• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.10a
• /
• pp.433-436
• /
• 2009

This study is concerned with an effect of frictional condition in a forward/backward combined extrusion process. Generally, the material flow of the billet is influenced by the corners of the die cavity, the ratio in reduction in area, and thickness ratio of backward can thickness to forward can thickness. In addition, the frictional condition in contact area between the billet and the punch/die also affect the material flow. This paper investigated the effect of frictional condition for variable friction factors. The FEM simulation has been carried out in order to examine the effect of frictional condition. Deformation patterns and flow characteristics were examined in terms of design parameters such as extruded length ratio etc. Die pressure exerted on the die-workpiece interface is calculated by the simulation results and analyzed for safe tooling. Therefore the numerical simulation works provide a combined extrusion process of stable cold forging process planning to avoid the severe damage on the tool.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.1509-1518
• /
• 2011

Shield TBM tunneling method has been getting the spotlight for urban tunneling. It can be minimized the civil complaint during construction and possible safe tunneling. But the settlement has occurred inevitably due to characteristics of shield TBM equipment. For this reason, the civil complaint can occur in urban areas when tunnel with shallow depth passes through neighboring building or residential area. In this study, the occurrence factors of settlement according to shield TBM tunneling and the tendency of ground settlement by strata condition had analyzed. It is suggested that the practical settlement estimation method and minimizing method of ground settlement under simultaneous backfill grouting condition through measurement results and back analysis data using gap parameter.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.2726-2730
• /
• 2011

This paper proposes a CBTC wayside signaling system, which redeems existing track-circuit-based ones by using movement authorities mixed with logical block and moving block. Only one train can be entered into the logical block or the route for existing wayside signaling system. Applying moving block for CBTC system enables the train to get nearer to the preceding one, because its protection mechanism uses train's safe boundary, not fixed block unit. By narrowing the existing route set to switch machine and applying the moving block beyond that area, more than one train can enter into one route area. This paper shows that the efficient train control, i.e. shortening the headway, is possible using the moving block mixed with logical block in wayside signaling system.

• Journal of the Society of Disaster Information
• /
• v.3 no.2
• /
• pp.3-21
• /
• 2007

Every country finds a way to respond a lot of terrors to keep her safe in many ways. Our country, before a terror outbreaks, makes various countermeasures such as strengthening international cooperative systems, strengthening informational ability to countermeasure terror, restricting for terrorists to enter or exit from our country, restricting other countries to input weapons in our country to prevent from terror in the aspect of precaution. A terror is more grave than any other one in behavior, and the criminals have to be punished so much and be discriminated from other ones, too. So, a concept of general crime and terror has to be defined. It is finished in the academic area to some extent, but, it is not sufficient in lawful area so much. Afterwards, it is necessary to establish counter-terror protection laws regulating terror crimes directly. In addition, it is necessary to define concretely and clearly the terror activity and deduce the definition of terrorism.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.33 no.6
• /
• pp.589-594
• /
• 2015

In reflection of road expansion and increasing use rates, interest has blossomed in predicting driving environment. In addition, a gigantic scale of big data is applied to almost every area around the world. Recently, technology development is being promoted in the area of road traffic particularly for traffic information service and analysis system in utilization of big data. This study examines actual cases of road management systems and road information analysis technologies, home and abroad. Based on the result, the limitations of existing technologies and road management systems are analyzed. In this study, a development direction and expected effort of the prediction of road information are presented. This study also examines regression analysis about relationship between guide name and traffic volume. According to the development of driving environment prediction platform, it will be possible to serve more reliable road information and also it will make safe and smart road infrastructures.

• The Korean Journal of Pain
• /
• v.14 no.2
• /
• pp.261-265
• /
• 2001

Radiofrequency thermocoagulation of the gasserian ganglion is a safe procedure that can be controlled well and provides satisfactory pain relief from trigeminal neuralgia with low risk. Here the authors report a case of radiofrequency thermocoagulation performed on a recurred trigeminal neuralgia patient, with particular attention to the V3 area. The patient was treated with microvascular decompression 7 years previous, which lead to untolerable side effects from carbamazepine medication. Following the paresthesia and masseter muscle contracture test at 50 Hz-0.06 volt and 2 Hz-0.5 volt respectively, RF lesionings were performed for 60 sec at $60^{\circ}C$ and 70 sec at $70^{\circ}C$. One week after the procedure, the pain was reduced with a mild hypoesthesia in the V2 area. After 6 months, the pain recurred. Therefore, we performed the same procedure again. After 8-months of follow-up, there has been no pain or complications.

• Korean Journal of Bronchoesophagology
• /
• v.2 no.2
• /
• pp.213-221
• /
• 1996

To evaluate the clinical effectiveness of expandable metallic stents, the stents were implanted under endoscopic guidance with local anesthesia or general anesthesia for maintenance of the constructed subglottic space of trachea. The nine patients with respiration difficulty were subjected for expandable stents. The stenosis of upper airway were due to the framework problem of subglottic trachea and tracheostoma after total laryngectomy. Stents were constructed of 0.4 m stainless steel win in a zigzag configuration of 8 bends. A single stent was 20 m in diameter when fully expanded and 20 mm long. The stents were placed accurately to the stenotic site and followed to the 5 month after stent placement. The stenotic area became narrowed with overgrowing of granuloma in all patients and the metallic stents were removed and the stenotic area reconstructed surgically. As conclusion, this technique for the treatment of the subglottic trachea showed simple and safe, but highly recurred due to overgrowing of granuloma. We suggest that the expandable metallic stent is not encouraging in this study.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1993.03a
• /
• pp.41-48
• /
• 1993

The 2nd phase of Seoul Subway, Lines 5,6,7 and 8, is in progress. To reduce the surface traffic congestion during construction the greater part of the system has been engineered by bored tunnelling. The current tunnelling methodology is based on the New Austrian Tunnelling Method. Serveral collapses have been reported to date. Most of the collapses took place in the area forwed with soft ground. The modes and causes of the collapses were progressive failures in the unsupported surface and sliding failures due to the unfavourable joint direction. The major causes turned out to be the weakness of ground and the sudden influx of ground water from the surface. Some measures to prevent the failures are also presented. To ensure the safe tunnelling ghrough the soft ground the unsupported excavation area has to be minimized and closed as early as possible. Additional support measures such as supporting core, sealing shotcrete, forepoling, spread footing, face rock bolting and grouting should be employed as well depend on ground conditions.

• International Journal of Internet, Broadcasting and Communication
• /
• v.9 no.1
• /
• pp.18-23
• /
• 2017

In 2015, 100-car pileup was happened because the safe distance from the car in front did not be kept due to much fog at YoungJong Bridge in South Korea. This is why the road would be benumbed with cold weather in winter. For this weather condition, if the driver of the car in front changed the lane suddenly or suddenly slammed on the brake in fog or freezing area, the braking distance of the real car has to be 2 or 3 times longer than usual. In this paper, we have simulated the function that warns and notice about the fog area or the freezing one in the road using Arduino sensors and Beacon. Also we propose the intelligent traffic system to protect the accidents in winter.

• The Korean Journal of Emergency Medical Services
• /
• v.5 no.1
• /
• pp.73-88
• /
• 2001

Post these safety tips in any swimming area for all swimmers to read. 1. Always swim with companions. Swim only in area well supervised by lifeguards. 2. Never drink alcohol or use drugs when you're swimming or boating. 3. Always check the water depth. Walk in from shore or ease in from the dock or the edge of the pool. 4. Know the limits of your own swimming abilities. If you're a good swimmer, don't tempt nonswimmers or beginner swimmers to try to keep up with you. 5. Keep any eye on younger swimmers at all times. 6. Learn the proper way to dive in the water safely. Follow guidelines for safe diving. 7. Follow the lifeguards instructions and respect their judgment. Never fake an Emergency. Obey all swimming rules.