired with three COM heights: 1% increased or decreased, and not changed, with two vision conditions: eyes closed (EC) and eyes open (EO), and with two floor conditions: unstable (foam pad) and stable (force plate) floor. Outcome variables included the mean distance, root mean square distance, total excursion, mean velocity, and 95% confidence circle area. Results: All outcome variables were associated with the COM height (p < 0.0005), vision (p < 0.0005), and floor condition (p < 0.003). The mean velocity and 95% confidence circle area were 5.7% and 21.8% greater, respectively, in raised COM than in lowered COM (24.6 versus 23.2 mm/s; 1,013.4 versus 832.3 mm²). However, there were no interactions between the COM height and vision condition (p > 0.096), and between the COM height and floor condition (p > 0.183) for all outcome variables. Furthermore, there was no gender difference in all outcome variables (p > 0.186). Conclusion: Balance was affected by the change of COM height induced by a weight belt in human. However, the effect was not affected by vision or floor condition. Our results should inform the design of balance exercise program to improve the outcome of the balance training.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.301-310
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• 2010

Bacillus subtilis strains produce a broad spectrum of bioactive peptides. The lipopeptide surfactin belongs to one well-known class, which includes amphiphilic membrane-active biosurfactants and peptide antibiotics. Both the srfA promoter and the ComP-ComA signal transduction system are an important part of the factor that results in the production of surfactin. Bs-M49, obtained by means of low-energy ion implantation in wild-type Bs-916, produced significantly lower levels of surfactin, and had no obvious effects against R. solani. Occasionally, we found strain Bs-M49 decreased spore formation and the development of competence. Blast comparison of the sequences from Bs-916 and M49 indicate that there is no difference in the srfA operon promoter PsrfA, but there are differences in the coding sequence of the comA gene. These differences result in three missense mutations within the M49 ComA protein. RT-PCR analyses results showed that the expression levels of selected genes involved in competence and sporulation in both the wild-type Bs-916 and mutant M49 strains were significantly different. When we integrated the comA ORF into the chromosome of M49 at the amyE locus, M49 restored hemolytic activity and antifungal activity. Then, HPLC analyses results also showed the comA-complemented strain had a similar ability to produce surf actin with wild-type strain Bs-916. These data suggested that the mutation of three key amino acids in ComA greatly affected the biological activity of Bacillus subtilis. ComA protein 3D structure prediction and motif search prediction indicated that ComA has two obvious motifs common to response regulator proteins, which are the N-terminal response regulator receiver motif and the C-terminal helix-turn-helix motif. The three residues in the ComA N-terminal portion may be involved in phosphorylation activation mechanism. These structural prediction results implicate that three mutated residues in the ComA protein may play an important role in the formation of a salt-bridge to the phosphoryl group keeping active conformation to subsequent regulation of the expression of downstream genes.

• Journal of the Korean Data and Information Science Society
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• v.13 no.1
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• pp.17-23
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• 2002

Microsoft's component technology, COM, is introduced and a COM object for generating distribution numbers is implement ed. Examples using the object in various language environments are given. A strategy for statistical software development using components is discussed.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.441-443
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• 2011

OSEK COM은 OSEK/VDX에서 제안한 자동차 ECU의 태스크 간 통신 규약이다. 본 논문에서는 OSEK COM의 규약을 준수하는 내부 통신을 위한 메시지 송수신 메커니즘을 제시한다. 제시한 메커니즘의 타당성을 검토하기 위하여 ARM 프로세서가 탑재된 EZ-AT7에서 태스크 간의 정상적인 내부 통신 동작 상태를 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.21-23
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• 2011

OSEK/VDX COM은 자동차 ECU의 통신을 위해 OSEK/VDX에서 제안한 통신 규약이다. 본 논문에서는 OSEK/VDX COM의 내부 통신 메커니즘을 설계한다. 설계한 메커니즘의 타당성을 검증하기 위해 ARM7 프로세서가 장착된 임베디드 개발 보드 EZ-AT7를 이용하여 ECU 내부의 태스크간의 통신의 정상적인 동작을 확인 하였다.

• JOURNAL OF ELECTRICAL WORLD
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• no.9 s.81
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• pp.31-35
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• 1983

• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.147-158
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• 2008

The purpose of this study was to analyze the kinematical variables involved in two types of service motion in tennis pinpoint and platform stance, to find the fastest serving method. Seven skilled high school tennis players participated, and the kinematics were recorded by the Vicon motion analysis system. For the gathering and analysis of the data workstation, bodybuilder and polygon were used. During the back swing for the pinpoint stance, as the back leg moves forward the COM and the racquet moves more, thus taking 0.04 seconds longer than the platform stance. The body of the subject takes a bow-shape as the subject's foot moves back and their hip moves forward. This movement enables the subject to create more power during the backswing to impact. It also increases the spread of the COM racquet and the serve speed is increase. As there is no forward movement of the foot during the backswing of the platform stance, the COM and the racquet move less and thus the time required is shorter than that for the pinpoint stance by 0.04seconds. Similarly, the time spent creating the power for the serve is shortened, the COM racquet is narrower and the speed is lessened. However, the advantage of this serve is that it increases the stability.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.1
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• pp.93-99
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• 2014

PURPOSE: The purpose of this study was to compare three dimensional displacement and peak velocity of the center of mass (COM) during obstacle crossing in young and older adults. METHODS: 10 young adults (6 males/4 females, $24.6{\pm}1.9$ years, age range: 22.0-26.9) and 10 older adults (1 male/9 females, $76.9{\pm}5.1$ years, age range: 65.2-81.2) participated in the study. Both groups crossed an obstacle, which is 10% of leg length, and COM was measured using motion analysis system. Independent t-test was used to find significant differences between two groups. RESULTS: The older adults showed significantly greater and faster COM displacement and peak velocity in mediolateral (M-L) direction as compared with young adults (p<.01 and p<.001 respectively). However, the young adults showed significantly greater and faster COM displacement and peak velocity in anteroposterior (A-P) direction as compared with older adults (p<.05 and p<.001 respectively). Furthermore, the young adults showed faster peak velocity of COM in vertical direction as compared with older adults (p<.001). However, no significant difference was found in the COM displacement in vertical direction between two groups. CONCLUSION: Greater and faster COM displacement and peak velocity in M-L direction in older adults were due to compensatory adjustment for appropriate contact on base of support of swing limb. Thus, the motion of the COM in M-L direction may be a crucial factor to identify risk of falls in older adults.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.241-246
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• 2010

Field experiments were carried out to establish economic threshold for com borer (Ostrinia furnacalis (Guen$\'{e}$e)) on waxy com plants by examining the number of adult insects caught in pheromone traps and the injury levels of waxy com which were artificially controlled. Adult com borers were lured into the pheromone traps during the whole growth period in five areas in Gangwon province including Chuncheon. The number of com borers trapped was the greatest in Chuncheon followed by Cheolwon and Hongcheon, and the same trend was observed for injury level of waxy com. Based on marketable yield data of waxy com plants related to the artificially-controlled injury levels at tassel stage, spray threshold was determined as the injury level of 11~15%, where the injury of com plants exceeded the economically admitting level.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.5
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• pp.427-431
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• 1995

This study was carried out to investigatigate feed cost of com-manure silage and growth performance of Korean native goats which was fed com-manure silage. The average weight about 11.6 kg of twenty one Korean native male goats (4 months used to determine the effect of the feeding trial. The goats were individually reared in metabolism cages and fed diet daily of 2% of the body weight on the dry matter basis. The treatments were divided into whole crop com silage(CS silage), whole crop com ensiled with cage layer manure (CLM; Com-manure silage or MS silage) and whole crop com silage supplemented with urea at feeding time (US silage). The content of crude protein, lactic acid and the ratio of ammonia nitrogen to total nitrogen ($NH_3-N/Total$ N) in MS silage were increased from 7.7 to 14.9%, 5.7 to 7.5% and 8.2 to 16.6%, and the differences were significantly (p < 0.05) different in all observations. Total body weight gain of those goats for 90 days was 6.0 kg (66.7 g/day; MS silage 4.3 kg (47.8 g/day; US silage) and 3.9 kg (43.4 g/day; CS silage), and feed conversion of MS silage (5.98) for 90 days was increased by far the best in the other groups and decreased about 30% in proportion to CS silage. Feed cost per 1 kg MS silage (1,606 won) was the lowest (p < 0.05) in the body weight gain and cut down expenses than fed CS silage by 37% of feed cost.