• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.12
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• pp.1096-1102
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• 2013

The useful practical land shall be reserved when an artificial land covers the railway and road. However, the problem is that since the artificial land places directly on the top of noise sources likely on the railway and road there will arise the weak points, noise and vibration. On this study based on creating the artificial land on the top of a railway vehicle base and placing a tenement on that land, it was comprehended the noise influence from the railway car through the simulation. In order to secure the input value for the simulation, at first measured the noise condition of the railway station building and the railway vehicle base. The output value for the railway station building (place A) was around (53.6~57.6) dB(A), the equivalent continuous sound level for an hour, and for the railway station building (place B) it was around (63.7~68.9) dB. The maximum outdoor noise of the tenement on the artificial land was measured as 64.1 dB(A) under the fixed condition on the simulation modeling. The built purpose of placing the artificial land to prevent the noise influence from the railway met the expectation to be less influenced on the tenement. Rather, because of placing the artificial land the noise level on the lower space could be increased so there requires having a noise control.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.8 s.197
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• pp.130-137
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• 2007

The optimized prosthetic mass distribution was a controversial problem in the previous studies because they are not supported by empirical evidence. The purpose of the present study was to evaluate the effect of prosthetic mass properties by modeling musculoskeletal system, based on the gait analysis data from two above-knee amputees. The joint torque at hip joint was calculated using inverse dynamic analysis as the mass was changed in knee and foot prosthetic components with the same joint kinematics. The results showed that the peak flexion and abduction torque at the hip joint were 5 Nm and 15 Nm when the mass of the knee component was increased, greater than the peak flexion and abduction torque of the control group at the hip joint, respectively. On the other hand, when the mass of the foot component was increased, the peak flexion and abduction torque at the hip joint were 20 Nm and 15 Nm, greater than the peak flexion and abduction torque of the control, respectively. The hip flexion torque was 4.71-fold greater and 7.92-fold greater than the hip abduction torque for the knee mass increase and the foot mass increase on the average, respectively. Therefore, we could conclude that the effect of foot mass increase was more sensitive than that of knee mass increase for the hip flexion torque. On the contrary, the mass properties of the knee and foot components were not sensitive for the hip abduction torque. In addition, optimized prosthetic mass and appropriate mass distributions were needed to promote efficiency of rehabilitation therapy with consideration of musculoskeletal systems of amputees.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.10
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• pp.13-19
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• 2007

Location awareness is one of the key functions to build U-city. Recently, many of works for location-aware systems are emerging to commercially apply to on-going large-scale apartment complex. As dwellers or cars being attached with active tags are moving in the U-city complex, the active tags periodically broadcast their own identifiers mu routers fixed along the street or in a building use those information to calculate location of thorn. There are several issues to be considered for such an environment. In this paper we propose i) a new architecture for location-aware system considering such issues ii) technical issues to implement it using active tags, and iii) a mathematical analytic model to investigate overall performance and verify it by comparing with actual experimental results. Through mathematical analysis, we can show that it is more efficient for the routers to send location signals than the tags do. We also show that there are several additional services available in the apartment complex. We conduscted several experiments hi a real ease parking lot to show that our system can locate the location of dwellers or cars.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.121-129
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• 2011

With advances in wireless networks and advent of powerful mobile devices such as smart phones, the demand for mobile IPTV services has been increasing. It is essential to minimize the energy consumption of mobile devices because their battery capacity is limited. In this paper, we therefore propose a new streaming structure in P2P-based mobile IPTV systems to minimize the energy consumption of mobile peers using agent peers. Agent peers can decrease the energy consumption of mobile peers significantly by performing streaming functionality and exchanging control messages for joining and leaving overlay networks in place of corresponding mobile peers. Finally, by simulation experiments using an energy model, we show that our proposed streaming structure can increase the lifetime of mobile peers using agent peers.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.4
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• pp.365-371
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• 2014

A numerical simulation was conducted for the combustion chamber of a 4-step grate-firing boiler for wood pellet fuel. The flame is extended to the exit of combustion chamber, which is reproduced by present numerical method based on a homogeneous reaction model. Flow field from the simulation shows a strong recirculation flow at the upstream corner of the chamber, along which the flame is extended to the exit. These combustion and flow characteristics remain unchanged for partial load operations, which suggest modification of the combustion chamber structure rather than resizing should be effective to improve combustion characteristics. Possible modifications for combustion chamber are suggested such as relocating its exit, increasing the number of grate steps or installing internals such as guide baffles.

• Korean Journal of Geomatics
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• v.1 no.1
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• pp.1-5
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• 2001

This paper presents an investigation into the operational comparison of SPOT triangulation to build GCP library by analytical plotter and DPW (digital photogrammetric workstation). GCP database derived from current SPOT images can be used to other image sensors of satellite, if any reasons, such as lack of topographic maps or GCPs. But, general formulation of a photogrammetric process for GCP measurement has to take care of the scene interpretation problem. There are two classical methods depending on whether an analytical plotter or DPW is being used. Regardless of the method used, the measurement of GCPs is the weakest point in the automation of photogrammetric orientation procedures. To make an operational comparison, five models of SPOT panchromatic images (level 1A) and negative films (level 1AP) were used. Ten images and film products were used for the five GRS areas. Photogrammetric measurements were carried out in a manual mode on P2 analytical plotter and LH Systems DPW770. We presented an approach for exterior orientation of SPOT images, which was based on the use of approximately eighty national geodetic control points as GCPs which located on the summit of the mountain. Using sixteen well-spaced geodetic control points per model, all segments consistently showed RMS error just below the pixel at the check points in analytical instrument. In the case of DPW, half of the ground controls could not found or distinguished exactly when we displayed the image on the computer monitor. Experiment results showed that the RMS errors with DPW test was fluctuated case by case. And the magnitudes of the errors were reached more than three pixels due to the lack of image interpretation capability. It showed that the geodetic control points is not suitable as the ground control points in DPW for modeling the SPOT image.

• Korean Journal of Construction Engineering and Management
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• v.10 no.2
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• pp.46-54
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• 2009

In the early 90s, we had serious shortage of construction engineers for the expansion of construction market. So, Government has established the admitted engineer system in 1995. However, since year 2000, while the engineershortage has been resolved, the opposite situation has occurred: serious over-supply of construction engineers. Therefore, Government announced that would abolish the admitted engineer systems as recognized the existent admitted engineers from 2007. From this point of view, it is critical to make the accurate forecast of number of required construction engineers for providing the basis for the most appropriate policy from 2008 to 2017. This research have developed a construction engineer supply-demand forecast model based on the GDP and construction market analysis. The results of this research will be applied to the basic data that policy planner establishes the supply-demand policy of construction engineers.

• Korean Journal of Construction Engineering and Management
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• v.10 no.2
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• pp.14-25
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• 2009

Many companies have managed their business performance in order to achieve their enterprise purpose. Performance management which applied concept of BSC (Balanced Scorecard) is widely used all over the world. In the construction industry, BSC-based performance management is currently introduced with needs of balanced performance evaluation. However, most companies actually have intermediate level of adapting BSC. It is important to understand its process or and structure. Therefore, this paper is focused on making performance management process and defining each phase of it. In addition, the model and system are established with putting them together. With developing performance process in construction, the construction companies are supposed to detect the deficiencies of the current performance management systems and take some opportunity to be helped for supporting their decision-making. In conclusion, this paper will provide the construction industry with the opportunities to enhance the values of performance management system and construction application.

• Journal of Communications and Networks
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• v.14 no.6
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• pp.662-671
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• 2012

Plug-in hybrid electric vehicles (PHEVs) will be widely used in future transportation systems to reduce oil fuel consumption. Therefore, the electrical energy demand will be increased due to the charging of a large number of vehicles. Without intelligent control strategies, the charging process can easily overload the electricity grid at peak hours. In this paper, we consider a smart charging and discharging process for multiple PHEVs in a building's garage to optimize the energy consumption profile of the building. We formulate a centralized optimization problem in which the building controller or planner aims to minimize the square Euclidean distance between the instantaneous energy demand and the average demand of the building by controlling the charging and discharging schedules of PHEVs (or 'users'). The PHEVs' batteries will be charged during low-demand periods and discharged during high-demand periods in order to reduce the peak load of the building. In a decentralized system, we design an energy cost-sharing model and apply a non-cooperative approach to formulate an energy charging and discharging scheduling game, in which the players are the users, their strategies are the battery charging and discharging schedules, and the utility function of each user is defined as the negative total energy payment to the building. Based on the game theory setup, we also propose a distributed algorithm in which each PHEV independently selects its best strategy to maximize the utility function. The PHEVs update the building planner with their energy charging and discharging schedules. We also show that the PHEV owners will have an incentive to participate in the energy charging and discharging game. Simulation results verify that the proposed distributed algorithm will minimize the peak load and the total energy cost simultaneously.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.3
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• pp.87-94
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• 2012

This study investigates the relationship among locus of control, organizational justice, and job satisfaction. First, this study examines the conceptual structures of organizational justice through field study. Second, organizational justice influences job satisfaction. Third, locus of control influences organizational justice. Literature review identified four factors of organizational justice - distributive, procedural, interpersonal, and informational justice. These identified determinants are expected to have significant relationships with locus of control and job satisfaction. Questionnaires were distributed to 500 members of a manufacturing companies. Among returned questionnaires, 357 samples were used for empirical study. Structural equation analyses based on PLS (partial least square) method were employed to test the hypotheses and the model. The overall adequacy of fit was found to be acceptable. Confirmatory factor analyses supported a 4-factor structure of organizational justice. Distributive, procedural, interpersonal, and informational justice had significant positive effects on job satisfaction. In addition, the effects of locus of control had significant positive effects on organizational justice factors. The results of this study suggest that interpersonal and informational justice should be regarded as important factors of organizational justice to analyze the relationships between locus of control and job satisfaction as well as the relationships among the justice constructs.