• International Journal of Highway Engineering
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• v.2 no.4 s.6
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• pp.111-122
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• 2000

PMS(Pavement Management System) has been developed and/or operated for the freeway and national highway systems in Korea. There is, however, no municipal PMS that is necessary in many cities for efficient management of their roadways. In this study, a municipal Prototype PMS is developed. The Prototype PMS is designed to be operated on PC base. It uses GIS interface for user friendliness that applies color graphics, text and distress pictures to display pavement conditions and rehabilitation information for both current and historical situations. The computer program of the prototype PMS consists of four major functions(inquiry, analysis, data management, and print). Especially, prioritization and M&R(Maintenance and Rehabilitation) alternative selection procedure is designed to be flexible so that the users can modify the decision criteria whenever it is necessary. Database items of the Prototype PMS is carefully selected for the objectives and size of municipal PMS. Reference point method is basically used for the location referencing in the Database. The unit section consists of each loom segment of the road for effective management.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.2
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• pp.67-73
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• 2011

This study aims to develop an economical precast hollow concrete column with high constructability which consists of only splice sleeve and general reinforcing bar without using PC tendons in order to reduce the construction period and cost. With this purpose, this study performed the finite element analysis and tension test by using some variables such as length of sleeve, diameter of rebar and curing method for suggesting a grouting type splice sleeve which is a new type joint rebar and developing an optimized splice sleeve. As a result, the analysis on the tension performance of splice sleeve did not show any destruction caused by pull-out in reinforcing bar but it only occurred destruction of tension bar or bolt shear rupture from the mechanical defect of sleeve. Therefore, the experiment showed high performance in tension of the suggested splice sleeve and verified the application of precast hollow concrete column.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.707-716
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• 2011

It has been applied using cranes or insertion methods to install heavy structures to strengthen existing railway bridges. These methods are uneconomical because of two reasons. The first one is it is required to construct approach roads for heavy equipment and/or working yard. The second one is the electric lines shall be cutoff during construction. Both require additional construction cost and duration. In this study, new transport equipment was developed which can be applied to heavy structures up to 100 ton. Using this method, the heavy structure can be loaded into the new transport equipment at working yard and transported to the working site. This method can be applied, but not limited to railway bridge or roadbed rehabilitation. It was found that the precious construction can be achieved to install heavy structure using this method. The experimental construction to make non-ballast girder bridge composite with new pc deck slab using this method was carried out for Jewon bridge. The example bridge is in extreme condition because it locates above national road #38 within extreme transition curve and has 10 ‰ slope and skew. The experimental construction results were satisfactory both for safety and construction precision.

• Journal of the Korea Concrete Institute
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• v.20 no.3
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• pp.271-282
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• 2008

Specific joint devices composed of end-plates and through bolts are under development to assemble steel beams to PC columns efficiently by dry construction method for the PCS structural system, of which major structural components are precast concrete columns and steel beams. Seismic performance of the joint devices had been evaluated by experimental tests in the previous studies and it was showed that all the performance requirements regarding to strength deterioration, stiffness degradation and energy dissipation capacity were satisfied to the criteria of ACI requirements, but the initial stiffness was not. In order to find out possible causes of the insufficient rigidity of the joint devices and provide the proper measures to improve the performance of the joint accordingly, numerical analyses were carried out by using ABAQUS. Parameters, such as thickness of neoprene pad, conditions of surface between PC column and end-plate, magnitude of pretension forces of through bolts, stiffness of end-plate were taken into consideration. As the result, it was found that the rigidity of the PCS system was negatively affected by the magnitude of initial gaps between PC columns and end-plates, and insufficient stiffness of neoprene fillers and end plates. In order to improve the initial stiffness performance of the joints, measures such as increase of the magnitude of pretension forces on through bolts and increase of the stiffness of end-plate by reducing the bolt pitch and providing adequate stiffeners are recommended.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1726-1732
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• 2008

Injection molding is one of plastic forming technology which can easily mass-produce plastic parts with various and even complex shape. The technology has lots of difficulties in making a good part due to phase change of material, high applied pressure, and fast melt flow speed in the cavity. To overcome the problems, they had to make trial and error method until the CAE(Computer Aided Engineering) could be a tool for concurrent engineering. In this paper, we investigate the optimal design for a plastic DVD tray part by systematic approach of the commercial CAE program. In design, we should consider two objectives which are both dimensional stability and cost-down. The dimension of the part is crucial because the tray should carry a DVD correctly, but the part is too thin to injection-mold easily. In order to improve the moldability, the mold is designed in the form of stack mold which is a kind of 4 hot runner system. In first, we changed the stack-mold system with one hot-runner to cost down, and decided the optimal position of the gate. After that, we investigate the effect of both the layout of cooling channels and the cooling temperature on the shrinkage of the DVD tray. A optimal simulation approach, the gate design is 2Gate#3 and the layout is Case2 cooling line as the optimal temperature of $70^{\circ}C$. The Moldflow and PC+ABS are used for the CAE program and material respectively.

• The Korea Journal of Herbology
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• v.23 no.1
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• pp.85-92
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• 2008

Objectives : This study was performed to efficiently make Black Panax Ginseng (BPG) and evaluate its antitumor activity. Methods : Panax ginseng was steamed at $95^{\circ}C$ for 3 h, dried and steamed again at $115^{\circ}C$ for 6 h. The main ginsenosides of BPG were $Rg_{3}$, $Rk_{1}$ and $Rg_{5}$. Results : Among the saponins in BPG, the amount of ginsenoside $Rg_{3}$ was determined by HPLC method. The 11.48 mg of ginsenoside $Rg_{3}$ was obtained from lg of dried BPG. The crude saponin fraction (CSF) of BPG was tested in vitro for its cytotoxic activities against various human cancer cell lines, such as ACHN, NCI-H23, HCT-15 and PC-3. The CSF of BPG exhibited stronger cytotoxic activity than that of red Panax ginsneng. CSF of BPG exhibited good cytotoxic activities against ACFIN, HCT-15, and PC-3 cell lines with $IC_{50}$ values of 60.3-90.8 ${\mu}g$/ml. However, CSF of BPG did not show any cytotoxic activity against NCI-H23 cell line. Conclusions : BPG produced by new manufacturing is more effective than BPG produced by existing processing in anticancer activity. And new BPG has a possibility of investigation because of high contents of Rg3, Rk1 and Rg5 that have various phisological activities.

• Journal of Korea Water Resources Association
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• v.41 no.10
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• pp.983-993
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• 2008

In recent times, sea level increasing caused by abnormal weather and global warming, sea-sand dredging and complex development causes various kind of erosion damages onto the coastal area in the world. The various types of erosion control and protection methods are applied but there are no signs of fruitful effectiveness. The PC concrete protection block for shore protection structure is practically installed in globally but most of structures in the present day became villainous because of bad accessability. In this study, hydrophilic revetments for control and protection of coastline erosion will be developed in order to make up for a faculty of the shore erosion protection block with better accessibility and excellent protection ability. Experimental measurements were researched to insure for the capacity and facility on reflection coefficient, overtopping volume, and overtopping height characteristics of newly developed shore erosion protection block in model tests. As the result, hydraulic model tests show much excellent than the general step block. Field tests were carried out also to verify through vegetative test on an affinity and construction work test of control-protection on coastline erosion with actual utilization. In the latter case, deposition of sand accumulation occurred in fairly short time at the established reaches and then we can be confirmed to utilize for newly developed block as the revetments for control and protection of coastline erosion.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.344-348
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• 2008

During the last few years, the use of Pre-tensioned spun High strength Concrete(PHC) pile has been gradually increased in many construction sites such as super high-rise and large building construction. there is almost no specific code and/or standard described in the specifications to check verticality for Pre-tensioned Spun High Strength Concrete pile installation process. The most commonly used method for the vortical PHC pile installation is a naked-eye measurement or water level measurement conducted by assistant crew in the construction sites. And recent analysis results of the pile cutting work revealed that it frequently makes a lot of cracks which significantly reduce the strength of the pile and is very labor intensive work, thus requiring a large amount of additional time, costs, and efforts. The main objective of the research is to analize problems and to improvement. measure of PHC Pile Construction. The improvement measure present to the main problem with survey and discussion.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.345-348
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• 2008

Recently, demand is caused that new building environment of value added rising demand on the lines of becoming bigger, manhattanize of structure and becoming high standard of structure in a construction site and influx of advanced foreign nation technique. To satisfy these requirements for alternative, structures applied to the PSC, PC is increasing. Double Tee Slab is possible for long length structure and applied to the method of construction. When assembling Double Tee Slab produced by the factory in the field, becamed carry-out topping concrete in upper, but occurred crack to slab line. There is no structural problem to crack occurred in upper, waterproof in maintenance and repair of structure due to a conservative cause several problems.

• 한국지구물리탐사학회:학술대회논문집
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• 1999.08a
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• pp.202-216
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• 1999

The deep foundation is frequently used for the infrastructures. Since the quality control of the cast-in-place concrete foundations such as CIP piles and slurry walls is not so easy as that of the ready made PC(prestressed concrete) piles, it is necessary to get the information on the integrity of the concrete of the foundation. The depth estimation of foundations whose depths are unknown is also very important in repair and reinforcement works or in safety inspection and assessment to the big structures. The cross-hole sonic logging(CSL) system and the single channel reflection seismic measurement system were developed to test the integrity of pile. The former is well applied to CIP structures, while the later to all kinds of piles with less accurate result compared to that of CSL. To estimate the depth of the deep foundations, parallel seismics, borehole RADAR, and borehole magnetics can be used.