• Journal of Korean Association for Spatial Structures
• /
• 제2권1호
• /
• pp.85-92
• /
• 2002

Two way grid single-layer domes are of great advantage in fabrication and construction because of the simple fact that they have only four members at each junction. But, from a point of view of mechanics, the rectangular latticed pattern gives rise to a nonuniform rigidity-distribution in the circumferential direction. If the equivalent rigidity is considered in the axial direction of members, the in-plane equivalent shearing rigidity depends only on the in-plane bending rigidity of members and its value is very small in comparison to that of the in-plane equivalent stretching rigidity. It has a tendency to decrease buckling -strength of dome considerably by external force. But it is possible to increase buckling strength by the use of roofing covering materials connected to framework. In a case like this, shearing rigidity of roofing material increases buckling strength of the overall structure and can be designed economically from the viewpoint of practice. Therefore, the purpose of this paper, in Lamella dome and rectangular latticed dome that are a set of 2-way grid dome, is to clarify the effects of roofing covering materials for increasing of buckling strength of overall dome. Analysis method is based on FEM dealing with the geometrically nonlinear deflection problems. The conclusion were given as follows: 1. In case of Lamella domes which have nearly equal rigidity in the direction of circumference, the rigidity of roofing covering materials does not have a great influence on buckling-strength, but in rectangular latticed domes that has a clear periodicity of rigidity, the value of its buckling strength has a tendency to increase considerably with increasing rigidity of roofing covering materials 2. In case of rectangular latticed domes, as rise-span-ratio increases, models which is subjected to pressure -type-uniform loading than vertical-type-uniform loading are higher in the aspects of the increasing rate of buckling- strength according to the rate of shear reinforcement rigidity, but in case of Lamella dome, the condition of loading and rise-span-ratio do not have a great influence on the increasing rate of buckling strength according to the rate of shear reinforcement rigidity.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• 제19권3호
• /
• pp.669-678
• /
• 2018

This study developed information technology infrastructures for building a driving environment analysis platform using various big data, such as vehicle sensing data, public data, etc. First, a small platform server with a parallel structure for big data distribution processing was developed with H/W technology. Next, programs for big data collection/storage, processing/analysis, and information visualization were developed with S/W technology. The collection S/W was developed as a collection interface using Kafka, Flume, and Sqoop. The storage S/W was developed to be divided into a Hadoop distributed file system and Cassandra DB according to the utilization of data. Processing S/W was developed for spatial unit matching and time interval interpolation/aggregation of the collected data by applying the grid index method. An analysis S/W was developed as an analytical tool based on the Zeppelin notebook for the application and evaluation of a development algorithm. Finally, Information Visualization S/W was developed as a Web GIS engine program for providing various driving environment information and visualization. As a result of the performance evaluation, the number of executors, the optimal memory capacity, and number of cores for the development server were derived, and the computation performance was superior to that of the other cloud computing.

• Journal of Korean Library and Information Science Society
• /
• 제49권1호
• /
• pp.149-171
• /
• 2018

The aim of this study is to investigate the library related campaign promises of the candidates for the heads of metropolitan governments and the superintendents of education between 1st and 6th nationwide local election in Korea. To do this, the library related campaign promises of 346 candidates were analyzed by analysing the official gazettes for elections digitally archived in National Election Commission of Korea. As a result, the campaign promises of the candidates were insufficient both in quality and quantity. The candidates for the heads of metropolitan governments showed low ratio of the library related campaign promises, excessive concentration on construction or installation of libraries and higher preference for small libraries than public libraries. The candidates for the superintendents of education showed relatively balanced distribution of the election promises on library fields. But the campaign promises related public libraries were insufficient and the campaign promises of school libraries did not reflect the major elements of school libraries and the context of school libraries in Korea.

• Journal of the Korean Institute of Landscape Architecture
• /
• 제38권2호
• /
• pp.64-74
• /
• 2010

Freiburg, as the German Capital of the Environment, is well known to Koreans, and relationships with Korean cities are deeply extended. This study attempts to grasp the features of the historical and cultural environment in Freiburg's old town center pedestrian district through the investigation of the historical value of environmental elements and the way they are transmitted along with the components of city identity. Through the literature studies confirms that. The main canal in Freiburg, called Gewerbeknale, is valued both for its existence during the city construction period and for being an infrastructure to supply water to the Bachle(small urban canal) and Brunnen(fountain). In spite of a recipient environment in the middle of the 19th century, the traditional mosaic pavement has a new value as an mediator between citizens and the environment through the adaptations that have occurred in the city. This study has verified the dialectical repetition of crisis and conquest through the historical succession of environmental elements. The historical continuance of environmental elements has a strong influence on the acquisition of sameness and Individuality in city identity factors. The result of this study recommends the historical value of environmental elements that have survived in the urban environment, and verifies the necessity of a concrete strategy for preservation and related practical efforts.

• Journal of Korea Water Resources Association
• /
• 제39권6호
• /
• pp.487-494
• /
• 2006

The flood discharge on the rising limb of a hydrograph at Hwawon station greatly differs from the flood discharge on the falling limb for the same stage. When there is such a big hysteresis, there can be a significant amount of errors in the rated discharge obtained from a simple rating curve. To reduce errors in rated discharges, a looped rating curve was established for Hwawon station in the Nakdong River. In order to compute the deviation between real discharges and simply rated discharges, a simple rating curve was established using the stage and discharge data from the results of a hydraulic channel routing. The relationship between the discharge deviation ${\Delta}Q$ and a product of B and ${\Delta}h/{\Delta}t$ was analysed, where B is the channel topwidth; ${\Delta}h$ is the stage increment; At is the time increment. Strong relation between ${\Delta}Q$ and $B{\Delta}h/{\Delta}t$ was found. The discharges calculated from the relationship show differences by 10 % or less for the 7 observations out of 11 observations in 1997 whose stages exceeds 7 m. The observed discharges for the stages over 9 m in 1998 also show small difference with the discharges estimated from the loop rating curve. Looped rating curve is recommended, instead of the simple rating curve to reduce the errors of rated discharges for gauging stations like Hwawon, which has relatively large loop width.

• Journal of Korea Society of Industrial Information Systems
• /
• 제22권1호
• /
• pp.127-138
• /
• 2017

The Purpose of this Study is to Examine the Effects of Organizational Commitment on Safety Behavior. This Study Built a Exploratory Model that there is Causal Relationship of Organizational Commitment to Employee's Performance that Safety Behavior. Additionally this Study Examine the Moderating Effect of Employee's Job Insecurity on the Effect of Employee Safety Behavior. For the Verification of this Study Model, the Moderating Effects Regression Analysis was Applied to the Surveys of 240 Members of Small and Medium -Sized Construction Industry Employee in Busan. As a Result of the Verification, the First of Organizational Commitment on Organizational Performance has Found that all Three Organizational Commitment of Affective Commitment, Continuance Commitment and Normative Commitment have Impacts Safety Behavior. Second the Study Verifies the Moderating Effect of Employee's Job Insecurity. the Moderating Effect of Employee's Safety Behavior Between the Independent Variable(organizational commitment) and the Outcome Variables has been Analyzed. As a Result, High level of Job Insecurity Employee has been shown to have a Moderating Effect Between the Independent Variable and Safety Behavior.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• 제32권1호
• /
• pp.63-73
• /
• 2014

Recently, researches on DBRN(DataBase Referenced Navigation) system are being carried out to replace GNSS(Global Navigation Satellite System), as weaknesses of GNSS were found that are caused by the intentional interference and the jamming of the satellite signal. This paper describes the gravity gradient modeling and the construction of EKF(Extended Kalman Filter) based GGRN(Gravity Gradient Referenced Navigation). To analyze the performance of GGRN, fourteen flight trajectories were made for simulations over whole South Korea. During the simulations, we considered the errors in both DB(DataBase) and sensor as well as the flight altitudes. Accurate performances were found, when errors in the DB and the sensor are small and they located at lower altitude. For comparative evaluation, the traditional TRN(Terrain Referenced Navigation) was also developed and performances were analyzed relative to those from the GGRN. In fact, most of GGRN performed better in low altitude, but both of precise gravity gradient DB and gradiometer were required to obtain similar level of precisions at the high altitude. In the future, additional tests and evaluations on the GGRN need to be performed to investigate on more factors such as DB resolution, flight speed, and the update rate.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• 제21권7호
• /
• pp.38-45
• /
• 2020

A magnetically levitating capsule train, which runs inside the sub-vacuum tube, can reach ultra-fast speeds by dramatically reducing the aerodynamic drag and friction. The capsule train uses the superconductor electrodynamic suspension (SC-EDS) method for levitation. The SC-EDS method has advantages, such as a large levitation gap and free of gap control, which could reduce the infra-construction cost. On the other hand, disadvantages, such as the large variation of the levitation-guidance gap and small damping characteristics in levitation-guidance force, could degrade the running stability and ride comfort of the capsule train. In this study, a dynamic analytical model of a capsule train based on the SC-EDS was developed to analyze the running dynamic characteristics. First, as important factors in the capsule train dynamics, the levitation and guidance stiffness in the SC-EDS system were derived, which depend non-linearly on the velocity and gap variation. A 3D dynamic analysis model for capsule trains was developed based on the derived stiffness. Through the developed model, the effects of the different running speeds on the ride comfort were analyzed. The effects of a disturbance from infrastructure, such as the curve radius, tube sag, and connection joint difference, on the running stability of the capsule train, were also analyzed.

• Journal of the Korea Organic Resources Recycling Association
• /
• 제7권1호
• /
• pp.53-66
• /
• 1999

Limited landfill area and finance as well as a large generation of food wastes, have called for systematic approaches towards potential cost savings. In this study, the regional management system of food wastes generated from the residential and commercial sources was considered in three cities bounded each other; Changwon, Masan, and Jinhae city. Total thirteen alternatives were established and compared by applying the WRAP (Waste Resource Allocation Program). The following results were obtained: 1. While relatively small amounts were generated from the commercial sources such as cafeteria, restaurants, and market facilities, almost 80% of food wastes were generated from the residential sources. 2. Unit costs for food waste management in three cities were different according to their present situation such as the type and location of major generation sources and treatment facilities. Especially, the highest cost appeared in Jinhae city due to the most expensive construction of coastal landfill site. 3. Considering proper revenue, the whole conversion of food waste into animal feed was selected as the optimal alternative and represented 60% to 74% of the management cost of the whole landfill alternative in all cities. Comparing the other alternatives, composting of food waste was more economical than landfill alternative and the incineration was the most expensive alternative. 4. Some of the regional management systems using common food waste processing facilities together in three cities showed to be more economical than the single management system. Therefore, more detailed research for the regional management systems of food waste was recommended.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• 제19권5호
• /
• pp.146-152
• /
• 2018

In this study, to improve the performance of asphalt mixtures for plastic deformation occurring mainly in Korea, complex modifiers were prepared by mixing powders and liquid type modifiers. The main constituents were powdery diatomaceous earth, mica and carbon black, and liquid type solid 70% SBR latex. The tensile strength ratios for the two asphalt mixtures used in the test were above 0.80 for the Ministry of Land Transportation (2017) asphalt mixture production and construction guidelines. The effects of increasing the tensile strength in the dry state was more than 14% when the composite modifier was added. The deformation rate per minute by the wheel tracking test load was an average of 0.07 to 0.147 for each mixture. The strain rate per minute was improved by the modifier, and the dynamic stability was improved by almost 100% from 295 to 590. In addition, the final settling was reduced from 11.38 mm to 9.57 mm. A plastic deformation test using the triaxial compression test showed that the amount of deformation entering the plastic deformation failure zone at the end of the second stage section and in the third stage plastic deformation section was 1.76 mm for the conventional mixture and 1.50 mm for the complex modifier mixture. The average slope of the complex modifier asphalt mixture mixed with the multi-functional modifier was 0.005 mm/sec. The plastic deformation rate is relatively small in the section where the road pavement exhibits stable common performance, i.e. the traffic load.