• The Journal of Korean Physical Therapy
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• v.1 no.1
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• pp.15-25
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• 1989

The purpose of this study was to determine the factors influencing the standing balance of independent ambulatory hemiparetic patients. The subjects of this study were 30 hemiparetic patients (18 males, 12 females) being treated as admitted or out patients at Severance Hospital Medical Center, all of whom agreed to participate in the study. In order to assure the statistical significance of the results, the paired t-test aid a Pearson's correlation were applied at the .05 level of significance. The results were as follows. 1. The difference in maintenance time of standing balance on a stable and unstable support surface was significant at the .05 level. 2. The difference in maintenance time of standing balance according to the control of visual and acoustic stimuli was significant at the .05 level. 3. The presence or absence of passive joint motion sense influenced the standing balance maintenance time. 4. There was no significant difference in the maintenance standing balance of the sound tower leg standing conditions according to spasticity, but the paretic lower leg standing conditions were significantly different (p<.05). This type of evaluation should be more widely used in the field of evaluating standing balance with hemiparetic patients. However, more extensive study and reports on various factors of standing balance are needed.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.6
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• pp.547-553
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• 2006

This paper studies digital control of biodynamic model of HIV-1 via intelligent digital redesign (IDR). The purpose of the IDR is to develop an equivalent digital fuzzy controller maintaining the satisfactory performance of an existing continuous-time fuzzy controller in the sense of the state-matching. Some conditions for the stability as well as the global state-matching are provided.. They are given by the form of the linear matrix inequalities (LMIs) and thereby easily tractable by the convex optimization techniques. The main features of the proposed method are that 1) the generalized control scheme is provided for the multirate as well as the single-rate digital controllers; 2) a new compensated block-pulse function method is applied to closely match the states of the continuous-time and the sampled-data fuzzy systems in the discrete-time domain; 3) the two-step procedure of IDR is presented to prevent the performance degradation caused by the additional stability conditions. The applicability of the proposed approach is shown through the biodynamic model of HIV-1.

• 한국정보컨버전스학회:학술대회논문집
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• 2008.06a
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• pp.199-204
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• 2008

Sensor nodes have various energy and computational constraints because of their inexpensive nature and ad-hoc method of deployment. Considerable research has been focused at overcoming these deficiencies through faster media accessing, more energy efficient routing, localization algorithms and system design. Our research attempts to provide a method of improvement MAC performance in these issues. We show that traditional carrier-sense multiple access(CSMA) protocols like IEEE 802.11 do not handle the first constraint adequately, and do not take advantage of the second property, leading to degraded latency and throughput as the network scales in size, We present more efficient method of a medium access for real-time wireless sensor networks. Proposed MAC protocol is a randomized CSMA protocol, but unlike previous legacy protocols, does not use a time-varying contention window from which a node randomly picks a transmission slot. To reduce the latency for the delivery of event reports, it carefully decides a fixed-size contention window, non-uniform probability distribution of transmitting in each slot within the window. We show that it can offer up to several times latency reduction compared to legacy of IEEE 802.11 as the size of the sensor network scales up to 256 nodes using widely used simulator ns-2. We, finally show that proposed MAC scheme comes close to meeting bounds on the best latency achievable by a decentralized CSMA-based MAC protocol for real-time wireless sensor networks which is sensitive to latency.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.160-163
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• 1993

In this paper, design of an automatic grinding robot system for car brazing bead is introduced. Car roof and side panels are joined using brazing, and then the brazing bead is processed so that the bead is invisible after painting. Up to now the grinding process is accomplished manually. The difficulties in automation of the grinding process are induced by variation of position and shape of the bead and non-uniformity of the grinding area due to surface deformation. For each car, the grinding area including the brazing bead is sensed and then modeled using a 2-D optical sensor system. Using these model data, the position and the direction of discrete points on the car, body surface are obtained to produce grinding path for a 6 degrees of freedom grinding robot. During the process, it is necessary to sense the reaction forces continuously to prepare for the unexpected circumstances. In addition, to meet the line cycle time it is necessary to reduce the required time in sensing, signal processing, modeling, path planning and data transfer by utilizing real-time communication of the information. The key technique in the communication and integration of the complex information is obtaining in-field reliability. This automatic grinding robot system may be regarded as a jump in the intelligent robot processing technique.

• Journal of Distribution Science
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• v.21 no.7
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• pp.73-82
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• 2023

Purpose: Social networking services have been recognized as an attractive distribution channel at a time when efforts to deliver effective messages to consumers are essential amid a flood of advertisements in the multi-media era. In that sense, this study investigated the effect of the scarcity message type (limited-time vs. limited-quantity) and sender type (corporate vs. consumer) on the intention to purchase golf equipment by Instagram distribution channel. Research design, data and methodology: Data from 108 college students in their 20s and 30s with experience using Instagram were collected online through convenience sampling. A frequency analysis, exploratory factor analysis, reliability analysis, independent sample t-test, and two-way analysis of variance were performed using SPSS 23.0. Results: The results showed that limited-quantity messages induce a higher purchase intention than limited-time messages. Similarly, consumer-sent advertisements induce a higher purchase intention than corporate-sent advertisements. Further, there is no statistically significant interaction effect of the scarcity message type and sender type on the intention to purchase golf equipment. Conclusions: This study is meaningful in verifying consumers' purchase intention depending on the type of scarcity message and the type of sender in Instagram advertisements. The results yield significant implications for marketers and several directions for future research.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.1
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• pp.1-7
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• 2015

In this paper, a 12-bit high resolution, power and area efficiency hybrid digital pulse width modulator (DPWM) with process and temperature (PT) calibration has been proposed for digital controlled DC-DC converters. The hybrid structure of DPWM combines a 6-bit differential tapped delay line ring-mux digital-to-time converter (DTC) schema and a 6-bit counter-comparator DTC schema, resulting in a power and area saving solution. Furthermore, since the 6-bit differential delay line ring oscillator serves as the clock to the high 6-bit counter-comparator DTC, a high frequency clock is eliminated, and the power is significantly saved. In order to have a simple delay cell and flexible delay time controllability, a voltage controlled inverter is adopted to build the deferential delay cell, which allows fine-tuning of the delay time. The PT calibration circuit is composed of process and temperature monitors, two 2-bit flash ADCs and a lookup table. The monitor circuits sense the PT (Process and Temperature) variations, and the flash ADC converts the data into a digital code. The complete circuits design has been verified under different corners of CMOS 0.18um process technology node.

• Korean Journal of Human Ecology
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• v.17 no.3
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• pp.399-411
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• 2008

The study purposes to survey teacher's and child's difficulties which full day classes of public kindergarten regrouped in the afternoon time are having. The subjects are 4 full day class pre-service kindergarten teachers and 8 full-day class children in G Metropolitan City and in J Province. Data were collected through in depth interviews and participatory observation. According to the results, the variables of teachers' difficulties in managing full day classes regrouped in the afternoon time are "living as an outsider without a sense of belonging", "living as a false teacher rather than a real class teacher", and "living as a teacher giving specialty and aptitude education". The variables of children's difficulties are "moving like a migratory bird", "watching the clock and the door", and "being unable to concentrate". The study is expected to be useful as one of basic findings for desirable management of kindergarten full day classes regrouped in the afternoon time.

• Journal of the Korea Safety Management & Science
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• v.19 no.1
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• pp.181-189
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• 2017

The systematic management of technology infrastructure increasingly becomes critical as it represents the driving power for creating competitive advantage of nations and enterprises. In this sense, public facility and equipment, which is one major asset of technology infrastructure, should be managed effectively, systematically and efficiently to increase its overall equipment effectiveness. However, the manual and off-line communication was the unique way to communicate between the suppliers who provide facilities in the public sector and the customers who utilize the facilities in the industrial sector. This communication way caused invisibility of available usage time and increase of idle time, thereby decreasing the equipment effectiveness. This paper presents an web-based scheduling system that enables real-time collaboration and information sharing for increasing the equipment effectiveness. The designed system performs scheduling, facility management, order management and customer relationship management in an on-line platform, and carries out the processing and storing of relevant information in an integrated database. The paper includes a development approach to identify business process models and standardized system models by using object-modeling technique. The deliverable of the present work will contribute to increasing the equipment effectiveness by enhancing visibility, transparency and predictability by means of the integration with a legacy Enterprise Resource Planning.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.4
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• pp.213-219
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• 2015

Real-time energy monitoring systems is a demand-response system which is reported to be effective in saving energy up to 12%. Real-time energy monitoring system is commonly composed of smart-plugs which sense how much electrical power is consumed and IHD(In-Home Display device) which displays power consumption patterns. Even though the monitoring system is effective, users should themselves match which smart plus is connected to which appliance. In order to make the matching work to be automatic, the monitoring system need to have appliance identification algorithm, and some works have made under the name of NILM(Non-Intrusive Load Monitoring). This paper proposed an algorithm which utilizes multiple classifiers to improve accuracy of appliance identification. The algorithm proposes to understand each classifiers performance, that is, when a classifier make a result how much the result is reliable, and utilize it in choosing the final result among result candidates from many classifiers. By using the proposed algorithm this paper make 4.5% of improved accuracy with respect to using single best classifier, and 2.9% of improved accuracy with respect to other method using multiple classifiers, so called CDM(Commitee Decision Mechanism) method.

• Journal of Korea Game Society
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• v.17 no.4
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• pp.55-62
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• 2017

In this study, motion simulation of Walk-through was evaluated with HMD(Head Mounted Display). More Specifically, we examined the changes of the degree of object density placed around virtual space on psychological moving distance, moving speed, and moving time. The results were as follows. First, the difference between the experimental conditions(low density, Medium density, High density) was significant. Second, as the density of the surrounding objects increased, the average point of moving time, moving speed, and moving distance rose compared to the basic conditions. Third, it was found that the surrounding objects improved the sense of time, speed and distance in motion simulation in virtual space.