• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.561-567
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• 2018

This study was carried out to improve the ride quality of high-speed electric multiple unit. Through dynamic analysis of the HEMU-430X, the range of the equivalent conicity with a critical speed of 300 km/h was between 0.05 and 0.25. The initial adopted wheel profile of HEMU-430X was S1002. The equivalent conicity of S1002 with the mileage of more than 40,000 km was about 0.033 and it was confirmed that XP55 is more suitable for stable operation because XP55 has the equivalent conicity of over 0.061. In order to improve ride quality of high-speed electric multiple unit, the change of installation angle of the yaw damper was suggested from $7.35^{\circ}$ to $0^{\circ}$. From sensitivity analysis and optimization, the air spring lateral and vertical stiffness was suggested to be reduced by 30% and the secondary vertical and lateral damper damping coefficient was increased by 50%. By applying this, it was expected that the car body acceleration could be improved by about 20% on average. The HEMU-430X's yaw damper installation angle was changed to $0^{\circ}$ and the damping coefficient of the lateral damper was increased by 30%. When the test run was carried out at the speed of 300 km/h on the Kyungbu high-speed line, the vehicle lateral acceleration had improved by 34.3%. The effect of additional improvement measures proposed in this paper will be tested in the on track test. The riding quality improvement process used in this study can be used to solve ride quality problems that can occur in commercial operation of high-speed electric multiple unit in the future.

• Atmosphere
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• v.23 no.1
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• pp.85-92
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• 2013

We estimate atmospheric radiative heating effect of aerosols, based on AErosol RObotic NETwork (AERONET) and lidar observations and radiative transfer calculations. The column radiation model (CRM) is modified to ingest the AERONET measured variables (aerosol optical depth, single scattering albedo, and asymmetric parameter) and subsequently calculate the optical parameters at the 19 bands from the data obtained at four wavelengths. The aerosol radiative forcing at the surface and the top of the atmosphere, and atmospheric absorption on pollution (April 15, 2001) and dust (April 17~18, 2001) days are 3~4 times greater than those on clear-sky days (April 14 and 16, 2001). The atmospheric radiative heating rate (${\Delta}H$) and heating rate by aerosols (${\Delta}H_{aerosol}$) are estimated to be about $3\;K\;day^{-1}$ and $1{\sim}3\;K\;day^{-1}$ for pollution and dust aerosol layers. The sensitivity test showed that a 10% uncertainty in the single scattering albedo results in 30% uncertainties in aerosol radiative forcing at the surface and at the top of the atmosphere and 60% uncertainties in atmospheric forcing, thereby translated to about 35% uncertainties in ${\Delta}H$. This result suggests that atmospheric radiative heating is largely determined by the amount of light-absorbing aerosols.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.186-188
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• 2014

In recent years, domestic as well as LTE wireless network of Wi-Fi and most used. In addition, mobile-intensive services that used mainly in our society makes it easier, SNS, application (APP), and file downloads. As such, the amount of data requested, while living at the time of mobile users will want to be safe from the earliest. And the wireless network communications mortality (3G, 4G (LTE), LTE-A) and Wi-Fi (802.11 n-2.4 G H z z H a c-5, 802.11 G), and users are mainly used in the death 4G (LTE), communication Wi-Fi, 802.11 n-2.4 GHz are used most frequently. As above, use the wireless network in order to safely and quickly developed the technology of the Li-Fi. Li-Fi light (visible light) technology to communicate with, and Wi-Fi (802.11 n-2.4 G z H) 100 times faster, LTE-A 66 times faster. However, the current Li-Fi to commercialise the big issue exists. In this paper, there are a lot of existing problems in the commercialization of Li-Fi being used in Wi-Fi, and a comparative analysis.

• KSBB Journal
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• v.23 no.1
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• pp.90-95
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• 2008

In this study, a combined process of sequential anaerobic-aerobic digestion (SAAD), fluidized-bed bioreactor (FBBR), and ultrafiltration (UF) for the treatment of small scale food waste leachate was developed and evaluated. The SAAD process was tested for performance and stability by subjecting leachate from food waste to a two-phase anaerobic digestion. The main process used FBBR composed of aerators for oxygen supply and fluidization, three 5 ton reaction chambers containing an aerobic mesophilic microorganism immobilized in PE (polyethylene), and a sedimentation chamber. The HRTs (hydraulic retention time) of the combined SAAD-FBBR-UF process were 30, 7, and 1 day, and the operation temperature was set to the optimal one for microbial growth. The pilot process maintained its performance even when the CODcr of input leachate fluctuated largely. During the operation, average CODcr, TKN, TP, and salt of the effluent were 1,207mg/L, 100mg/L, 50 mg/L, and 0.01 %, which corresponded to the removal efficiencies of 99.4%, 98.6%, 89.6%, and 98.5%, respectively. These results show that the developed process is able to manage high concentration leachate from food waste and remove CODcr, TKN, TP, and salt effectively.

• Journal of the Korean GEO-environmental Society
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• v.5 no.3
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• pp.51-60
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• 2004

In Korea there are recently many attempts to expand a temporary soil nailing system into a permanent soil nailing system since the first construction in 1993. In the soil nailing system, the rigid facing walls act on restraining the deformation of the ground. These are purposed to minimize the damage of adjacent buildings or underground structures. In Korea, to minimize the relaxation of the ground, the soil nailing system in the downtown area is often used experientially together with braced cuts, sheet pile walls, soil cement walls (SCW), or jet grouting walls. However, for the conservative design, the confining effects by the stiff facing have been ignored because the proper design approach of considering the facing stiffness has not been proposed. In this study, various laboratory model tests are carried out to examining the influence the rigidity of facings on the global safety of soil nailing system. Also, the parametric studies using the numerical technique as shear-strength reduction technique are carried out. In the parametric study, the thickness of concrete facing walls is changed to identify the effects of the facing wall stiffness.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.394-404
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• 2015

This study investigated the pharmacodynamics of betaine on the blood profile and short chain fatty acid levels in meat ducks exposed to heat wave. 400 heads of Cherry valley (Anasplatyrhynchos) meat ducks were completely randomized to 5 treatments (4 repetitions each), and were raised for 42 days. They were grouped into T1 (heat wave control group without betaine), T2 (betaine 400 ppm), T3 (betaine 800 ppm), T4 (betaine 1200 ppm), and T5 (normal control group without betaine). Compared to T1, the betaine addition groups showed higher body weight gain at shipment, with T3 showing the highest significant difference. For hematological indictors measured (red blood cells and platelets), the betaine addition groups showed significantly higher values than the heat wave control group. The pH of the former was lower but their electrolytes ($K^+$, $P^+$, and $Cl^-$) were significantly higher compared to the latter. For blood gas concentration, the former showed a significantly higher value than the latter. For the total short chain fatty acids, acetic acid, and propionic acid, the betaine addition groups and group fed broiler-high temperature diet showed higher values than the heat wave control group. On the other hand, the former showed significantly lower values in butyric acid, isobutyric acid, valeric acid, and isovaleric acid than the latter group. These results suggest that betaine has the pharmacodynamics that mediate heat stress, via the maintenance and control of the blood profile, osmotic pressure, gas concentration, and short chain fatty acid, of meat ducks under heat wave.

• Journal of Korea Multimedia Society
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• v.6 no.5
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• pp.928-936
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• 2003

In terms of B2B, business partners require works that define 1h13ir ability to operate business collaboration. The document outlining collaboration is the basis of improving the system of business partner and its interoperability. In addition, the definition of business interaction that is based on the documents demonstrating inter-cooperation of business companies is needed to function interoperability properly, and business trading is performed depending on the documents that define reciprocal action of collaboration. In ebXML, CPP(Collaboration-Protocol Profile) defines one business partner's technical capabilities to engage in electronic business collaborations with other partners by exchanging electronic messages. A CPA(Collaboration-Protocol Agreement) documents the technical agreement between two partners to engage in electronic business collaboration. In this paper, I draw up a plan for a composer system that deals with business collaboration document to ameliorate the interoperability of B2B companies.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.129-132
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• 2003

In this paper, which sees the Strong-ARM SA1110 it used the main CPU and RTP in VoIP system. It will be able to apply the information communication field it embodied. It used the Tynux_box2 with the hardware side and it composed a VOIP system. And it used the RTP which is a real-time protocol in software control portion. The development environment of the paper that used the Target board and a Linux PC for connection used the RS-232C, USB connection, Ethernet LAN. The VoIP the environment for a communication used the wave file in the substitution which changes analog signal with the digital signal. And For the communication of the both sides it used the socket. This paper explained the fact that against a general technique from the operation of VoIP system. Using the Embedded linux development board which explained an operational process of the RTP protocol.

• Korean Journal of Construction Engineering and Management
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• v.6 no.2 s.24
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• pp.80-91
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• 2005

Although construction site photos contain important as_built information, technique and knowledge, there has been lack of frameworks to store and manage construction site photos efficiently and effectively. The problems in site photo management are getting increasingly serious, as digital cameras are adapted as collection tools of site Photos. This research suggests an information framework(named CIIM: Construction Image Information Model) to manage and share construction information based on 5W1H in order to derive construction context, which includes technologies, lessons-teamed and knowledge, from construction site photos, and a site photo management system named CIMS II (Construction Image information Management system II was developed to verify the model. It is expected that the results of this research that are an information framework and an system could help more effective classification, management, search and derivation of context in a construction project.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.66-72
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• 2004

PID control has been well used for several decades. For PID algorithms, some tuning methods are used for selecting PID parameters and with these selected parameters, PID control system is designed. But in some cases various kinds of performance indices are used instead of well-known tuning rules, and so variable type of performance index must be tested so that the designed control system meets the some specifications. For 2 DOF PID controller design this paper presents a linear combinational type of performance indices constituting of index for robust performance, which is obtained by h infinity norm of a weighted complementary sensitivity function, including other time domain indices such as error, energy and changing rate of control input. By numerical methods, the optimal 2 DOF PID parameters are obtained. Therefore various types of 2 degree of freedom PID controllers such as I-PD controller are used so that this two degree of freedom PID controllers may give more desirable output characteristics. Simulations are done with MATLAB m file and mdl files.