• 한국전문물리치료학회지
• /
• 제11권3호
• /
• pp.25-32
• /
• 2004

The use of a gym ball is becoming more popular for dynamic balance exercises. However, little is known about the effects of the dynamic ball exercises in the elderly. The purpose of this study was to compare balance and functional mobility after dynamic balance exercises using a gym ball to reduce the risk factorfor falls. All of the 15 subjects were women between the ages of 68 and 91 (mean age=79.9 yrs, SD=5.87) at anursing home in Wonju. Seven of fifteen subjects were placed in the experimental group and the others in the control group. Three clinical tests were used to determine the degree of balance and functional mobility before beginning the exercise program, after 4 weeks of gym ball exercise, and after 8 weeks of gym ball exercise. These three tests included Timed Up & Go (TUG), Berg Balance Scale (BBS) and the Functional Independence Measure (FIM). Dynamic ball exercises training for 8 weeks (5 days per week) included side stretching, prone walking, bridging, marching and opposite arm and leg lifting. There were significant differences found before the gym ball exercise program began and after 4 weeks and then 8 weeks in the experimental group (p<.05). Significant differences between the groups were shown for TUG and BBS (p<.05). No significant difference was noted between the groups for FIM. Therefore, gym ball exercises can improve dynamic balance and may be recommended to include in a therapeutic program to help the elderly reduce their risk of a fall.

• 대한물리치료과학회지
• /
• 제15권3호
• /
• pp.1-8
• /
• 2008

The purpose of this study was to compare the relationship among the Dynamic Gait Index(DGI), Berg Balance Scale(BBS) scores, Timed Up & Go Test(TUG), and subject characteristics. The subjects were fifteen stroke with hemiplegia were chosen in the Konyang University Hospital. Dynamic balance was measured Dynamic Gait Index(DGI), and balance was measured using Berg Balance Scale(BBS). Timed Up & Go Test(TUG) was used to evaluate functional mobility. Data were analyzed using Spearman correlation. There was significant correlated among Dynamic Gait Index(DGI), Berg Balance Scale(BBS) and Timed Up & Go Test(TUG)(p<.01). The correlation among subject characteristics and Dynamic Gait Index(DGI), Berg Balance Scale(BBS), Timed Up & Go Test(TUG) score was significant result in r = -.527 from Dynamic Gait Index(DGI) and pathogenesis(p<.05). There were no significant statistical differences among the types of spasticity and Dynamic Gait Index(DGI), Berg Balance Scale(BBS), Timed Up & Go Test(TUG). The comparison among the sex, type of hemiplegia, pain, pathogenesis and Dynamic Gait Index(DGI), Berg Balance Scale(BBS), Timed Up & Go Test(TUG) score was significant result in pathogenesis(p<.05). The results of this study showed that there was high correlations among the Dynamic Gait Index(DGI) and balance test of people with stroke.

• 대한기계학회논문집A
• /
• 제21권11호
• /
• pp.1950-1956
• /
• 1997

An engineering goal in vibration and noise professionals is to develope quiet machines at the preliminary design stage, and various numerical techniques such as FEM, SEA or BEM are one of the schemes toward the goal. In this paper, the research has been focused on the sensitivity effect of mesh sizes for FEM application so that the optimum size of the mesh that leads to engineering solution within acceptable computing time could be generated. In order to evaluate the mesh size effect, three important parameters have been examined : natural frequencies, number of modes and driving point mobility. First, several lower modes including the fundamental frequency of a 2-D plate structure have been calculated as mesh size changes. Since theoretical values of natural frequencies for a simple structure are known, the deviation between the numerical and theoretical values is obtained as a function of mesh size. The result shows that the error is no longer decreased if the mesh size becomes a quarter wavelength or smaller than that. Second, the mesh size effect is also investigated for the number of modes. For the frequency band up to 1.4 kHz, the structure should have 38 modes in total. As the mesh size reaches to the quarter wavelength, the total count in modes approaches to the same values. Third, a mobility function at the driving point is compared between SEA and FEM result. In SEA application, the mobility function is determined by the modal density and the mass of the structure. It is independent of excitation frequencies. When the mobility function is calculated from a wavelength to one-tenth of it, the mobility becomes constant if the mesh becomes a quarter wavelength or smaller. We can conclude that dynamic parameters, such as eigenvalues, mode count, and mobility function, can be correctly estimated, while saving the computing burden, if a quarter wavelength (.lambda./4) mesh is used. Therefore, (.lambda./4) mesh is recommended in structural vibration analysis.

• 한국인터넷방송통신학회논문지
• /
• 제12권4호
• /
• pp.81-93
• /
• 2012

이동성관리 및 패킷전달에 의해 발생되는 전체 네트워크의 트래픽을 줄이기 위한 목적으로 PMIPv6(Proxy Mobile IPv6)에서 포인터전송을 기반으로 효율적인 이동성관리 기법을 제안한다. 제안기법은 개별적이며 동적인 모바일사용자 기반이다. 전체 네트워크의 트래픽을 최소화하기 위한 포워딩체인 길이의 최적 임계값과 사용자의 특정 이동성과 서비스 패턴을 기준으로 결정된다. 포워딩체인 길이의 최적 임계값이 존재하는 것을 주어진 특정 이동성과 모바일 사용자의 서비스 패턴을 특징화한 매개변수로 입증한다. 또한 제안기법이 모든 모바일 사용자에게 정적 임계값을 적용하는 방식보다 상당히 더 좋은 성능을 내는 것을 보여준다. 수학적 분석법은 포인터 포워딩 기법이 PMIPv6에서의 라우팅기반 이동성관리 프로토콜에 비해 뛰어난 성능을 보여준다.

• 한국IT서비스학회지
• /
• 제6권1호
• /
• pp.141-149
• /
• 2007

Sensor node's mobility brings new challenges to data dissemination in large sensor networks. Frequent location updates of sensor nodes can lead to both excessive drain of sensor's limited battery supply and increased collisions in wireless transmissions. Conventional studies for routing protocols in wireless sensor networks are not enough to cover energy consumption and migration of sensor nodes. This study proposes a dynamic routing protocol based on the SPIN considering energy consumption and the migration, and also shows the effectiveness of the proposed routing protocol.

• ETRI Journal
• /
• 제45권5호
• /
• pp.847-861
• /
• 2023

Dynamic object detection is essential for ensuring safe and reliable autonomous driving. Recently, light detection and ranging (LiDAR)-based object detection has been introduced and shown excellent performance on various benchmarks. Although LiDAR sensors have excellent accuracy in estimating distance, they lack texture or color information and have a lower resolution than conventional cameras. In addition, performance degradation occurs when a LiDAR-based object detection model is applied to different driving environments or when sensors from different LiDAR manufacturers are utilized owing to the domain gap phenomenon. To address these issues, a sensor-fusion-based object detection and classification method is proposed. The proposed method operates in real time, making it suitable for integration into autonomous vehicles. It performs well on our custom dataset and on publicly available datasets, demonstrating its effectiveness in real-world road environments. In addition, we will make available a novel three-dimensional moving object detection dataset called ETRI 3D MOD.

• Journal of Communications and Networks
• /
• 제15권5호
• /
• pp.504-513
• /
• 2013

Communication in delay tolerant networks (DTNs) relies on message transport by mobile nodes, and a correct understanding of the node mobility characteristics is therefore crucial to the design of an efficient DTN routing protocol. However, previous work has mainly focused on uncovering all behaviors of node movement, which is not conducive to accurately detecting the specific movement characteristics of a different node. In this paper, we seek to address this problem based on a consideration of social relationships. We first consider social ties from both static and dynamic perspectives. For a static perspective, in addition to certain accidental events, social relations are considered for a long time granularity and tend to be stable over time. For a dynamic perspective, social relations are analyzed in a relatively short time granularity and are likely to change over time. Based on these perspectives, we adopted different efficient approaches to dividing node pairs into two classes, i.e., familiar and unfamiliar pairs. A threshold approach is used for static social ties whereas a density-based aggregation method is used for dynamic social relationships. Extensive experimental results show that both familiar and unfamiliar node pairs have the same inter-contact time distribution, which closely follows a power-law decay up to a certain point, beyond which it begins to exponentially decay. The results also demonstrate that the inter-contact time distribution of familiar pairs decays faster than that of unfamiliar pairs, whether from a static or dynamic perspective. In addition, we also analyze the reason for the difference between the inter-contact time distributions of both unfamiliar and familiar pairs.

• 산업경영시스템학회지
• /
• 제38권4호
• /
• pp.11-21
• /
• 2015

In order to achieve success in ground operations, searching for moving targets is one of critical factors. Usually, the system of searching for adversary ground moving targets has complex properties which includes target's moving characteristics, camouflage level, terrain, weather, available search time window, distance between target and searcher, moving speed, target's tactics, etc. The purpose of this paper is to present a practical quantitative method for effectively searching for infiltrated moving targets considering aforementioned complex properties. Based upon search theories, this paper consists of two parts. One is infiltration route analysis, through terrain and mobility analysis. The other is building dynamic probability maps through Monte Carlo simulation to determine the prioritized searching area for moving targets. This study primarily considers ground moving targets' moving pattern. These move by foot and because terrain has a great effect on the target's movement, they generally travel along a constrained path. With the ideas based on the terrain's effect, this study deliberately performed terrain and mobility analysis and built a constrained path. In addition, dynamic probability maps taking terrain condition and a target's moving speed into consideration is proposed. This analysis is considerably distinct from other existing studies using supposed transition probability for searching moving targets. A case study is performed to validate the effectiveness and usefulness of our methodology. Also, this study suggests that the proposed approach can be used for searching for infiltrated ground moving target within critical time window. The proposed method could be used not only to assist a searcher's mission planning, but also to support the tactical commander's timely decision making ability and ensure the operations' success.

• 한국정보과학회:학술대회논문집
• /
• 한국정보과학회 2004년도 봄 학술발표논문집 Vol.31 No.1 (A)
• /
• pp.691-693
• /
• 2004

Mobile Ad hoc network은 stationary infrastructure의 도움 없이 이동 노드들이 필요 시 multi-hop wireless links network 형태를 구성하여 통신이 이루어지게 하는 network이다. 따라서 효율적인 라우팅 프로토콜의 개발이 중요한 issue인데 최근에는 routing overhead가 적은 on-demand 프로토콜이 주목을 받고 있다. On-demand 프로토콜은 새로운 route을 구성하기 위해서 query packet을 broadcasting하게 되는데, 특히 노드들의 mobility가 많은 mobile ad hoc network(MANET)의 경우에는 더욱더 자주 발생하게 되는데, blind broadcasting은 neighbor 노드들 간의 radio transmission region overlap에 의해 redundancy, contention, collision 같은 broadcast storm 문제를 발생시키게 된다. 본 논문은 on-demand 프로토콜의 broadcast storm 문제를 해결하기 위해 Neighbor Topology을 고려 한 Dynamic Adaptation Query flooding scheme을 제시한다. 또한 Dynamic Adaptive Query flooding scheme은 broadcast storm 문제 해결뿐만 아니라 network의 congestion을 감소시켜 data packet의 성능 향상에도 기여 할 것이다.

• 대한기계학회논문집
• /
• 제18권9호
• /
• pp.2339-2348
• /
• 1994

The objective of this paper is to develop a solution method for the differential-algebraic equation(DAE) derived from constrained muti-body dynamic systems. Mechanical systems are often modeled as bodies and joints. Differential equations of motion are formulated for bodies. Since the bodies are connected by joint, the differential variables must satisfy the kinematic constraint equations that come from the joints. Difficulties are arised due to drift of the differential variables off the constraint equations. An optimization method is adopted to correct the drift of the differential variables. To demonstrate the efficiency of the proposed method a slider-crank mechanism is analyzed dynamically. Identical results are obtained as these from the commercial program DADS. Dynamic analysis of a High Mobility Multi-purpose Wheeled. Vehicle(HMMWV) is carried out to show the practicalism of the proposed method.