• Environmental Engineering Research
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• v.22 no.4
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• pp.363-368
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• 2017

The external diseconomy is hampering sustainable development of the city logistics sector. Burdens on urban environment imposed by the city logistics industry have been put in the spotlight. Based on the principle of Life Cycle Analysis, the comprehensive environment impact for city logistics systems is measured. Firstly, with the city logistics service chain as a whole, its business processes and their interactions with environment are analyzed. In total four types of major environment impact categories are determined. Secondly, case study is made on three city logistics operators located in Jing-Jin-Ji region of China with different business modes, respectively self-operation mode, joint distribution mode and the $3^{rd}$ Party Logistics or 3PL mode. Through analysis of energy consumption and emissions for various business processes, their comprehensive environmental impact values are finally obtained. Thirdly, horizontally comparative analysis is carried out to these three modes of the urban logistics distribution systems. Results show the advantages of the 3PL and the joint distribution modes in developing greener urban logistics distribution. Future research avenues and policy suggestions are proposed finally.

• Journal of Biomedical Engineering Research
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• v.32 no.1
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• pp.1-6
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• 2011

An active training system has been developed to assist the upper extremity function in patients with spasticity. We also evaluated the performance of the developed assistive system in five normal subjects and one hemiplegic patient. The maximum voluntary contraction (MVC) tests for biceps brachii and triceps brachii were performed and the relationship between linear enveloped EMG signal and the elbow joint torque was found. In order to implement an active training, our system was designed to allow isokinetic movement only when the subject generates elbow joint motion larger than the pre-fixed threshold level. The proposed EMG-feedback control method could provide active exercises, resulting in better rehabilitation protocol for spastic patients.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.4
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• pp.51-57
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• 2015

Various hybrid dampers have been developed in Korea to control the vibration due to a wind and earthquake. In order to minimize the installment space, cost and construction process, the new hybrid friction damper is developed. This hybrid damper is composed of several rotary friction components having two frictional joint. Because of these components, the building vibration due to wind and earthquake can be mitigated by hybrid friction damper. In this paper, various dependency tests were carried out to evaluate on the structural performance of two joint rotational friction component of the hybrid damper. Test results show that two joint rotational components do not depend on a displacement and a frequency of forcing but friction coefficients is reducing as a clamping force is increasing.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.104-112
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• 2008

In modern war information system development makes battlefield materialize, and combat factors can maximize combat power exhibition as that apply synchronization. Information system is the core of combat power operation under NCW(Network centric Warfare). This paper proposed a new MOE(Measure of Effectiveness) that can assess the combat power synergistic effect of information system at the theater joint fire operation in NCW environment. This methodology applied the rule of Newton's second law $F=(m{\Delta}{\upsilon})/t{\Rightarrow}(M{\upsilon}I)/T$) Details factor in combat power evaluation is as following. (1) M : Network power; (2) v : Movement velocity; (3) I : Information superiority; (4) T : C2(command and control) time. We applied this methodology to the "JFOS-K(Joint Fire Operating System-Korea) in Joint Chief of Staff" in the real military affair section.

• Journal of Welding and Joining
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• v.10 no.4
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• pp.190-198
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• 1992

Among the variety of welding processes available, the flux cored arc welding is one of the most frequently used process, because of its wide range of application and high productivity. The weld joint tracking is indispensable to improve the flexibility of the arc welding robot application for the flux cored arc welding (FCAW) process. In this study, an arc sensor which utilizes the electrical signal obtained from the welding arc itself was developed for weld joint tracking in FCAW. Because a model of the welding arc in flux cored arc welding was required to develop the arc sensor, a mathematical model was proposed by analysing the welding arc behaviour, and also an experimental model by using the factorial experiment and least square method. For overcoming the fluctuation in the welding current signal during tracking the weld joint, it was fitted to a curve which is inversely proportional to a trace of tip-to-workpiece distance by using the quadratic curve-fitting method.

• Journal of Welding and Joining
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• v.21 no.2
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• pp.57-63
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• 2003

Since new types of vehicles or structures made from thin aluminum alloy are under rapid development and some products are already on the market, welding of aluminium sheet is increasing. MIG(Metal Inert Gas), MIG-Pulse, TIG(Tungsten Inert Gas) welding are the typical Ai welding. MIG welding has the advantage of high speed, but it is difficult to apply to the thin plate, because of bum-through by the high heat input and spatter. MIG-Pulse welding can weld without spatter and burn-through, but when the gap exists at the welding joint, there is quite a possibility of bum-through. TIG welding is difficult to weld at a high speed. AC Pulse welding alternates between DCEP(Direct Current Electrode Positive) and DCEN(Direct Current Electrode Negative). DCEN is higher wire melting rate than DCEP, while lower temperature of droplet than DCEP. In AC Pulse welding, far fixed welding current, wire melting rate increases as the EN ratio increases. For fixed wire feed rate, welding current decreases as the EN ratio increases. Because of these features, the temperature of droplet, the depth of penetration, the width of bead decrease and the reinforcement height increases as EN ratio increases, and these are able to weld at a high speed, lower heat input. It is the purpose of this study that design of AC pulse current waveform for MIG welding of Al sheet and estimation of output characteristic.

• Journal of Welding and Joining
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• v.15 no.1
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• pp.66-80
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• 1997

This paper describes a newly developed arc-sensing algorithm of seam-tracking for FCA W (flux-cored arc welding) horizontal fillet welding. In this algorithm, arc current and the Weighted-Are-Current (WAC) are used to adjust the position of a weld torch in directions of bead throat and weaving, respectively. The WAC, which is newly devised in this study, means that arc current in the vicinity of weaving end is more emphasized than that in the center of weaving. The reason of this is because there usually exists much noise in the center of weaving due to abrupt change of arc length in case some empty gaps exist in a fillet joint Variance analysis was performed in order to check the effect of weld parameters on arc current and the WAC. As a result, the relationships between tip-to-workpiece distance and arc current, and between weaving offset and the WAC were established.To check "the validity of the algorithm, seam-tracking experiments were performed ;mder various welding condition. The result of experiments showed a satisfactory tracking performance in the presence of empty gaps in a horizontal fillet joint.et joint.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.211-214
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• 2006

The outer race of the constant velocity(CV) joint is an important load-supporting automotive part, which transmits torque between the transmission and the wheel. The outer race is difficult to forge, because its shape is very complex and the required dimensional tolerances are very stringent. Therefore, the internet based shape inspection system is developed in this study to provide quick and accurate data through the easy control from users. Proposed system uses mechanical displacement sensors to measure the shape of CV joint that has six inner ball grooves, and commercially available Lab-View program is used to process measured data into the dimensional shape. Developed program provides a simple user interface that enables users real-time access of data measured from industrial production lines. Furthermore, it can exchange measured data via the internet between users and forging system operators. A java applet helped the system connection via internet. A data, IP access, is transmitted to the packet by TCP/IP. Our proposed system has many advantages over current measuring systems including fast and efficient data processing by real-time control, and system flexibility.

• International Journal of Highway Engineering
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• v.19 no.3
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• pp.11-18
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• 2017

PURPOSES : This study investigates the effect on concrete pavement accordance with the curing methods in cool weather and supports the best method in the field. METHODS : Two field tests evaluated the curing methods of concrete pavement in cool weather. Firstly, five curing methods were tested, including normal curing compound, black curing compound, bubble sheet, curing mat, and curing mat covered with vinyl. Concrete maturity was compared from temperature data. Secondly, normal curing compound and curing mat with vinyl, which showed the best performance, were compared in terms of maturity and join condition index. RESULTS:From the field tests, it is an evident that curing mat with vinyl accelerated the concrete strength. Therefore, it is possible to conduct saw-cut works in cool weather, which minimizes damage on concrete at joint. CONCLUSIONS : For concrete pavement in cool weather, using curing mat with vinyl as the curing method could overcome the strength delay. Therefore, strength and durability problems on concrete at joint due to cool weather would be fewer in the future.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.219-221
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• 2007

Recent changes to ubiquitous computing requires more natural human-computer(HCI) interfaces that provide high information accessibility. Hand-gesture, i.e., gestures performed by one 'or two hands, is emerging as a viable technology to complement or replace conventional HCI technology. This paper deals with hand-posture recognition. Hand-posture database construction is important in hand-posture recognition. Human hand is composed of 27 bones and the movement of each joint is modeled by 23 degrees of freedom. Even for the same hand-posture,. grabbed images may differ depending on user's characteristic and relative position between the hand and cameras. To solve the difficulty in defining hand-postures and construct database effective in size, we present a method using a 3D hand model. Hand joint angles for each hand-posture and corresponding silhouette images from many viewpoints by projecting the model into image planes are used to construct the ?database. The proposed method does not require additional equations to define movement constraints of each joint. Also using the method, it is easy to get images of one hand-posture from many vi.ewpoints and distances. Hence it is possible to construct database more precisely and concretely. The validity of the method is evaluated by applying it to the hand-posture recognition system.