• Journal of Institute of Control, Robotics and Systems
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• v.18 no.4
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• pp.353-358
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• 2012

Human detection is a challenging task in many fields because it is difficult to detect humans due to their variable appearance and posture. Furthermore, it is also hard to track the detected human because of their dynamic and unpredictable behavior. The evaluation speed of method is also important as well as its accuracy. In this paper, we propose unified detection and tracking method for humans using Gaussian-PSO (Gaussian Particle Swarm Optimization) with the HOG (Histograms of Oriented Gradients) features to achieve a fast and accurate performance. Keeping the robustness of HOG features on human detection, we raise the process speed in detection and tracking so that it can be used for real-time applications. These advantages are given by a simple process which needs just one linear-SVM classifier with HOG features and Gaussian-PSO procedure for the both of detection and tracking.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.4
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• pp.350-356
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• 2004

This paper presents a farce manipulability analysis of multi-legged walking robots, which calculates force or acceleration workspace attainable from joint torque limits of each leg. Based on the observation that the kinematic structure of the multi-legged walking robots is basically the same as that of multiple cooperating robots, we derive the proposed method of analyzing the force manipulability of walking robot. The force acting on the object in multiple cooperating robot systems is taken as reaction force from ground to each robot foot in multi-legged walking robots, which is converted to the force of the body of walking robot by the nature of the reaction force. Note that each joint torque in multiple cooperating robot systems is transformed to the workspace of force or acceleration of the object manipulated by the robots in task space through the Jacobian matrix and grasp matrix. Assuming the torque limits are given in infinite norm-sense, the resultant dynamic manipulability is derived as a polytope. The validity of proposed method is verified by several examples, and the proposed method is believed to be useful for the optimal posture planning and gait planning of walking robots.

• Asia pacific journal of information systems
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• v.12 no.3
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• pp.135-167
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• 2002

This research focuses on the IS development methodology as an object of innovation in an IS organization. It has two main research objectives. It was intended to understand the critical affecting factors which have an effect on the processing of each level in the dynamic and evolving innovation process. There are two levels of innovation process: initiation and implementation. It was also intended to understand the performance of IS organizational innovation. We found three main results by the LISREL analysis. First, main factors affecting initiation level of innovation are innovative tendency of IS members, communication level of IS organization, existence of champion manager, IS performance gap, executive supporting to IS, and relative advantage of IS development methodology. At the implementation level, it was understood that the existence of champion manager, executive support, and relative advantage of IS development methodology were the main factors promoting to use the innovation, and the complexity of innovation was a negative factor adopting the usage of innovation. Second, the quality of the previous level in the gradual innovation activities gives very notable affection to the continuous next level. Finally, it was found that the qualitative performance like the documentation, collaborative team approach, IS developer's awareness and ability corresponding to their task and so on was improved due to the IS organizational innovation. This research provides the standard framework for the IS organizational innovation in a structural way. In the practical aspect, it may be used as the principle for introducing and using the IS development methodology.

• Structural Monitoring and Maintenance
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• v.3 no.3
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• pp.195-214
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• 2016

Monitoring of impact loads is a very important technique in the field of structural health monitoring (SHM). However, in most cases it is not possible to measure impact events directly, so they need to be reconstructed. Impact load reconstruction refers to the problem of estimating an input to a dynamic system when the system output and the impulse response function are usually known. Generally this leads to a so called ill-posed inverse problem. It is reasonable to use prior knowledge of the force in order to develop more suitable reconstruction strategies and to increase accuracy. An impact event is characterized by a short time duration and a spatial concentration. Moreover the force time history of an impact has a specific shape, which also can be taken into account. In this contribution these properties of the external force are employed to create a sample-force-dictionary and thus to transform the ill-posed problem into a sparse recovery task. The sparse solution is acquired by solving a minimization problem known as basis pursuit denoising (BPDN). The reconstruction approach shown here is capable to estimate simultaneously the magnitude of the impact and the impact location, with a minimum number of accelerometers. The possibility of reconstructing the impact based on a noisy output signal is first demonstrated with simulated measurements of a simple beam structure. Then an experimental investigation of a real beam is performed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.7
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• pp.3018-3040
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• 2018

The mobility model is one of the most important factors that impacts the evaluation of any transportation vehicular networking protocols via simulations. However, to obtain a realistic mobility model in the dynamic urban environment is a very challenging task. Several studies extract mobility models from large-scale real data sets (mostly taxi GPS data) in recent years, but they do not consider the statuses of taxi, which is an important factor affected taxi's mobility. In this paper, we discover three simple observations related to the taxi statuses via mining of real taxi trajectories: (1) the behavior of taxi will be influenced by the statuses, (2) the macroscopic movement is related with different geographic features in corresponding status, and (3) the taxi load/drop events are varied with time period. Based on these three observations, a novel taxi mobility model (T-START) is proposed with respect to taxi statuses, geographic region and time period. The simulation results illustrate that proposed mobility model has a good approximation with reality in trajectory samples and distribution of nodes in four typical time periods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.7
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• pp.2977-2997
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• 2018

In big data era, fresh data grows rapidly every day. More than 30,000 gigabytes of data are created every second and the rate is accelerating. Many organizations rely heavily on real time streaming, while big data stream computing helps them spot opportunities and risks from real time big data. Storm, one of the most common online stream computing platforms, has been used for big data stream computing, with response time ranging from milliseconds to sub-seconds. The performance of Storm plays a crucial role in different application scenarios, however, few studies were conducted to evaluate the performance of Storm. In this paper, we investigate the performance of Storm under different application scenarios. Our experimental results show that throughput and latency of Storm are greatly affected by the number of instances of each vertex in task topology, and the number of available resources in data center. The fault-tolerant mechanism of Storm works well in most big data stream computing environments. As a result, it is suggested that a dynamic topology, an elastic scheduling framework, and a memory based fault-tolerant mechanism are necessary for providing high throughput and low latency services on Storm platform.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.607-612
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• 2004

Disc brake noise continues to be a major concern throughout the automotive industry despite efforts to reduce its occurrence. Eliminating vibrations during braking is an important task for both vehicle passenger comfort and reducing the overall environmental noise levels. There are several classes of disc brake noise, the major ones being squeal, judder, groan, and moan. In this study, analytical model for moan noise of rear disk brake is investigated. Modeling of the disc brake assembly to take account of the effect of different geometrical and contact parameters is studied through the use of multi-body model. The contact stiffness of the caliper and torque member plays an important role in controlling brake vibration. Therefore, a suitable material pair at the caliper/body contact has been made. An ADAMS model of a rear disc brake system was integrated with a flexible suspension trailng arm from MSC/NASTRAN. A fully non-linear dynamic simulatin of brake system behavior, containing rigid and flexible bodies, was performed for a Prescribed set of operating conditions. Simulation results were validated using data from vehicle experimental testing.

• Korean Journal of Applied Biomechanics
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• v.28 no.3
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• pp.193-197
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• 2018

Objective: The relationship between the rest intervals during physical tasks and performance enhancement has been studied. However, whether or not different rest intervals would result in altered multiplanar ankle kinematics during performance of the Star Excursion Balance Test (SEBT) is unknown. Method: Fifteen healthy subjects (7 males and 8 females) without a history of ankle injuries were participated in this study. 3 rest intervals of 10, 20, and 40 seconds were used during the current study. Three visits were required in order to complete the 3 rest intervals. Variables of interest included dorsiflexion (DF) excursion, tibial internal rotation (TIR), and eversion (EV) excursions. The means of ankle angular excursions were compared across the 3 directions in the 3 rest interval groups. Results: There were no significant main effects for any variables between restintervals. However, DF excursion in the anteromedial (AM) direction was greaterthan in both the medial (M) and posteromedial (PM) directions and was greater in the M direction compared to the PM direction. TIR excursion in the AM direction was less than in both the M and PM directions. Conclusion: Different rest intervals ranging from 10 to 40 seconds did not influence ankle angular excursions during the SEBT in a healthy population. However, our results suggest that multiplanar motion is necessary during the SEBT and differs depending on the direction of movement.

• Korean Journal of English Language and Linguistics
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• v.3 no.3
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• pp.453-497
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• 2003

The purpose of this study is to investigate social aspects of young EFL learners' interaction at the computer. Data were taken from the interactions of three pairs of fourth-grade primary school children who worked together on English learning software. Their interactions at the computer were videotaped and then all the talk produced by the students and the utterances emitted from the computer were transcribed. As for the analytical tools, the notion of ‘contextualization cues’ (Gumperz, 1982) and the concept of ‘positioning’ (Davies & Harre,1990) were employed. The analysis reveals that the roles of the students were not tied to a certain position, but rather dynamically changed during the course of interactive work according to the situation at hand. The dynamic changes in their positions were realized through various means; their capability in solving problems, their taking responsibility or assigning it to each other, or cooperation. There were also instances of peer teaching and motivated learning. In addition, the students showed autonomy in their learning activity. These findings suggest that both students in a dyad had their own place in performing task activities, contributing to solving problems and getting benefits from peer interaction. Furthermore, students' working together on English learning software may provide an environment which can promote cooperative attitude and responsibility for learning and enhance motivation and autonomy in their learning process.

• Computers and Concrete
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• v.21 no.4
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• pp.441-449
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• 2018

FE models for complex or large-scaled structures that need detailed modeling of structural components are usually constructed using commercial analysis softwares. Updating of such FE model by conventional sensitivity-based methods is difficult since repeated computation for perturbed parameters and manual calculations are needed to obtain sensitivity matrix in each iteration. In this study, an FE model updating procedure avoiding such difficulties by using response surface (RS) method and a Pareto-based multiobjective optimization (MOO) was formulated and applied to FE models constructed with a commercial analysis package. The test building is a low-rise reinforced concrete building that has been seismically retrofitted. Dynamic properties of the building were extracted from vibration tests performed before and after the seismic retrofits, respectively. The elastic modulus of concrete and masonry, and spring constants for the expansion joint were updated. Two RS functions representing the errors in the natural frequencies and mode shape, respectively, were obtained and used as the objective functions for MOO. Among the Pareto solutions, the best compromise solution was determined using the TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) procedure. A similar task was performed for retrofitted building by taking the updating parameters as the stiffness of modified or added members. Obtained parameters of the existing building were reasonably comparable with the current code provisions. However, the stiffness of added concrete shear walls and steel section jacketed members were considerably lower than expectation. Such low values are seemingly because the bond between new and existing concrete was not as good as the monolithically casted members, even though they were connected by the anchoring bars.