• Earthquakes and Structures
• /
• v.25 no.6
• /
• pp.417-427
• /
• 2023

If the center of mass and center of stiffness or strength of a structure plan do not coincide, the structure is considered asymmetric. During an earthquake, in addition to lateral vibration, the structure experiences torsional vibration as well. Lateraltorsional coupling in asymmetric structures in the plan will increase lateral displacement at the ends of the structure plan and, as a result, uneven deformation demand in seismically resistant frames. The demand for displacement in resistant frames depends on the magnitude of transitional displacement to rotational displacement in the plan and the correlation between these two. With regard to the inability to eliminate the asymmetrical condition due to various reasons, such as architectural issues, this study has attempted to use supplemental viscous dampers to decrease the correlation between lateral and torsional acceleration or displacement in the plan. This results in an almost even demand for lateral deformation and acceleration of seismic resistant frames. On this basis, using the concept of Torsional Balance, adequate distribution of viscous dampers for the decrease of this correlation was determined by transferring the "Empirical Center of Balance" (ECB) to the geometrical center of the structure plan and thus obtaining an equal mean square value of displacement and acceleration of the plan edges. This study analyzed stiff and flexible torsional structures with one-way and two-way mass asymmetry in the Opensees software. By implementing the Particle Swarm Optimization (PSO) algorithm, the optimum formation of dampers for controlling lateral displacement and acceleration is determined. The results indicate that with the appropriate distribution of viscous dampers, not only does the lateral displacement and acceleration of structure edges decrease but the lateral displacement or acceleration of the structure edges also become equal. It is also observed that the optimized center of viscous dampers for control of displacement and acceleration of structure depends on the amount of mass eccentricity, the ratio of uncoupled torsional-to-lateral frequency, and the amount of supplemental damping ratio. Accordingly, distributions of viscous dampers in the structure plan are presented to control the structure's torsion based on the parameters mentioned.

• Journal of Korean Society of Water and Wastewater
• /
• v.20 no.1
• /
• pp.94-103
• /
• 2006

The pollution in closing water can be caused by not only artificial factor like sewage but also natural factor like elution from sediment. In this study we analyzed Sediment Oxygen Demand (SOD) for verification of sediment purification effect and sediment elution experiment as well as general items like COD, TN, TP, SS to complement and assess the effect of sediment and water quality. The experiment result showed that the release rate of OSD system were 4 times and 3 times as large as control for P and Fe respectively. SOD for operated OSD system and control were $12.18gO_2{\cdot}m^{-2}{\cdot}d^{-1}$ and $47.95gO_2{\cdot}m^{-2}{\cdot}d^{-1}$. From water qualities analyzed by COD, TN, TP, SS, chlorophyll-a, the removal efficiency increase of TN, TP, chlorophyll-a and COD were about 10~20%, 40~50% and 10% respectively. In conclusion, OSD can contribute to improvement of both the waterbody and the sediment environment effectively.

• Journal of The Korean Digital Architecture Interior Association
• /
• v.8 no.2
• /
• pp.29-37
• /
• 2008

The purpose of this study was to analyze the customer demand for design development of digital convergence furniture in the living space of the ubiquitous home. This study used the individual survey method and was collected from July 1 to 20, 2008. The frequency and percentage were used for data analysis by SPSS window's 12. The results of the study were as follows: The first, a lot of survey targets were 30-40 years old, university graduates, over 50,000,000 won in annual income and 30-40 pyung in house size. The second, what types of activity were carried out in the living room were acquisition of knowledge>entertainment activity>communication activity>household chores. The third, what types of furniture were used in the living room were A/V furniture>table>sofa>computer table>bookself. The forth, customers preferred to picture telephone service in sociality, home-theater service in entertainment and home appliances remote control service in information service. The fifth, the digital functions which can integrate with the living roon furniture, in the item for A/V furniture, was front door control function which recognizes visitors with the screen. In the item for table was function to search internet and for sofa was self purification function. Finally, the digital convergence furniture is not only for one activity but also for various types of activities that can comprehensively function to materialize the concept of comfortable furniture in the living space.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.11 no.2
• /
• pp.101-107
• /
• 2005

The term 'antimicrobial' packaging encompasses any packaging technique(s) used to control microbial growth in the food product. These include packaging materials and edible films and coatings that contain antimicrobial agents, and also techniques that modify the atmosphere within the package. In recent years, antimicrobial packaging has attracted much attention from the food industry because of the increase in consumer demand for minimally processed, preservative-free products. Reflecting this demand, the preservative agents must be applied to packaging in such a way that only low levels of preservatives come into contact with the food. The film or coating technique is considered to be more effective, although more complicated to apply. New antimicrobial packaging materials are being developed continually. Many of them exploit natural agents, to control common food-borne microorganisms. Current trends suggest that in due course, packaging will generally incorporate antimicrobial agents and the sealing systems will continue to improve. The focus of packaging in the past has been on the appearance, size and integrity of the package. A greater emphasis on safety features associated with the addition of antimicrobial agents is perhaps the next area for development in packaging technology.

• Journal of Electrical Engineering and Technology
• /
• v.2 no.3
• /
• pp.408-412
• /
• 2007

It is almost impossible to secure the reproductibility and stability of a commercial Thick-Film Metal Oxide Semiconductor Gas Sensor since it is very difficult to keep the consistency of the manufacturing environment. Thus it is widely known that the general Semiconductor-Oxide Gas Sensors are not appropriate for precise measurement systems. In this paper, the output characteristic analyzer of the various Thick-Film Metal Oxide Semiconductor Gas Sensors that are used to recognize the air quality within an automobile are proposed and examined. The analyzed output characters in a normal air chamber are grouped by sensor ranks and used to fill out the characteristic table of the Thick-Film Metal Oxide Semiconductor Gas Sensors. The characteristic table is used to determine the rank of the sensor that is equipped in the current air cleaner system of an automobile. The proposed air control system can also adapt the on-demand operation that recognizes the history of the passenger's manual-control.

• Journal of Preventive Medicine and Public Health
• /
• v.31 no.4 s.63
• /
• pp.719-727
• /
• 1998

This study was carried out to assess the relationship between jobstrain, psychosocial distress and homocysteine. The study design was cross-sectional, and included 152 industrial workers in middle sized city. A self-adminstered questionnaire measured general characteristic, job strain and psychosocial distress. Blood was drawn into EDTA tube, and total plasma homocysteine was measured by HPLC. Homocysteine in the high job demand group was sagnificantly higher than that in the low job demand. Cholesterol in the high job control group was significantly higher than that in the low job control. Homocysteine was significantly higher in the high job strain group than that in the other group. Folate and vitamin B12 showed a significantly negative correlation with homocysteine. Multiple regression analysis was used to determine whether the psychosocial distress and other variable contributed to explaining the homocysteine. Stress correlates with the homocysteine.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.5
• /
• pp.1789-1797
• /
• 2017

It is necessary to charge electric vehicles in order to drive them. Thus, it is essential to have electric vehicle charging facilities in place. In the case of a household battery charger, the power similar to that consumed by a household with a basic contract power of 3kW is consumed. In addition, many consumers who own an electric vehicle will charge their vehicles at the same time. The simultaneous charging of electric vehicles will cause the load to increase, which then will lead to the imbalance of supply and demand in the distribution system. Thus, a smart charging scheme for electric vehicles is an essential element. In this paper, simulated conditions were set up using real data relating to Korea in order to design a smart charging technique suitable for the actual situation. The simulated conditions were used to present a smart charging technique for electric vehicles that disperses electric vehicles being charged simultaneously. The EVs and Smart Charging Technique are modeled using the Electro Magnetic Transients Program (EMTP).

• Proceedings of the Korea Contents Association Conference
• /
• 2003.05a
• /
• pp.198-201
• /
• 2003

Changes in internet and network environment make it possible to provide high-quality content services in real time. As demand for digital content is increased, problems related to intellectual property rights are getting more important. Streaming service like video-on-demand solved this problem by preventing content from being saved. But, as the advent of several tools able to save streamed content, the streamed content is not free from these problems any more. So, with security countermeasure like access control, new technologies to control and manage rights for content are needed. One of the solutions is DRM In this paper, we describe a DRM-based streaming service that can send the ASF stream which is the multimedia file format of Microsoft.

• Journal of Power Electronics
• /
• v.18 no.2
• /
• pp.588-603
• /
• 2018

This paper presents the idea of a smart load that can adjust the input power flow based on the intermittent power available from RESs (Renewable Energy Resources) to regulate the line voltage, and draw a constant power from the grid. To this effect, an innovative power flow controller is presented based on a Resistive ES (Electric Spring) in combination with a PEAT (Power Electronics based Adjustable Transformer), which can effectively shape the load power flow at the subnetwork level. With a PEAT incorporated in the step down transformer at the grid side, the proposed controller can supply non-critical loads through local RESs, and the critical loads can draw a relatively constant power from the grid. If there is an abundance of power produced by the RESs, the controller can supply both non-critical loads and critical loads through the RES, which significantly reduces the power demand from the grid. The principle, practicality, stability analysis, and controller design are presented. In addition, simulation results show that the power flow controller performs well in shaping the load power flow at the subnetwork level, which decreases the power demand on the grid. Experimental results are also provided to show that the controller can be realized.

• Proceedings of the KIEE Conference
• /
• 1993.11a
• /
• pp.19-22
• /
• 1993

Demand side management (DSM) is the planning and implementation of those utility designed to influence customer use of electricity in ways that will produce desired changes in the utility's load shape. It is conspicuous that the peak load control of DSM is efficiently adopted. In this paper, the package type air conditioner(A/C) mounted radio controlled switch. During the summer of 1990 KEPCO conducted tests in Seoul areas to determine the economic feasibility of interrupting A/C units for short periods of time during peak load periods. These tests were performed between July 30 and September 20 and were limited to the hours of between 1 and 6 p.m. These tests indicated that each A/C contributes approximately 4.5kW to the system peak and can be switched off 10 minutes out of each 1/2 hour without causing the customer any discomfort. Switching each A/C off for 10 minutes out of each 1/2 hour results in a peak load demand reduction of one kW per unit.