• The Journal of Information Systems
• /
• v.29 no.4
• /
• pp.153-169
• /
• 2020

Purpose Many students have concerned about the quality and operation of online courses with universities offering online courses to avoid the spread of COVID-19. To deepen our understanding of university online class systems, this research aims to assess students' satisfaction with online class systems and continuous usage intention on the basis of the perceived benefits and expectation confirmation theory. Design/methodology/approach This paper empirically analyzes the impact of each perceived benefit on user satisfaction and the intention to use it continuously by dividing the perceived benefits considered in existing literature into utilitarian benefits (convenience), emotional benefits (pleasure), and symbolic benefits (personal benefits). Moreover, the perceived expectations and performance have also been assessed with its impact on satisfaction and the intention to continue use. Data collected from 241 university students were empirically tested against a research model. Findings Analysis results showed that perceived advantages (comfort, enjoyment and personalized benefit) significantly affect user satisfaction and that perceived benefits have positive effects on the intention to continue use whereas the expected confirmation do not significantly influence on the intention to continue use.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.46 no.1
• /
• pp.70-81
• /
• 2010

A mathematical model is formulated to study the effect of wall mass on the thermal performance of four different houses of different construction. This analytical study was motivated by the experimental work of Burch et al. An analytical solution of one -dimensional, linear, partial differential equation for wall temperature profiles and room air temperatures is obtained using the Laplace transform method. Typical Meteorological Year data are processed to yield hourly average monthly values. These discrete data are then converted to a continuous, time dependent form using a Fast Fourier Transform method. This study is conducted using weather data from four different locations in the United States: Albuquerque, New mexico; Miami, Florida; Santa Maria, California; and Washington D.C. for both winter and summer conditions. A computer code is developed to calculate the wall temperature profile, room air temperature, and energy consumption loads. Three sets of results are calculated one for no auxiliary energy and two for different control mechanism -- an on-off controller and a proportional controller. Comparisons are made for the cases of two controllers. Heavy weight houses with insulation in mild weather areas (such as August in Santa Maria, California) show a high comfort level. Houses using proportional control experience a higher comfort level in comparison to houses using on-off control. The result shows that there is an effect of mass on the thermal performance of a heavily constructed house in mild weather conditions.

• The Korean Journal of Pain
• /
• v.7 no.2
• /
• pp.199-204
• /
• 1994

The purpose of this study is to evaluate the feasibility, advantages/disadvantages of patient-controlled sedation (PCS) compared to anesthesiologist-controlled sedation (ACS) during neurolytic pain block and regional anesthesia. Forty patients were divided randomly into two groups of 20 patients each. Group 1(ACS) received 0.01 $mg{\cdot}kg^{-1}$ intravenous midazolam and 0.5 ${\mu}g{\cdot}kg^{-1}$ fentanyl intravenously by anesthesiologist just before, 30, and 60 minutes after the procedure to acheive sedation; Group 2 (PCS) patients self-administered a mixture of midazolam (0.4 mg) and fentanyl ($20{\mu}g$) using a syringe type infusion pump (Terumo, Japan) to acheive sedation. Considering the dermographics of patients, the types and durations of procedure performed, the level of average sedation the comfort level were similar in both groups. But the doses of midazolam and fentanyl administerd in group 2 were smaller than those in group 1 (p<0.01). Patients in PCS group showed their level of sedation more proper than did those in ACS group. However, patients in ACS group rated their level of comfort higher than did those in PCS group. The findings of this study indicate that PCS using a combination of midazolam and fentanyl is a fafe and effective technique. More studies are, however, needed to determinc the best choice of drug(s), doses, lock-out intervals, and possible use of continuous infusion with patient-controlled sedation.

• KIEAE Journal
• /
• v.4 no.3
• /
• pp.203-210
• /
• 2004

This dissertation identifies and investigates the possible control modes of hybrid ventilation system in applying to general apartments. It evaluates range of hybrid ventilation control modes in terms of indoor air quality, thermal comfort, and energy consumption in a living room and a kitchen of the $1000m^2$ apartment. The TRNSYS simulation program was used for evaluating the following four ventilation types : A ventilation mode relying on only infiltration for supplying air, A natural ventilation mode considering with weather condition, A hybrid ventilation (natural + mechanical ventilation) mode allowing minimum ventilation with no heat exchange, and a hybrid ventilation mode with heat exchange. This study shows the following results. As temperature being controlled by heating cooling equipments, there is without significant difference in thermal performance among ventilation types. Regarding Indoor Air quality, Indoor air contamination level of the hybrid ventilation case consistently keep the lower levels. The hybrid ventilation modes consume more energy by a 49% as compared to the A ventilation mode relying on only infiltration for supplying air. It is caused by the continuous ventilation for keeping good indoor air quality; the increase of energy consumption can be attributable to the increase of the heating energy. Therefore, the heat exchange between indoor and outdoor air is required during heating season in severe weather conditions. During the cooling seasons, Introducing natural ventilation can achieve energy saving by 40 ~ 45%. Thus, it can be an effective strategies for energy saving. Based on these results, a hybrid ventilation system can be suggested as an effective ventilation strategy for archiving high level of indoor air quality, thermal comfort, and energy consumption.

• Korean Journal of Applied Biomechanics
• /
• v.16 no.1
• /
• pp.65-79
• /
• 2006

The purpose of this study was firstly to investigate correctional function of custom semi-rigid foot orthotics for excessively pronated people during gait by observing comfort, navicular movement and leg muscles' activity according to short-term and mid-term wearing duration and secondly to understand positive and/or negative point of view of a recently proposed paradigm related to foot orthotics more profoundly. Sixteen subjects who showed excessive pronation at navicular drop test were recruited for this study. Custom semi-rigid foot orthotics were made fitting for foot characteristics of the subjects by podiatry division of Otto Bock Korea company. While wearing the foot orthotics for two months, comfort of wearing were questioned and vertical navicular movement and electromyography of leg muscles during gait were measured at the condition of both immediately after and 2 months after including a control condition, respectively. The subjects were required to walk on a treadmill at the speed of 1.5m/s and four digital video camera filmed the movement of navicular process at the speed of 60 frames/s. In conclusion, in excessively pronated group continuous increase of comfort from short-term to mid-term wearing of custom foot orthotics is assumed to be closely related with short-term and mid term correctional action, of which are consisted the decrease of the range of navicular drop and navicular raisins- the faster timing of minimum navicular position occurring, and the decrease of leg muscles' activities. This conclusion could lead to positively accept new paradigm related to foot orthotics suggested by Nigg and the author suggest that in the future study the variable which could observe navicular movement would be one of major variables to study preferred path of skeleton in the paradigm.

• The Journal of the Korea Contents Association
• /
• v.15 no.6
• /
• pp.575-588
• /
• 2015

The purpose of this research is to examine the effect the motives for participating in lifelong education and involvement on lifelong education have on the learners' satisfaction from lifelong education, the continuous intention to take courses, and the intention to recommend lifelong education. The results from a quantitative research show that the practical and recreational motives had a high positive correlation to situational involvement in lifelong education and that the relational and goal-oriented motives had a high positive correlation to continuous involvement in lifelong education. Moreover, for satisfaction about teaching methods, practical motives had a relatively higher effect. For satisfaction about facility comfort, recreational motives had a relatively higher effect. For satisfaction about communication, relational motives had a relatively higher effect. For satisfaction about contents' quality, goal-oriented motives had a relatively higher effect. The finding also shows that situational involvement had a relatively higher effect on satisfaction about contents' quality. Continuous involvement had a relatively higher effect on satisfaction about teaching methods.

• Journal of Information Technology Applications and Management
• /
• v.20 no.3_spc
• /
• pp.259-278
• /
• 2013

At the center of the repeating evolution of IT industry, there is mobile computing in the ubiquitous environment, and the increasing usage of smart phones contribute more to its growth. P corporation co-developed with Google and implemented smart work system called SWP for the purpose of 'communication and collaboration with co-workers' beyond the general goal of increasing productivity and comfort of employees. The primary objective of this study is to objectively analyze the influence of the effect factor from end user's perspective and user satisfaction on SWP usage, intention for continuous usage and individual performance. To accomplish this research purpose, this study established research models and hypothesis by collective review about information system success models, and tested the research hypotheses using the structural equation modeling technique by data collected from 320 SWP system users of P corporation. Variations for system satisfaction evaluation standard are 1)SW system usage 2) intention for continuous usage 3) individual performance, effect variations are 1) social factors 2) technical factors 3) combination of social and technical factors. Therefore, this study is about influence factors on success of SWP system and how the factors impact the outcome. The test results of this research model is summarized as follows. Firstly, system user's satisfaction had positive impact on all three; SWP system usage, intention for continuous usage and individual performance. Secondly, social factor 'SWP control system' and technical factor 'information quality' and 'system quality' had positive impact on SWP system user satisfaction, while social factor 'shared value' and technical factor 'service quality' did not have significant effect on user satisfaction. Shared value however, had interactive effect with 'information quality' and 'service quality'. This study is expected to contribute to spread of academic research on smart work system by suggesting a model that can show important factors for corporation while explaining the successful implementation of SWP and its continuous usage.

• KIEAE Journal
• /
• v.7 no.6
• /
• pp.3-8
• /
• 2007

Recently, because of the continuous rise of international oil price, energy saving is strongly demanding. So, Ecological technics of architecture such as use of natural energy have been actively explored in the field of building. In the method of utilizing natural energy, the key point is to saving energy effectively as not lowering the comfort of indoor environment, various systems investigated. Many papers about double skin facade system have been reported, it is announced broadly that the system is very effective in improvement of natural ventilation and indoor thermal environment, and also protecting outdoor sound. The shaft box facade is a special form of box window construction. It consists of a system of box windows with continuous vertical shafts that extend over a number of stories to create a stack effect. The facade layout consists of an alternation of box windows and vertical shaft segments. This research investigated the natural ventilation performance of shaft box type balcony which conform the shaft box type double skin to the exiting balcony construction. First, analyzed various types of exiting apartments, proto-type was decided. By using virtual environment Program, modeling the proto-type, compared the contribution of air temperature and the effect of outdoor air cooling. by this research, we confirmed that shaft box type balcony had many possibility for improvement of indoor environment.

• KIEAE Journal
• /
• v.7 no.5
• /
• pp.81-86
• /
• 2007

The research analyzes the arrangement of boiler and hot water header, the method of radiator pipe setting, hot water supply control, hourly heating situation of each room for underfloor radiant heating systems in Korea and suggests an alternative to improve to efficient heating method. One of the best options for install position of hot water distributor is under kitchen sink which is center point of all rooms, according to previous research of the energy saving strategies. When the radiator pipes are arranged to each individual room instead of bedrooms through livingroom and kitchen, it has energy saving effects. For rooms without occupancy according to a time period, hot water supply method should be intermittent heating rather than continuous heating. For this intermittent heating method, individual control of hot water supply is more practical, and it can lead to massive energy savings. The intermittent heating system has time-lag, so it is more effective in energy saving with mild and comfort condition if the spaces are preheated by automatic control equipment prior to required time.

• Journal of Mechanical Science and Technology
• /
• v.14 no.8
• /
• pp.807-815
• /
• 2000

In this paper, modified discrete time preview control algorithms for active and semi-active suspension systems are derived based on a simple mathematical 4 DOF half-car model. The discrete time preview control laws for ride comfort are employed in the simulation. The algorithms for MIMO system contain control strategies reacting against body forces that occur at cornering, accelerating, braking, or under payload, in addition to road disturbances. Matlab simulation results for the discrete time case are compared with those for the continuous time case and the appropriateness of the discrete time algorithms are verified by the of simulation results. Passive, active, and semi-active system responses to a sinusoidal input and an asphalt road input are analysed and evaluated. The simulation results show the extent of performance degradation due to numerical errors related to the length of the sampling time and time delay.