• Korean Journal of Applied Biomechanics
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• v.14 no.3
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• pp.203-218
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• 2004

The purpose of this study was to analyze the comparisons of the kinematical variables when performing Yoko Ukemi(side breakfall) by three Stage in Judo. The subjects were four male judokas who were trainees Y. I. University Squad members and the Yoko Ukemi were filmed by two S-VHS 16mm video cameras(60fields/sec.). The selected times were subject to KWON 3D analysis program and kinematical analysis to compare variables of three Yoko Ukemi. Temporal variables(total time-required : TK, TR by each phase), the body part touched order on the mat and COG variables were computed through video analysis while performing right Yoko Ukemi by three stage. From the data analysis and discussion, the following conclusions were drawn : 1. Temporal variables : total time-required(TR) when performing Yoko Ukemi(side breakfall) by each stage, the first stage(full squat posture: FP : 1.11sec.) showed the shortest time, the next was 3rd(Shizenhontai, straight natural posture: NP : 1.41sec.), and 2nd(Jigohontai, straight defensive posture, DP : 1.42sec.), respectively- 2. TR when performing Yoko Ukemi(side breakfall) by each stage, and phase : the first phase(take of phase, average 0.68sec.) showed the longest time, next was the third phase(ukemi phase, 0.39sec.), and the second phase(air phase, 0.23sec.), respectively. 3. When performing yore Ukemi the body part touched order and TR on the mat : hip(0.94sec.) showed the shortest time, the next was elbow hand(0.97sec.), back(0.98sec.), and shoulder(1.04sec.) order. The hip part touched on the mat the first, but slap the mat in order to alleviate the shock try hand palm and forearm before receiving impact (difference 0.03sec,) 4. Vertical COG variables in each event by each stage : e1(ready position, average 78.33cm) moved the highest, the next was e2(jumping position, 70.14cm), e3(transition position, average 64.00cm), e4(landing position, average 35.99cm), and e5(ukemi position, average 18.32cm) order, gradual decrease respectively. And the difference of COG were showed in initial by each stage, because position fo Yoko Ukemi was difference by each stage in preparation position, but in accordance with executing of Ukemi phase that difference of COG was by decreasing, almost equal displacement in e4(landing) and e5(Ukemi)position finally.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.1
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• pp.1-9
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• 2013

This study examined the effects of the occlusal stability and a partial coverage mouthguard on physical fitness and motor capacity to determine the importance of the occlusal stability as a possible action mechanism of mouthguards on physical performance. Twenty physical education students were included for measurements of their handgrip strength, back strength, whole body reaction time, flexibility, sidestep test, stork stand test and jumping test according to the following 5 different occlusal conditions: mouth closed position without a mouthguard, with a full coverage mouthguard, with a right partial coverage mouthguard, with a left partial coverage mouthguard and with anterior partial mouthguard. The results revealed no significant difference in any of the measured physical factors between the occlusal conditions with and without a full-coverage mouthguard. On the other hand, a significant difference was observed in whole body reaction between the occlusal conditions with and without the partial coverage mouthguards. Therefore, isokinetic muscle tests on both knee joints and the Wingate anaerobic power test should be performed under the following five occlusal conditions: with or without full-coverage maxillary custom-made mouthguard, with a unilateral right or left partial-coverage maxillary mouthguard and with an anterior partial-coverage maxillary mouthguard. These results suggest that the partial coverage mouthguard had a short-term beneficial effect on agility rather than full coverage mouthguard.

• Journal of Environmental Impact Assessment
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• v.27 no.2
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• pp.232-239
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• 2018

Our study aims to provide a guideline of deer-proof fence heights to prevent roadkill of water deer (Hydropotes inermis), the most frequently killed by a vehicle collision, in South Korea. With 27 water deer in deer ecology center of the National Institute of Ecology, we measured the ability of water deer to jump gradually higher fences from 0.5cm by 10cm until the deterrence rate reached 100%. Ourresultrevealed that the deterrence rate became 96.7% at the fence height of 1.5m and the rate reached 100% at the 1.8m. We believe that our result provides the fundamental information to prepare a standard of deer-proof fence height. This evidence-based standard will contribute to improving the guideline for wildlife crossing construction and management, established by Ministry of Environment Korea.

• 한국해양학회지
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• v.26 no.1
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• pp.59-66
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• 1991

Laboratory studies were carried out to measure the sound velocity (V/SUB p/) and quality factor (Q/SUB p/, inverse attenuation) in the horizontal (H) and vertical (V) direction on the core sampled sediment of deep-sea basin (1,850 meter water depth), East Sea of Korea (Sea of Japan). Sampled core was about 250 cm long and 500 kHz ultrasonic p-wave transducer was used for a sound soured. V/SUB p/ varies from 1,480 m/sec to 1,500 m/sec, it is not clear which direction is faster, V/SUB PH/ or V/SUB pv/, within${\pm}$ 1.0% anisotropy (A/SUB p/). It is thought because the core sediment facies is highly (or slightly) bioturbated homogeneous mud with very high porosity (more than 80%). The general trend of Q/SUB p/ is decreasing 10 to 5 with the buried depth, it is strongly affected by the variation of sediment texture (increasing silt, decreasing clay) with increasing of CaCO$_3$ and organic matter content, But Q/SUB PH/ is jumping up to 14.9 near the bottom of core sediment as including volcanic ash richly. The relationship between V/SUB PH/ and Q/SUB PH/ shows the mirror image nearly, it is interpreted that not only the geotechnical properties and texture but also sea-water characteristics (high Q/SUB p/, low V/SUB p/) according to rich water content affect strongly in the upper part of the unconsolidated deep-sea basin sediment.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.65-75
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• 2002

The study has a goal that produces abundant documents that needed for athletes to teach and progress skills by analyzing 3-dimensional action analysis of C-difficulties Ring jump included in body original elements among techniques constructing Rhythmic Sport Gymnastics. 1. It was the longest applied time delay that E-3 indicates 0.409${\pm}$0.017sec in each event applied time delay. 2. It was the tallest height that E-3 indicates 88.5${\pm}$1.3% in displacement of body's center. 3. It was the fastest velocity in E-2 where the velocity of left foot is 732.4${\pm}$46.1cm/sec, the velocity of right foot is 1958.4${\pm}$25.1cm/sec. 4. the lowest angle was founded at 97.8 degree in the E-3 on the trunk extension angle. 5. The lowest angle of both sides were seen at 92.8${\pm}$14.9degree and 69.2${\pm}$5.7degree in the E-3 on the each displacement of knee joint. 6. The highest angle of both sides were seen at 171.3${\pm}$6.9degree and 167.9${\pm}$8.4degree in the E-3 on the each displacement of ankle joint As a result of these studies, by jumping with ankle joint extension to accomplish the Ring jump action, it is considered to have the time of flexiblity and staying in the air which we can see in a back.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.81-98
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• 2003

The purpose of this study is to closely examine kinematic characteristics by jump phase of Li Xiaopeng motion in horse vaulting and provide the training data. In doing so, as a result of analyzing kinematic variables through 3-dimensional cinematographic using the high-speed video camera to Li Xiaopeng motion first performed at the men's vault competition at the 14th Busan Asian Games, the following conclusion was obtained. 1. It was indicated that at the post-flight, the increase of flight time and height and twisting rotational velocity has a decisive effect on the increase of twist displacement. And Li Xiaopeng motion showed longer flight time and higher flight height than Ropez motion with the same twist displacement of entire movement. Also the rotational displacement of the trunk at peak of COG was much short of $360^{\circ}$(one rotation) but twist displacement showed $606^{\circ}$. Likewise, Li Xiaopeng motion was indicated to concentrate on twist movement in the early flight. 2. It was indicated that at the landing, Li Xiaopeng motion gets the hip to move back, the trunk to stand up and the horizontal velocity of COG to slow down. This is thought to be the performance of sufficient landing, resulting from large security of rotational displacement of airborne and twist displacement. 3. It was indicated that at the board contact, Li Xiaopeng motion made a rapid rotation uprighting the trunk to recover slowing velocity caused by jumping with the horse in the back, and has already twisted the trunk nearly close to $40^{\circ}$ at board contact. Under the premise that elasticity is generated without the change of the feet contacting the board, it will give an aid to the rotation and twist of pre-flight. Thus, in the round-oH phase, the tap of waist according to the fraction and extension of hip joint and arm push is thought to be very important. 4. It was indicated that at the pre-flight, Li Xiaopeng motion showed bigger movement than the techniques of precedented studies rushing to the horse, and overcomes the concern of relatively low power of jump through the rapid rotation of the trunk. Li Xiaopeng motion secured much twist distance, increased rotational distance with the trunk bent forward, resulting in the effect of rushing to the horse. 5. At horse contact, Li Xiaopeng motion makes a short-time contact, and maintains horse take-off angle close to vertical, contributing to the increase of post-flight time and height. This is thought to be resulted from rapid move toward movement direction along with the rotational velocity of trunk rapidly earned prior to horse contact, and little shave of rotation axis according to twist motion because of effective twist in the same direction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.423-429
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• 2018

Objective: This study was conducted to investigate the effects of WBVE on biomechanical factor analysis of drop landing jumps before and after a four week training program. Methods: Participants were divided into two group: VEG (n=5, age: $25.7{\pm}2.3yrs$, height: $170{\pm}7.6cm$, weight: $69.3{\pm}8.3kg$) and OEG (n=5, age: $24.6{\pm}3.4yrs$, height: $164{\pm}4.9cm$, weight: $58.8{\pm}9.2kg$). Ten infrared cameras (Vicon, UK) with a sampling rate of 100 Hz were used in two GRF measurement systems (AMTI, USA). Results: The variability of the center of mass was largest at the falling phase, and there was a great risk of injury when landing after the jump. Second, the jumping heights of the VEG (vibration exercise group) were higher than those of the OEG (only exercise group), regardless of training period. Third, there were significant differences in the hip joint P1 (flexion) and knee joint P2 (extension) between the exercise groups after 4 weeks of training. However, there were no significant differences among training periods or phases. Conclusion: regardless of training periods, the VEG showed increased jump height compared with the OEG, but the consistency between the jump height and the lower joint power could not be determined.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.1
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• pp.33-41
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• 1996

In order to obtain the most favourable classification system for fishing gears, the problems in the existing systems were investigated and a new system in which the fishing method was adopted as the criterion of classification and the kinds of fishing gears were obtained by exchanging the word method into gear in the fishing methods classified newly for eliminating the problems was established. The new system to which the actual gears are arranged is as follows ; (1)Harvesting gear \circled1Plucking gears : Clamp, Tong, Wrench, etc. \circled2Sweeping gears : Push net, Coral sweep net, etc. \circled3Dredging gears : Hand dredge net, Boat dredge net, etc. (2)Sticking gears \circled1Shot sticking gears : Spear, Sharp plummet, Harpoon, etc. \circled2Pulled sticking gears : Gaff, Comb, Rake, Hook harrow, Jerking hook, etc. \circled3Left sticking gears : Rip - hook set line. (3)Angling gears \circled1Jerky angling gears (a)Single - jerky angling gears : Hand line, Pole line, etc. (b)Multiple - jerky angling gears : squid hook. \circled2Idly angling gears (a)Set angling gears : Set long line. (b)Drifted angling gears : Drift long line, Drift vertical line, etc. \circled3Dragged angling gears : Troll line. (4)Shelter gears : Eel tube, Webfoot - octopus pot, Octopus pot, etc. (5)Attracting gears : Fishing basket. (6)Cutoff gears : Wall, Screen net, Window net, etc. (7)Guiding gears \circled1Horizontally guiding gears : Triangular set net, Elliptic set net, Rectangular set net, Fish weir, etc. \circled2Vertically guiding gears : Pound net. \circled3Deeply guiding gears : Funnel net. (8)Receiving gears \circled1Jumping - fish receiving gears : Fish - receiving scoop net, Fish - receiving raft, etc. \circled2Drifting - fish receiving gears (a)Set drifting - fish receiving gears : Bamboo screen, Pillar stow net, Long stow net, etc. (b)Movable drifting - fish receiving gears : Stow net. (9)Bagging gears \circled1Drag - bagging gears (a)Bottom - drag bagging gears : Bottom otter trawl, Bottom beam trawl, Bottom pair trawl, etc. (b)Midwater - drag gagging gears : Midwater otter trawl, Midwater pair trawl, etc. (c)Surface - drag gagging gears : Anchovy drag net. \circled2Seine - bagging gears (a)Beach - seine bagging gears : Skimming scoop net, Beach seine, etc. (b)Boat - seine bagging gears : Boat seine, Danish seine, etc. \circled3Drive - bagging gears : Drive - in dustpan net, Inner drive - in net, etc. (10)Surrounding gears \circled1Incomplete surrounding gears : Lampara net, Ring net, etc. \circled2Complete surrounding gears : Purse seine, Round haul net, etc. (11)Covering gears \circled1Drop - type covering gears : Wooden cover, Lantern net, etc. \circled2Spread - type covering gears : Cast net. (12)Lifting gears \circled1Wait - lifting gears : Scoop net, Scrape net, etc. \circled2Gatherable lifting gears : Saury lift net, Anchovy lift net, etc. (13)Adherent gears \circled1Gilling gears (a)Set gilling gears : Bottom gill net, Floating gill net. (b)Drifted gilling gears : Drift gill net. (c)Encircled gilling gears : Encircled gill net. (d)Seine - gilling gears : Seining gill net. (e)Dragged gilling gears : Dragged gill net. \circled2Tangling gears (a)Set tangling gears : Double trammel net, Triple trammel net, etc. (b)Encircled tangling gears : Encircled tangle net. (c)Dragged tangling gears : Dragged tangle net. \circled3Restrainting gears (a)Drifted restrainting gears : Pocket net(Gen - type net). (b)Dragged restrainting gears : Dragged pocket net. (14)Sucking gears : Fish pumps.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7B
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• pp.679-689
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• 2006

Delivering multicast stream is one of the cost-saving approach in the large scale VOD environment. Because implementing VCR-like interactions for user's convenience in the multicast streaming system involves complex problems, we need the proper solutions for them. In this paper, we propose a hybrid scheme which uses the general P2P and the patching scheme with the Collaborative Interaction Streaming Scheme(CISS). CISS provides jumping functionability to the appropriate multicast session after VCR-like interaction in the environment in which multiple peers transmit VCR-like interaction streams to the VCR-like functionability request node to reduce the loads generated by frequent join or departure of peers at the multicast tree during providing VCR-like functionability. Therefore, with the proposed scheme we can distribute network traffic and reduce control overhead and latency. And to evaluate the performance of proposed scheme we compare it in the aspect of the performance of streaming delivery topology, control overhead and streaming quality with P2Cast[10] and DSL[11]. The simulation result shows that proposed P2Patching reduces about 30% of process overhead and enhances about $25{\sim}30%$ of streaming quality compared with DSL.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.1-19
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• 2008

This research is to analyze the force on landing 3 Type of Halfpipe Curves(Ellipse, Circle, Brachistochrone) based on the mechanical calculation of normal force on a sloping surface. Jumping off a platform on a bard horizontal surface, the flexing of the legs, the softness of the snow, the angle of the landing surface, initial velocity and the forward motion of the snowboarder can contribute to reducing the force on landing. But halfpipe is significantly determined by the curvature of surface. It is definitely verified that the Brachistochrone curve is more safety than others. However currently using the Ellipse curve is mostly safe too. If we consider the efficiency of construction, we can easily think there is no use of another curves except normal ellipse curved halfpipe. It would better that geometrically verity curved halfpipe should be designed for improving fluent skills to snowboarders. This methode of research can be a model of scientifical research on sports safety how can sportsman reduce critical injury by designing optimal halfpipe facilities and manual.