• Journal of Biosystems Engineering
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• v.38 no.4
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• pp.295-305
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• 2013

Purpose: Recent research showed that total mixed ration (TMR) feeding for pigs improved the productivity and reduced feed cost and manure odor. An automatic TMR feeding system was developed for this study because the conventional feeder cannot deliver the TMR containing roughage. Methods: Conventional feeding systems and physical properties of TMR were surveyed, and performance tests of the conventional feeder were conducted to develop a TMR feeder. Based on the TMR feeder was developed and installed, driving, measuring weight, radio frequency identification (RFID) reading, and discharging test for feeding were conducted to ensure the performance. Results: Moisture content, density, and angle of repose of the TMR 1 (mixture of 30% cut IRG silage and 70% concentrates) were 31.6%, 387 $kg/m^3$, and $51^{\circ}$, respectively. Moisture content, density, and angle of repose of the TMR 2 (mixture of 45% concentrates, 30% cut IRG silage and by-products, 10% bean curd refuse, 10% others, and 5% fermenter) were 22.2%, 544 $kg/m^3$, and $50^{\circ}$, respectively. The coefficient of variation (C.V.) of conventional concentrate feeding were 1.9~4.1%, and C.V. of TMR containing 1~3% cut IRG roughage feeding by conventional feeder were 9~42%. The conventional disc type feeder was not suitable for TMR feeding because the supply unit was clogged. The C.V. of TMR 1 was 0.6~7.9% when 0.5~10 kg of the TMR supplied, and it was suitable for feeding grow-finish pigs and sows. On the contrary, the C.V. with TMR 2 was 28% when 0.5 kg of the TMR supplied, and it was not suitable for feeding sows. Conclusions: The TMR feeder developed in this study was suitable for feeding grow-finish pigs because the feeder performed stably with over 5.0 kg feed. However, the feeder showed a lack of accuracy for feeding sows because the amount of each feed was more than 0.5 kg per a feeding. Therefore, the improvement of outlet structure for accurate feeding is needed for sow feeding.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.441-446
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• 2008

This study was conducted to determine the effect of heat stress on laying hen performance during summer. A total of 180 Hyline-brown layers, 98 days of age, were housed in a enclosed house. The daily maximum temperature in the house was ranged $26{\sim}36^{\circ}C$. The egg production was markedly fallen than other days when daily maximum temperature in the layer house became more than $33^{\circ}C$. As water intake and feed intake increased to $490\;mL\;bird^{-1}\;day^{-1}$ and $240\;g\;bird^{-1}\;day^{-1}$, the egg production soared. But it was hardly increased more than them. Based on these results, layer house roof should be amply insulated to improve the egg production of layers. If not insulated, the shade curtain should be installed above roof and cool water sprayed before and after 2 p.m. And layers should be provided cool drinking water of about $15^{\circ}C$ in the day time.

• Journal of Korean Society of Disaster and Security
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• v.10 no.1
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• pp.85-90
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• 2017

The purpose of this study is to investigate the effect of vertical and horizontal refraction on the lower part of the power supply and control system of various facilities and machinery that use electricity, so that the power distribution system, which is an important electric facility installed in buildings and public facilities, Type earthquake resistant pads to protect the substructure and prevent short-circuiting on the upper part of the system. The GR-63-CORE (Scale 8.3 class) It is earthquake disaster prevention and disaster prevention technology that satisfies seismic performance. As a research result, it is possible to protect the electricity and communication infrastructure, which can contribute to shortening the time for recovering the electric facilities to the normal state in case of an earthquake, and preventing the fire caused by the destruction of the electricity supply facility in case of an earthquake. As a result, it is possible to minimize the spread of fire that occurs when a large-scale earthquake occurs and to minimize the damage of people and damage to property, and it can contribute to the securing of electric infrastructure that enables citizens to quickly recover to daily life even after suffering a major earthquake. In addition, the technology can be applied to ensure the seismic resistance of the equipment in the communication and computer room, and it can be applied to various fields where the facility function can be stopped due to the shaking of the earthquake base.

• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.101-111
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• 2006

In case of drilled shafts installed by drilling through soft overburden onto a strong rock, the piles can be regarded as end-bearing elements and their working load is determined by the safe working stress on the pile shaft at the point of minimum cross-section or by code of practice requirements. Drilled shafts drilled down for some depth into weak or weathered rocks and terminated within these rocks act partly as friction and partly as end-bearing piles. The base resistance component can contribute significantly to the ultimate capacity of the pile. However, the shaft resistance is typically mobilized at considerably smaller pile movements than that of the base. In addition, the base response can be adversely affected by any debris that is left in the bottom of the socket. The reliability of base response therefore depends on the use of a construction and inspection technique which leaves the socket free of debris. This may be difficult and costly to achieve, particularly in deep sockets, which are often drilled under water or drilling slurry. As a consequence of these factors, shaft resistance generally dominates pile performance at working loads. The efforts to improve the prediction of drilled shaft pile performance are therefore primarily concerned with the complex mechanisms of shaft resistance development. In this study, the numerical analyses are carried out to investigate the behavior characteristics of side of rock socketed drilled shafts varying the loading condition at the pile head. The difference of behavior characteristics of side resistance is also evaluated with the effects of modelling of asperity.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.177-183
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• 2005

The effluent quality is directly affected by the separation of biological solids in a final clarifier because the majority of discharged $BOD_5$ and SS are virtually dependent on the results of biological solids in the sedimentation tank effluent. If a final clarifier is effectively designed and operated, the desired goal of clarification for wastewater can be achieved together with the cost reduction in the treatment of wastewater. To this end flow characteristics and the removal efficiency of SS are numerically investigated especially by the change of the inlet position and the installation of baffle to improve the performance of a rectangular final clarifier. The 2-D computer program developed in a rectangular coordinates has been successfully validated against experimental residence time distribution(RTD) curves obtained by tracing radio-isotope. The lowering of the inlet position weakens the density current and induces the settling of SS in the front zone of a clarifier. Thus the decreased traveling distance of the sludge increases the removal efficiency of SS in the effluent. The inlet baffle installed in the front region of clarifier prevents the short circuiting flow and induces to flow into the dense underflow, which eventually improves the effluent quality. In the case of lower inlet position, however, installation of baffle results in degradation of effluent quality. Consequently it is strongly recommended that in-depth numerical study be performed in advance for optimizing a clarifier design and retrofitting to improve effluent quality in a final clarifier.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.4
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• pp.739-751
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• 2014

We are using our smartphone for our business as well as ours lives. Thus, user's privacy data and a company secret are stored at smartphone. By the way, the saved data on smartphone database can be exposed to a malicous attacker when a malicous app is installed in the smartphone or a user lose his/her smartphone because all data are stored as form of plaintext in the database. To prevent this disclosure of personal information, we need a database encryption method. However, if a database is encrypted, it causes of declining the performance. For example, when we search specific data in condition with encrypted database, we should decrypt all data stored in the database or search sequentially the data we want with accompanying overhead[1]. In this paper, we propose an efficient and searchable encryption method using variable length bloom filter under limited resource circumstances(e.g., a smartphone). We compare with existing searchable symmetric encryption. Also, we implemented the proposed method in android smartphone and evaluated the performance the proposed method. As a result through the implementation, We can confirm that our method has over a 50% improvement in the search speed compared to the simple search method about encrypted database and has over a 70% space saving compared to the method of fixed length bloom filter with the same false positive rate.

• Journal of the Korea Institute of Building Construction
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• v.20 no.5
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• pp.449-457
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• 2020

Due to the improvement of living standards and avoidance of the 3D industry, it is difficult to find young and competent domestic workers at construction sites, and most foreign workers are contributing to the replacement, but the quality is still deteriorating due to lack of skilled workers and aging. Precast method is a method that make members in factory and assembles them on site, which can be expected to improve labor force and quality. This study is intended to provide basic data for the development of hang-type PC beams that can be applied to the determination of the field application of developed PC beams. The U-type connecting material is installed on both ends of the hang-up PC beam, and the role of the U-type connecting material is very important because it is a simple construction method through the U-type connecting material. In addition, the performance of the U-type connecting material will determine the performance of the hang-type PC beam as the final destruction occurs in the hang-type PC beam. The material properties of U-type connecting material were identified through structural experiments, and the end test corresponding to the partial experiment was conducted based on the material test results identified. Finally, the final design value of PC beams was proposed through structural experiments for application to the site.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.5
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• pp.465-474
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• 2008

The real-time hybrid testing method(RT-HYTEM) is a structural testing technique in which the numerical integration of the equation of motion for a numerical substructure and the physical testing for an experimental substructure are performed simultaneously in real-time. This study presents the quantitative evaluation of the seismic performance of a building structure installed with an passive and semi-active MR damper by using RT-HYTEM. The building model that was identified from the force-vibration testing results of a real-scaled 5-story building is used as the numerical substructure, and an MR damper corresponding to an experimental substructure is physically tested by using the universal testing machine(UTM). The RT-HYTEM implemented in this study is validated because the real-time hybrid testing results obtained by application of sinusoidal and earthquake excitations and the corresponding analytical results obtained by using the Bouc-Wen model as the control force of the MR damper respect to input currents were in good agreement. Also for preliminary study, some semi-active control algorithms were applied to the MR damper in order to control the structural responses optimally. Comparing between the test results of semi-active control using RT-HYTEM and numerical analysis results show that the RT-HYTEM is more resonable than numerical analysis to evaluate the performance of semi-active control algorithms.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.412-417
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• 2015

The IMO MEPC has been increasingly strengthening the emission standard for marine environment protection. In particular, nitrogen oxide (NOx) emissions of all ocean-going ships built from 2016 will be required to comply with the Tier-III regulation. In this study, a vanadia based SCR (Selective Catalytic Reduction) system developed for ship application was installed on a diesel engine for power generation of the training ship T/S SAENURI in Mokpo National Maritime University. For the present study, the exhaust pipeline of the generator diesel engine was modified to fit the urea SCR system. This study investigated the NOx reduction performance according to the two kind of injection method of urea solution (40%): Auto mode through the PLC (Programable Logic Control) and Manual mode. We were able to find the ammonia slip conditions when in manual mode method. So, the optimal urea injection quantity can be controlled at each engine load (25, 35, 50%) condition. It was achieved 80% reduction on nitrogen oxide. Furthermore, we found that the NOx reduction performance was better with the load up-down (while down to 25% from 50%) than the load down-up (while up to 50% from 25%) test.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.3 s.49
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• pp.85-100
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• 2006

This paper proposes an optimal design method of linear viscous dampers for the seismic performance of two adjacent structures with different heights. Accordingly, connection method using diagonal bracing between two floors and connection method between two structures are considered, and the effectiveness of the latter method is confirmed through the comparison of the frequency response functions with respect to damping capacity. Moreover, optimal damping to minimize the response of the adjacent structures in the frequency domain is found. The sensitivity of natural frequency and modal damping according to the damper capacity at each floor is obtained for the optimally designed system. From the sensitivity analysis, the modal damping is evaluated to be very sensitive to the damper installed at higher floor. Therefore, sensitivity-based damping distribution method is proposed. Diagonal bracing connection method, uniform distribution method and sensitivity-based distribution method are compared to each other in terms of seismic performance. The comparative results demonstrate that the proposed method is an effective seismic design method for the adjacent structures.