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The rupture of an aneurysm can lead to a subarachnoid hemorrhage, which can be a fatal illness in a large percentage of cases. In treating aneurysm intravascular stenting is thought as a better option compared with clipping treatment. The treatment of cerebral aneurysm with a porous stent also has recently proposed as a minimally invasive way to prevent rupture and favor coagulation mechanism inside aneurysm. The analysis of a flow pattern with and without stent in cerebral aneurysm model was performed with Particle Image Velocimetry (PIV). Three types of stents were used in the present investigation and the porosity of stent 1, 2 and 3 is 80%, 74% and 64%, respectively. Reduced velocity, smaller average vorticity magnitude and different flow patterns inside aneurysm are observed when the three different proposed stents are used. The stent 3 (Porosity = 64%) decrease the magnitude of the velocity by 98% and change the flow pattern in the aneurysm. Our results show that not only the role of the porosity but also the stent shape affect the flow and help us understand the characteristic of stent designs.Copyright © 2011 by KSME

The growing interests in underwater wireless sensor networks(UWSNs) for a wide variety of purposes from Tsunami monitoring to commercial oilfield exploration projects have been encouraging. This paper deals with the problem of accurately tracking a single target moving through UWSNs employing acoustic sensors. This paper addresses the issues of estimating the target position, improving energy efficiency by applying a Kalman filter in a distributed architecture. Each underwater wireless sensor nodes composing the UWSNs is battery-powered, so the energy conservation problem is a critical issue. This paper provides an algorithm which increases energy efficiency of each sensor through a wake-up/sleep(WuS) and a valid measurement selecting(VMS) scheme. Simulation results illustrate the performance of the tracking filter according to the sensor node displacement and sensor detecting area.

Currently several kinds of sensor localization methods have been developed for terrestrial wireless sensor networks. In this paper, in order to extend the field to underwater environments, we study sensor localization technique for underwater wireless sensor networks(UWSNs). In underwater environments, radio frequency(RF) signal is not suitable for underwater usage because of extremely limited propagation. Because of that reason UWSNs should be constituted with acoustic modems. So we need a new localization algorithm to determine each sensors position. First of all we study the localization techniques for terrestrial environments where we investigate possible methods to underwater environment. And then we present the appropriate algorithm in the underwater usage. Finally we, evaluate the underwater based localization algorithm using computer based different conditions among communication range of sensor node, the nodes number and position of reference node.

In this paper, an overload detecting algorithm for an excavator is presented. The proposed overload detecting algorithm is based on the time series analysis especially moving window method and correlation function. The main purpose of this paper is to prevent damage or crack from the fatigue in advance. In this paper 16 channel sensor data are considered and each sensor frequency is 100 Hz and sampling period is lsec. So every sampling period 1600 data are gathered and computed, and the larger data, the longer process time. So this paper focuses on 2 topics. One is to short the process time. The other is to minimize the number of required sensors. To short the process time, this paper uses the moving window method. From the moving window method only data within each moving window are considered, so process time and process burden is shortened. And to minimize the number of required sensors, this paper uses the correlation function. From cross correlation function similar pattern sensors are eliminated and dissimilar pattern sensors are considered. And from using auto correlation function each dissimilar pattern sensor data are investigated to check overload or not. To prove the efficiency of the proposed overload detecting algorithm, this paper shows the computer simulation results.

We propose a rehabilitation training system for postural control using a tilting bed, a visual display and a force plate. Conventional rehabilitation systems for postural control have not been applicable to the patients who have to be lying in bed all the time. The rehabilitation training using those systems is only possible when the patient can stand up by himself or herself. Moreover, there did not exist any device that could provide the sense of balance or the sensation of walking to the patients in bed. The software for the system consists of the training part and the analysis part. The training part has been developed to provide various training scheme that help improve postural control ability of the subjects via repeated training of moving COP. The training consists of the COP maintaining training and the COP movement training in mediolateral, anterior-lateral, and posterior-lateral directions. The analysis part performs the assessments on the COP moving time, COP maintaining time, and mean absolute deviation before and after training for different tilt angles of the bed. Through the experiments ten subjects with the system, we tried to find the effectiveness of the advanced early rehabilitation training system. The results showed that this system is an effective system for early rehabilitation training and that our system can be used as clinical equipment.

In this paper, an overload detecting algorithm for an excavator is presented. The proposed overload detecting algorithm is based on the time series analysis especially moving window method and correlation function. The main purpose of this paper is to prevent damage or crack from the fatigue in advance. In this paper 16 channel sensor data are considered and each sensor frequency is 100 Hz and sampling period is 1 sec. So every sampling period 1600 data are gathered and computed, and the larger data, the longer process time. So this paper focuses on 2 topics. One is to short the process time. The other is to minimize the number of required sensors. To short the process time, this paper uses the moving window method. From the moving window method only data within each moving window are considered, so process time and process burden is shortened. And to minimize the number of required sensors, this paper uses the correlation function. From cross correlation function similar pattern sensors are eliminated and dissimilar pattern sensors are considered. And from using auto correlation function each dissimilar pattern sensor data are investigated to check overload or not. To prove the efficiency of the proposed overload detecting algorithm, this paper shows the computer simulation results.

Power-harvesting devices have received attention as power supplies for implantable medical devices. Power-harvesting technologies can overcome the limitation of a battery, such as limited battery lifetime and repeated surgical interventions. However, micropower generators do not meet the energy requirements of medical implants such as neural recording, implantable hearing aids, and implantable wireless sensors. They require an electrical power from 1 to 10 mW. This paper introduces an electromagnetic power generator using blood flow and blood pressure to drive an implanted medical device. The fabricated power generator, which is composed of a tiny rotor with magnets and external coils with ferrite cores, operates within a wide blood pressure range from 6.75 to 54.75 mmHg. In addition, the total volume and weight of the generator are 3.16 cc and 24 g, respectively. Using animal and mock-up tests, we verified the ability of the self-powered device to drive the medical implants. In the animal test, we utilized a blood pump to control the blood flow and blood pressure. The generator generated a maximum electrical power of 3.4 mW (conversion efficiency of 1.04%) at a blood pressure drop of 54.75 mmHg and blood flow of 2.68 L/min.

Risk assessments for toxicants in environmental media via oral exposure often rely on measurements of total concentration in a collected sample. However, the human digestive system cannot dissolute all of a toxicant present in the binding matrix, and cannot absorb it with nearly 100% efficiency. In vitro bioaccessibility has been developed as a method to estimate oral bioavailability of a toxicant using a physiologically-based extraction procedure. Bioaccessibility measurements are more physiologically relevant than strong acid leaching measurements of concentration. A method for measuring bioaccessible lead in house dust was derived from the bioaccessibility method currently used for heavy metals in contaminated soils. House dust was collected from carpets in typical urban residences. Bioaccessible lead was measured in house dust (

We propose a new training system using a tilting bed, a visual display and a force plate for an early rehabilitation. Conventional rehabilitation systems for postural control have not been applicable to the patients who have to be lying in bed all the time. The rehabilitation training using those systems is only possible when the patient can stand up by himself or herself. Moreover, there did not exist any device that could provide the sense of balance or the sensation of walking to the patients in bed. The software for the system consists of the training part and the analysis part. The training part has been developed to provide various training scheme that help improve postural control ability of the subjects via repeated training of moving COP. The training consists of the COP maintaining training and the COP movement training in mediolateral, anterior-lateral, and posterior-lateral directions. The analysis part performs the assessments on the COP moving time, COP maintaining time, and mean absolute deviation before and after the training for different tilt angles of the bed. Through the experiments on number of subjects with the system, we tried to find the effectiveness of the advanced early rehabilitation training system. The results showed that this system is an effective system for early rehabilitation training and that our system can be used as clinical equipment.

There developed a lower limb orthosis with a pneumatic rubber actuator, which can assist and improve the muscular activities in the lower limb of the elderly. For this purpose, the characteristics of the lower limbs muscle activities for various pressures in the pneumatic actuator for the lower limb orthosis was investigated. To find out the characteristics of the muscle activities for various pneumatic pressures, it analyzed the flexing and extending movement of the knees, and measured the lower limbs muscular power. The subjects wearing the lower limbs orthosis were instructed to perform flexing and extending movement of the knees. The variation in the air pressure of the pneumatic actuator was varies from one kgf/cm 2 to four kgf/cm 2 . The muscular power was measured by monitoring electromyogram using MP100 (BIOPAC Systems, Inc.) and detailed three-dimensional motions of the lower limbs were collected by APAS 3D Motion Analysis system. Through this study, it expected to find the most suitable air pressure for the improvement of the muscular power of the aged.

It proposed a new early rehabilitation training system for postural control using a tilting bed, a visual display and a force plate. The conventional rehabilitation systems for postural control can't be applied to the patients lying in bed because the rehabilitation training using those systems is only possible when the patient can stand up by himself or herself. Moreover, there did not exist any device that could provide the sense of balance or the sensation of walking to the patients in bed. The software for the system consists of the training program and the analysis program. The training program was designed to improve the ability of postural control of the subjects by repeated training of moving the center of pressure (COP) applied to the forceplate. The training program consists of the COP maintaining training and the COP movement training in horizontal, vertical, 45° and -45° directions. The analysis program consists of the COP moving time analysis modules, the COP maintaining time analysis module. Through the experiments with real people, it verified the effectiveness of the new early rehabilitation training system. The results showe that this system is an effective system for early rehabilitation training and that our system might be useful as clinical equipment.

The objective of the study was to investigate the effects of 3D stabilization exercises using a whole body tilt device on forces in the trunk, such as individual muscle forces and activation patterns, maximum muscle activities and spine loads. For this sake, a musculoskeletal (MS) model of the whole body was developed, and an inverse dynamics analysis was performed to predict the forces on the spine. An EMG measurement experiment was conducted to validate the muscle forces and activation patterns. The MS model was rotated and tilted in eight different directions: anterior (A), posterior (P), anterior right (AR), posterior right (PR), anterior left (AL), posterior left (PL), right (R) and left (L), replicating the directions of the 3D spine balance exercise device, as performed in the experiment. The anterior directions of the tilt primarily induced the activation of long and superficial back muscles and the posterior directions activated the front muscles. However, deep muscles, such as short muscles and multifidi, were activated in all directions of the tilt. The resultant joint forces in the right and left directions of the tilt were the least among the directions, but higher muscle activations and more diverse muscle recruitments than other positions were observed. Therefore, these directions of tilt may be suitable for the elderly and rehabilitation patients who require muscle strengthening with less spinal loads. In the present investigation, it was shown that 3D stabilization exercises could provide considerable muscle exercise effects with a minimum perturbation of structure. The results of this study can be used to provide safety guidelines for muscle exercises using this type of tilting device. Therefore, the proposed direction of tilt can be used to strengthen targeted muscles, depending on the patients' muscular condition.

Information on the work-time exposure of public bus and taxicab drivers to volatile organic compounds (VOCs) may be a critical factor in exploring the association between occupational exposure and health effects. Accordingly, this study evaluated the work-time VOC exposure of public bus and taxicab drivers by measurement of six selected aromatic VOC concentrations in the personal air of public bus and taxicab drivers during winter and summer. Two groups of five public bus drivers (smokers and nonsmokers) and two groups of five taxicab drivers (smokers and nonsmokers) were recruited for the study. The taxicab drivers were found to be exposed to higher aromatic compound levels than the bus drivers during their daily work time. The personal exposure of the bus and taxicab drivers was influenced by whether or not they smoked plus the season. It was also established that the potential exposure of bus drivers to aromatic VOCs did not exceed that of an unemployed reference group, whereas the potential exposure of taxicab drivers did. Meanwhile, based on comparison of the calculated in-vehicle concentrations with those from a previous study, the VOC levels inside public buses and taxicabs were found to be lower than those inside automobiles.

In this study, a new cycle ergometer system using a magneto-rheological (MR) rotary brake was developed to improve muscular strength and reduce asymmetric pedaling characteristics for the rehabilitation of hemiplegia patients. For evaluation of this cycle ergometer, the characteristics of lower limb muscles were analyzed according to three factor of cycle system with MR rotary brake: (1) the electrical current of MR rotary brake, (2) the intensity and duration of cycling, (3) the application of visual feedback. The results showed that muscle activity was significantly different for various levels of current applied to the MR rotary brake. A higher current was associated with a higher integrated electromyography (IEMG) of the lower limb muscle. In low-intensity and long-term condition, IEMG of RF, TA, VL and VAS increased in the late stage of exercise (compared to the early stage), however, decreased in high-intensity and short term condition. The asymmetry of pedaling between the dominant and non-dominant leg was 19.63% in the non-visual feedback mode and 1.97% in the visual feedback mode. Therefore, our new cycle system using an MR brake with real time control of mechanical resistance can be used to enhance muscle strength in patients with hemiplegia and elderly people. Increased muscular activity of the lower limbs in patients with hemiplegia and the elderly is expected with low-intensity training over a long-term period.

A short time reflow of 15s at 250°C, followed by a liquid nitrogen quench, of the Sn–3Ag–0.5Cu solder on a Cu substrate gave rise to a three-layer interfacial structure. In addition to the commonly known η-Cu6Sn5∕e-Cu3Sn layers, an amorphous layer with a thickness of less than 50nm exists between the Cu substrate and the thin e-Cu3Sn layer. Nanocrystalline e-Cu3Sn cells, revealed by transmission electron microscopy (TEM), as fine as 10nm were detected within the amorphous region. The results of TEM analysis suggest that the nucleation of interfacial intermetallic compound e-Cu3Sn occurs within the amorphous layer.