• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.2
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• pp.137-144
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• 2015

In this paper, we present an inertial sensor-based gait analysis system to measure and analyze lower-limb movements. We developed an integral AHRS(Attitude Heading Reference System) using a combination of rate gyroscope, accelerometer and magnetometer sensor signals. Several AHRS modules mounted on segments of the patient's body provide the quaternions representing the patient segments's orientation in space. And a method is also proposed for calculating three-dimensional inter-segment joint angle which is an important bio-mechanical measure for a variety of applications related to rehabilitation. To evaluate the performance of our AHRS module, the Vicon motion capture system, which offers millimeter resolution of 3D spatial displacements and orientations, is used as a reference. The evaluation resulted in a RMSE(Root Mean Square Error) of 1.08 and 1.72 degree in yaw and pitch angle. In order to evaluate the performance of our the gait analysis system, we compared the joint angle for the hip, knee and ankle with those provided by Vicon system. The result shows that our system will provide an in-depth insight into the effectiveness, appropriate level of care, and feedback of the rehabilitation process by performing real-time limb or gait analysis during the post-stroke recovery.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.703-714
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• 2011

The purpose of this study was to investigate the effect of STS modules reflecting Ansan's geological characteristics in Chemistry I on high school students' science related attitudes and preference for STS lessons. The subjects were 10th grade students from K High School in Ansan and comprised 71 students in the experiment group and 78 students in the control group from 2 classes each. Pretest-posttest control group design was employed for the purpose of research. Four STS modules with lesson plans and teaching materials with themes of water, air, and energy, all of which are closely related to high school Chemistry I were developed and applied to the experiment group. The science related attitudes and preference for STS lessons were then examined in pre- and post-tests. The science related attitudes of the experiment group were significantly high in three out of five domains compared to the control group who was taught traditionally. The preference for STS lessons of the experiment group were highly positive in all five areas and were particularly high in the area of 'relation to society'. Such results imply that in order to make effective high school Chemistry I curriculum units related to STS, emphasized by both the 7th National Curriculum and the Revised 7th National Curriculum, it is necessary to use episodes reflecting local characteristics in which students show greater interest and active participation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.152-164
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• 2015

A rapid development of semiconductors, sensors and mobile network technologies has enable that the embedded device includes high sensitivity sensors, wireless communication modules and a video processing module for vehicular environment, and many researchers have been actively studying the smart car technology combined on the high performance embedded devices. The vehicle is increased as the development of society, and the risk of accidents is increasing gradually. Thus, the advanced driver assistance system providing the vehicular status and the surrounding environment of the vehicle to the driver using various sensor data is actively studied. In this paper, we design and implement the smart vehicular camera device providing the V2X communication and gathering environment information. And we studied the method to create the metadata from a received video data and sensor data using video analysis algorithm. In addition, we invent S-ROI, D-ROI methods that set a region of interest in a video frame to improve calculation performance. We performed the performance evaluation for two ROI methods. As the result, we confirmed the video processing speed that S-ROI is 3.0 times and D-ROI is 4.8 times better than a full frame analysis.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.6
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• pp.323-328
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• 2016

Pressurized membrane used for side-stream MBR process requires fouling control strategy both for normal and abnormal operation conditions for stable operation of the facilities. In this study, $85m^3/day$ of pilot-scale side-stream MBR process was constructed for the evaluation of fouling mitigation by air bubble injection into the membrane module. In addition, fouling phenomena at abnormal operation conditions of low influent and/or loading rate were also investigated. Injection of air bubble was found to be effective in delaying transmembrane pressure (TMP) increase mainly due to scouring effect on the membrane surface, resulting in expanded filtration cycle at a high flux of $40L/m^2{\cdot}h$ (LMH). At abnormal operation condition, injection of PACl (53 mg/L as Al) into the bioreactor showed 19% reduction of TMP increase. However, inhibition of nitrifying bacteria by continuous PACl injection was observed from batch experiments. In contrast, injection of powdered activated carbon (PAC, 0.6 g/L) was able to maintain the initial TMP of $0.2kg/cm^2$ for 5 days at the abnormal conditions. It may have been caused from the adsorption of extracellular polymeric substances (EPS), which was known to be excessively released during growth inhibition condition and act as the major foulants in MBR operations.

• Korean Journal of Applied Biomechanics
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• v.20 no.4
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• pp.469-477
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• 2010

The purpose of this study was to evaluate the effects of insole-equipped ankle-foot-orthoses (AFO) on gait. 10 healthy males who had no history of injury in the lower extremity participated in this study as the subjects. The foot of each subject was first scanned, and the insole fit to the plantar was made using BDI-PCO(Pedcad Gmbh, Germany). The subject then was made to walk on a treadmill under four experimental conditions: 1) normal walking, 2) walking wearing AFO, 3) walking wearing AFO equipped with the insole, 4) walking wearing pneumatic-ankle-foot-orthosis (pAFO) equipped with the insole. During walking, foot pressure data such as maximum force, contacting area, peak pressure, and mean pressure was collected using Pedar-X system (Novel Gmbh, Germany) and EMG activity of lower limb muscles such as gastrocnemius medial head, gastrocnemius lateral head, and soleus was recorded using MP150 EMG module (BIOPAC System Inc., USA). Collected data was then analyzed using paired t-test in order to investigate the effects of the insole. As a result of the analysis, when insole was equipped, overall contacting area was increased while both the highest peak pressure and the mean pressure were significantly decreased, and EMG activity of the lower limb muscles was decreased. On the contrary, the cases of wearing AFO showed the decreased contacting area and the increased pressures. Therefore, the AFO equipped with a proper insole fit well to the foot can help comfortable walking by spreading the pressure over the entire plantar.

• Journal of Korean Society of Transportation
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• v.22 no.6
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• pp.77-88
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• 2004

This study aims at developing the model that is able to detect the compression wave, which is included as a similar situation in incidents, that causes false applicable to the similar character such as incidents in the incident detection model for expressways. In this study, it has been checked whether the number of false alarms is decreased or not by modularizing this model for being able to applicable to other models such as DES and DELOS, etc. which do not perform the compression wave test based on the compression wave test process of APID model which has been being used in the expressway traffic management system currently. The evaluation in this study focuses on the sensitivity of the model and the results analysis is performed classified by each polling cycle. And how well these models are working is evaluated by each polling cycle. In addition to this, the detection rate, the false alarm rate and the average detection time in both the existing models and the model in this study are calcuated. As a result of appling the model in this study, it is found that the false alarm rate is improved through the reasonable decrease in the number of false alarm frequencies and there are not remarkable changes concerning the detection rate and the average detection time. To sum up, it is expected that a good number of improvement effects will be occurred when this model is applied to the actual expressway traffic management system.

• Journal of Internet Computing and Services
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• v.13 no.4
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• pp.83-93
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• 2012

HTML5 has developed not to have browser dependancy considering interoperability as same as maintaining compatability with lower versions of HTML. HTML5, the newest web standardization is on going of being structured. Along with the smart phone boom, HTML5 is spotlighted because it can be applied to cross platforms in mobile web environments. Specially the local Storage that has been listed in new features in HTML5 supports offline function for web application that enables web application to be run even when the mobile is not connected to 3G or wifi. With Local storage, development of server-independent web application can be possible. However Local storage stores plaintext data in it without applying any security measure and this makes the plaintext data dangerous to security threats that are already exist in other client side storages like Cookie. In the paper we propose secure Local storage methods to offer a safe way to store and retrieve data in Local storage guaranteeing its performance. Suggested functions in this paper follow localStorage standard API and use a module that provide cryptographic function. We also prove the efficiency of suggested secure Local storage based on its performance evaluation with implementation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3628-3633
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• 2012

This paper proposes a model of the real time monitoring system based on Ubiquitous Sensor Network (USN) for the detection and prediction of landslides. For this purpose, the real time monitoring system with tilting sensor and USN was set up and the performance was conducted. The performance was accomplished by conducting both field examinations and the experimental evaluation of the monitoring system. The results of this study show that the angle $0^{\circ}$, $-10^{\circ}$, $-20^{\circ}$ and $0{\sim}-30^{\circ}$ of sensor position detected by the sensor module coincide with the data measured from USN monitoring system by giving a sampling time 100[msec]. Consequently, the proposed model of the real time monitoring system with tilting sensor based on USN will be widely used as a monitoring system in the exposure to dangerous landslide regions.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.11
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• pp.836-840
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• 2009

Many researchers have studied flash memory in order to replace hard disk storages. Many FTL algorithms have been proposed to overcome physical constraints of flash memory such as erase-before-write, wear leveling, and poor write performance. Therefore, these constraints should be considered for testing FTL algorithms and the performance evaluation of flash memory. As doing the experiments, we suffer from several problems with costs and settings in experimental configuration. When we, for example, replay the traces of Oracle to evaluate the I/O performance with flash memory, it is hard to extract exact traces of I/O operations in Oracle. Since there are only write operations in the log, it is impossible to gather read operations. In MySQL and SQLite, we can gather the read operations by changing I/O functions in the source codes. But it is not easy to search for the exact points about I/O and even if we can find out the points, we might get wrong results depending on how we modify source codes to get I/O traces. The FlaSim proposed in this paper removes the difficulties when we evaluate the performance of FTL algorithms and flash memory. Our Linux drivers emulate the flash memory as a hard disk. And we can easily obtain the usage statistics of flash memory such as the number of write, read, and erase operations. The FlaSim can be gracefully extended to support the additional modules implemented by novel algorithms and ideas. In this paper, we describe the structure of FTL emulator, development tools and operating methods. We expect this emulator to be helpful for many experiments and research with flash memory.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.647-654
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• 2016

In the defense industry, national security takes priority over economic sense and this has translated into high cost and long-term research and development. However, the exponential growth of technology and rapid changes in the security situation in recent years have resulted in a call for the development of systems at a low cost within a short period of time. In order to implement a modularization strategy in the field of defense, the introduction of line replaceable units in OO systems needs to be prioritized. This study selects six criteria following a literature review and prioritizes 11 modules for OO systems using the project evaluation method, Grey Relational Analysis (GRA). Based on the GRA results, the grey relational grades were derived as 0.83, 0.81 and 0.80 for the M11 (Main board), M8 (EMI module), M3 (Single board computer) modules, respectively. The cost and time of development is expected to be reduced in accordance with the grey relational grade. The results of this research could be utilized for decision making on adopting modularization in similar system development or product improvement programs (PIPs).