• Tunnel and Underground Space
• /
• v.16 no.6 s.65
• /
• pp.451-466
• /
• 2006

Analysis of slope behavior concerning the structural characteristics of field rock mass can be processed by virtue of borehole information of joint orientation and position acquired from DOM drilled core. Anticipated sliding potential of pre-failed rock slope is analyzed and the regional slope instability is investigated by inspecting the hazardous joints and blocks the traces of which is projected on the cut-face. Cross section has been set at the center of rock slope and the traces of both joints and tetrahedral blocks, which potentially can induce the slope failure, are drawn to investigate the failure modes and the triggering mechanism. Automated monitoring system has been established to measure the slope movement and especially, inclinometer has been installed inside DOM borehole to analyze the slope movement by considering the internal rock structure. Algorithms for predicting the slope failure time have been reviewed and the significance of heavy rainfall on the slope behavior has been investigated.

• Nuclear Engineering and Technology
• /
• v.44 no.1
• /
• pp.53-60
• /
• 2012

The aim of this study was to explore the spatial and energy resolutions of a PET scanner that we have recently developed. The scanner, which consists of six detector modules with 1-layer LGSO crystals, has a hexagonal configuration with a faceto- face distance of 86.4 mm between two opposite PET modules; such properties facilitate the imaging of small animals. A $^{22}Na$ point source was employed to estimate horizontal and vertical spatial resolutions. To assess the energy resolution, a uniform $^{18}F$ cylindrical phantom was scanned. A software-based spectrum analysis of list-mode data was used to assign a local energy window centered on the photopeak position for every single crystal. For the image reconstruction, an ML-EM algorithm was used. The spatial resolutions at the center of the scanner were 0.99 mm in the horizontal direction and 1.13 mm in the vertical direction. The energy resolution averaged over each PMT ranged from 13.3%-14.3%, which gave an average value of 13.8%. These results show that this simple system is promising for small animal imaging with excellent spatial and energy resolutions.

• Archives of Plastic Surgery
• /
• v.33 no.4
• /
• pp.445-448
• /
• 2006

Purpose: The nose is the most prominent skeletal feature of the face and is thus prone to frequent injury. Closed reduction of nasal bone fractures can be performed under general or local anesthesia. However, the benefits and the drawbacks in either form of anesthesia chosen are seldom perceived by the surgeon. A retrospective study was performed to assess the differences in the outcome among the two groups subjected to surgery under different type of anesthesia and to introduce our method of local anesthesia and its adequacy. Methods: Two hundred and fifteen patients during a 2-year period were included in the study. 2% Lidocaine mixed with 1:100,000 epinephrine was injected on the anterior ethmoid nerve and the periosteum. Assessment factors included intra-operative adequacy of analgesia, post-operative analgesic requirement and functional and aesthetic outcome of surgery. Results: 19 patients were manipulated under general anesthesia and 196 patients were manipulated under local anesthesia on the anterior ethmoidal nerve and dorsal periosteum. No statistically signigicant variable in performance of surgery could be attributed to the mode of anesthesia employed(p > 0.05). Four patients experienced complications after reduction. One developed septal deviation and three nasal obstruction. But, no secondary operations were needed. Conclusion: Anterior ethmoidal nerve block and dorsal periosteal injection of 2% Xylocaine, combined with topical intranasal 4% lidocaine and epinephrine provided sufficient analgesia comparable to that of general anesthesia.

• Journal of the Korea Concrete Institute
• /
• v.27 no.6
• /
• pp.591-602
• /
• 2015

In this paper, cyclic loading test was performed to evaluate the seismic performance of the steel coupling beam and RC shear wall. The test parameter was reinforcement detail of the shear wall. For the shear wall which was designed in accordance with the current design codes, a premature bearing failure occurred at the face of the wall. On the other hand, the bearing failure of walls was prevented due to the new type of reinforcement details. Test results indicated that the vertical reinforcements were more affected to the shear strength of the coupled shear wall than the horizontal reinforcement. Based on the failure mode, concrete stress distribution above and below flanges of the embedded steel beam was proposed. Assuming proposed concrete stress distribution, load resistance was predicted and it was agree well with test data.

• Journal of the Korea Convergence Society
• /
• v.9 no.9
• /
• pp.47-52
• /
• 2018

Wi-Fi enabled Internet of Things (IoTs) had a substantial impact on society, economy and industry. However wireless connectivity technologies in unlicensed band such as Wi-Fi are vulnerable to interferences. They also face difficulty providing wireless connectivity over long range in dense networks due to the dynamically changed interference effect and asymmetric interference conditions. In this paper, robust acknowledgement transmission scheme is proposed for long range IoTs. According to the proposed scheme, it is possible to control the transmission rate of the transmission success rate of the response frame by adjusting the transmission rate of the response frame when the interference is present asymmetrically. It is also possible to use higher data rate when high quality link is guaranteed. The evaluation results demonstrated the proposed scheme improves the aggregate throughput by at most 9 Mbps when 20 MHz bandwidth transmission mode was adopted.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.18 no.3 s.118
• /
• pp.305-314
• /
• 2007

In this paper, we suggested a CPW-fed UWB antenna with uni-planar sectoral structure. The area where radiation device face ground is designed to have the shape of tapered slot based on exponential function. We modified a rectangular bow-tie dipole structure antenna and thus formed a multi-resonant mode. From this, we expanded the impedance bandwidth and made a feature satisfying VSWR of less than 2 between $3.1\sim10.6GHz$. The test result showed that the return loss less than -10 dB was met in the full-band UWB system and maximum gain of $0.9\sim3.1dB$ was made with the half-power beamwidth of $40.1\sim89.9^{\circ}$ on XY plane(Theta, $Phi=90^{\circ}$) and the full band. By using CPW-fed structure with no ground on the back of the substrate, the suggested antenna is easy to design and its miniaturization is also possible.

• The KIPS Transactions:PartB
• /
• v.13B no.2 s.105
• /
• pp.187-196
• /
• 2006

In 3D animation most people adjust the moving motion of their characters on various terrains by using motion data acquired with the motion capture equipment. The motion data can be used to present real human motions naturally, but the data must be captured again to apply to the different terrains from those given at acquiring mode. In addition, there would be a difficulty when applying the data to other characters, in that case the motion data must be captured newly or the existing motion data must be heavily edited manually. In this paper we propose a unified method to generate human motions of walking and running for various terrains such as flat plane, inclined plane, stairway and irregular face. With these methods we are able to generate human motions controlled by the parameters : body height, moving speed, stride, etc. In the proposed methods, the positions and angles of joint can be calculated by using inverse kinematics, and we calculate the trajectory of the swing leg and pelvis according to the cubic spline. With these methods we were presented moving motions using a model of a human body.

• Journal of the Korean Society for Railway
• /
• v.11 no.5
• /
• pp.513-518
• /
• 2008

Currently, urban areas face congestion problems that diminish personal mobility and freight-transport productivity. An increasing number of experts suggest that separating freight traffic from passenger traffic makes sense in terms of economics, the environment, and safety. Some experts suggest that tube transportation is the solution. The objective of this paper is to evaluate the potential benefits and limitations of tube transportation system as a viable mode of transport that can alleviate congestion on roadways. Specifically, this research employs theoretical and practical method identifying, evaluating, and selecting appropriate freight pipeline systems; evaluating the technical and economic feasibility of tube transportation; and estimating environmental, energy, and safety benefits.

• Tunnel and Underground Space
• /
• v.31 no.6
• /
• pp.415-427
• /
• 2021

This technical report briefly introduced the rock cutting splitting method under development. This method is a method of excavating the rock by splitting the block after the rock cutting process. After designing the cutting geometry of the rock face, the chisel is press-fitted to remove the rock block. At this time, when the cutting block is properly designed, the tensile crack propagates smoothly at the bottom of the rock block. An analytical solution was devised to estimate the indentation force required for splitting rock blocks using fracture toughness mode 1 required for tensile crack growth. The impact force of the hydraulic breaker of the excavator was analyzed, and the grade of the excavator that can be constructed according to the rock block design geometry was analyzed.

• Asia-Pacific Journal of Business
• /
• v.12 no.2
• /
• pp.175-186
• /
• 2021

Purpose - This study intended to identify the effects of varied institutional systems and policies that regulate or define operations of enterprises upon the profitability of private enterprises through case analysis. Design/methodology/approach - The systems and differences in the institution and commodity distribution in Korea and Japan, which define the operation of the "Garak Wholesale Market" and "Ota Wholesale Market". We were examined in the presentthis study, and the statistical data pertinent to the trade volume and profitability of wholesale market corporations that substantially run both markets, were analyzed. Findings - The competition among the corporations that run the "Garak Wholesale Market" substantially is limited due to regulations over the mode of transaction and monopoly of trust thereby significantly higher level of profitability and safety are guaranteed. However, the institutional autonomy that enabled each distributor in the "Ota Wholesale Market" to compete with each other freely caused the distributors therein face difficulties in securing stable profits due to the relatively poor level of profitability resulted from the autonomy. Research implications or Originality - It seems the autonomy in commercial transaction in the "Garak Wholesale Market" in Korea needs to be secured to promote the competition of distributors therein through an amelioration of institutional systems and amendment of relevant laws that prescribe current management of various distributors/operators in the market.