• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.3
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• pp.233-238
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• 2014

In case of the slender mass concrete like attached wall, retaining wall and bridge tower, the low heat cement and the control joint are mainly used for thermal cracking control. However, even if these cracking control methods are considered, it is impossible to control thermal cracks perfectly, because the external restraint is largely in these mass concrete. Because these cracks occurring in slender mass concrete members almost penetrate concrete member, the special cracking control is demanded in these mass concretes. The vertical pipe cooling method improving existing pipe cooling method was developed for the active thermal cracking control of slender mass concrete, and applied at the field attached wall. In results, the maximum temperature dropped more than $10^{\circ}C$ by vertical pipe cooling method, and the cracks decreased about more than 50%.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.4
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• pp.1-23
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• 2017

Organizational culture among flight crews has a profound impact on the individual attitude and behavior of member flight crews, and active training is conducted focusing on improving flight crews' Crew Resource Management(CRM) performance. However, adequate research and training on the relationships between flight crew's individual culture and CRM performance have not been conducted. Hence, this study examined the effect of individual cultural values on CRM performance and the moderation effect of psychological safety, with captains and first officers working for commercial airlines as participants. For the factors related to individual cultural value scale, power distance had no significant effect on CRM performance, uncertainty avoidance had a significant negative effect, and individualism had a significant positive effect. With regard to the moderation effect of psychological safety on the relationships between individual cultural values and CRM performance, a significant interaction was found between power distance and CRM performance, but not between uncertainty avoidance and CRM performance, or between individualism and CRM performance. Power distance and CRM performance exhibited a strong negative correlation in case of low psychological safety. Compared to existing research measuring the cultural characteristics of pilot groups on a national or organizational culture level, this study is uniquely valuable in that it also covers the relationship between individual cultural values of commercial airline flight crews and CRM performance.

• Journal of Advanced Navigation Technology
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• v.15 no.5
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• pp.808-822
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• 2011

In the subject experiment of this paper, contrary to the existing thesis about the emotional labor of people in the face-to-face service industry, I have chosen call center agents as they are primary first point of contact with customers in the airline industry. The main purpose of this experiment is to understand the relationship in between workplace burnout and emotional labor. In this study, I have investigated the following concepts; the effect of mediation on emotional labor, the different levels of emotional labor, and recommendations for improvement of competitive power to the call center agent as a member of the organization. The main results of experiment are as follows. First, the emotional labor given by the airline call center agents affects the rate of burnout. Second, support from workplace superiors showed that mediation had an effect on the relationship between emotional labor and burnout, however support from co-workers had no effect whatsoever. It is hope that this paper would supply information to give a competitive edge for airline call centers and their agents.

• Journal of the Korean Society of Safety
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• v.21 no.3 s.75
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• pp.73-80
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• 2006

Generally beam design depends on the yielding and maximum strength of each member varying with its section shape. Web plate of H-shape beam has not been substituted with glass plate, because it is known that its strength and heat properties are different and it is limited to substitute the existing steel web with glass element. Ceiling height of each room should be decreased with more than 60-80cm due to the beam. Differently from this condition, glass web beam has a good point to see through it and sunshine can be penetrate into the other size especially when it is installed as of outside wall. And also, it can be safer due to controlling room inside easier, if the strength is applicate. This study is to show some applicability after finding out the properties using the test. The test members with a size of $1,600{\times}200{\times}300{\times}9mm$ being SS41 rolled steel having THK 9mm flange while having 8,10mm and reinforced glass 12mm thickness is bonded with epoxy bond under the condition of temperature $28^{\circ}C$, humidity 50%, bonding power 24Mpa. It is show reinforced glass has 5 times of fracture stress more than the common glass but $50{\sim}150%$ difference between these 2 kinds of glass was shown. Reinforce glass did not support the original upper flange after fracture but the common glass did the upper flange after unloading. Generally reinforced glass is stronger than the common one but the common glass having a part of crack on it, compared with reinforced glass having the overall fracture could be more useful in case of needing ductility.

• Journal of Korean Society of Steel Construction
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• v.16 no.1 s.68
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• pp.123-134
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• 2004

In this research, a multilevel decomposition technique to enhance the efficiency of the configuration optimization of truss structures was proposed. On the first level, the nonlinear programming problem was formulated considering cross-sectional areas as design variables, weight, or volume as objective function and behavior under multiloading condition as design constraint. Said nonlinear programming problem was transformed into a sequential linear programming problem. which was effective in calculation through the approximation of member forces using behavior space approach. Such approach has proven to be efficient in sensitivity analysis and different form existing shape optimization studies. The modified method of feasible direction (MMFD) was used for the optimization process. On the second level, by treating only shape design variables, the optimum problem was transformed into and unconstrained optimal design problem. A unidirectional search technique was used. As numerical examples, some truss structures were applied to illustrate the applicability. and validity of the formulated algorithm.

• Steel and Composite Structures
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• v.11 no.5
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• pp.423-434
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• 2011

Tongwamen Bridge is a critical link between Dongmen Island and the land in Shipu town, Zhejiang province, China. It is a 238 m span, half-through, concrete-filled steel tubular (CFST) X-type arch bridge. The width of the deck is only 10 m, yielding a width-to-span ratio of 1/23.8. The plane truss type section rib was adopted, which made of two CFST chords and web member system. The lateral stability is the key issue to this bridge. However, the existing researches on Tongwamen Bridge's lateral stability are all the deterministic structural analysis. In this paper, a new strategy for positioning sampling points of the response surface method (RSM), based on the composite method combining RSM with geometric method for structural reliability analysis, is employed to obtain the reliability index of lateral stability. In addition the correlated parameters were discussed in detail to find the major factors. According to the analysis results, increasing the stiff of lateral braces between the arch ribs and setting the proper inward-incline degree of the arch rib can enhance obviously the reliability of lateral stability. Moreover, the deck action of non-orienting force is less than the two factors above. The calculated results indicate that the arch ribs are safe enough to keep excellent stability, and it provides the foundation that the plane truss rib would be a competitive solution for a long-span, narrow, CFST arch bridge.

• Steel and Composite Structures
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• v.17 no.4
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• pp.497-516
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• 2014

The ultimate carrying capacity of axially loaded welded square box section members made of medium and high strength steels (nominal yield stresses varying from 345 MPa to 460 MPa), with large width-to-thickness ratios ranging from 35 to 70, is analyzed by finite element method (FEM). At the same time, the numerical results are compared with the predicted results using Direct Strength Method (DSM), modified DSM and Effective Yield Strength Method (EYSM). It shows that curve a, rather than curve b recommended in Code for design of steel structures GB50017-2003, should be used to check the local-overall interaction buckling strength of welded square section columns fabricated from medium and high strength steels when using DSM, modified DSM and EYSM. Despite all this, EYSM is conservative. Compared to EYSM and modified DSM, DSM provides a better prediction of the ultimate capacities of welded square box compression members with large width-thickness ratios over a wide range of width-thickness ratios, slenderness ratios and steel grades. However, for high strength steels (nominal yield strength greater than 460 MPa), the numerical and existent experimental results indicate that DSM overestimates the load-carrying capacities of the columns with width-thickness ratio smaller than 45 and slenderness ratio less than 80. Further, for the purpose of making it suitable for a wider scope, DSM has been modified (called proposed modified DSM). The proposed modified DSM is in excellent agreement with the numerical and existing experimental results.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.487-489
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• 2007

In this paper chemical process plant information is addressed to be standardized. The chemical process plant information has complexities in the context of its various types such as functions, shapes, connectivity etc. as well as its usages such as design, construction, operation, maintenance and so on. It was well known that the standard should be made by its users themselves to be used widely. The chemical process industry oriented ISO 15926 RDL (Systems and integration of life-cycle data for oil and gas production facilities : Reference Data Library) can provide the methodology for exchanging and sharing of plant equipment information, which will be developed through integrating existing standards such as ISO 10303 AP221, AP231, AP227. The PCA (Posc Caesar Association) which is located in Oslo, Norway, has the initiative in developing ISO 15926. Korea is a member of PCA and takes part in proposing and reviewing the new standard. The trends and prospects for the standard of chemical process plant information are addressed.

• Journal of Korea Multimedia Society
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• v.14 no.9
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• pp.1138-1151
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• 2011

Sensor network clustering scheme is an efficient method that prolongs network lifetime. However, when it is applied to an environment in which collected data of the sensor nodes easily overlap, sensor node unnecessarily consumes energy. Accordingly, we proposed a data prediction scheme that sensor node can predict current data to exclude redundant data transmission and to minimize data transmission among the cluster head node and member nodes. Our scheme excludes redundant data collection by neighbor nodes. Thus it is possible that energy efficient data transmission. Moreover, to alleviate unnecessary data transmission, we introduce data prediction graph whether transmit or not through analyze between prediction and current data. According to the result of performance analysis, our method consume less energy than the existing clustering method. Nevertheless, transmission efficiency and data accuracy is increased. Consequently, network lifetime is prolonged.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6A
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• pp.617-625
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• 2011

In wireless sensor networks, data dissemination protocols have been proposed for mobile sink groups that are characterized by geographically staying closely and collective movement. They usually exploit flooding technology for mobility supporting and data delivery guarantee. However, it causes the excessive energy consumption of all sensor nodes in the group region due to data delivery participation. Moreover, the costs of the flooding would become higher in proportional to the group region. In this paper, we propose an energy efficient data dissemination scheme that resolves these problems. The virtual infrastructure called a 'pipe' is used as a rendezvous area. A source delivers data to the pipe, from which member sinks in the group retrieve it directly. Simulation results showed that this solution has better performance than existing protocols in terms of energy consumption as it reduces the number of regional flooding and eliminates unnecessary data flooding.