• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.9
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• pp.1395-1403
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• 1993

Protocol conformance is crucial to inter-operability and cost effective computer communication. Given a protocol specification, the task of checking whether an inplementation conforms to the specification is called conformance testing. The efficiency and fault coverage of conformance testing are largely dependent on how test cases are chosen. Some states may have more one UIO sequence when the protocol is represented by FSM (Finite State Machine). The length of test sequence can be minimized if the optimal test sequences are chosen. In this paper, we construct the depth-tree to find the maximum overlapping among the test sequence. By using the resulting depth-tree, we generate the minimum-length test sequence. We show the example of the minimum-length test sequence obtained by using the resulting depth-tree.

• Korean Journal of Computational Design and Engineering
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• v.5 no.2
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• pp.175-183
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• 2000

Proposed in this paper is a model-bated AFA (automatic feedrate-adjustment) method for maintaining smooth cutting-loads (i.e., cutting-force) during 2D-profile milling. Before the cutting-force model was established, some assumptions were verified through a series of preliminary cutting experiments (The results found that the curving-force was independent of the cutting speed and the cutting action at the cutter bosom). From the data obtained during the main cutting experiments, a “chip-load/cutting-force model”representing the cutting-force as a function of the chip-load (i.e., effective cutting-depth) and a feedrate is proposed. Based on the model. an AFA scheme for maintaining smooth cutting-force by adjusting the feedrate (i.e., F-code) according to the changes in chip-load was proposed. To check the validity of the proposed AFA scheme. another set of cutting experiments was conducted by using feedrate-adjusted NC-data while monitoring the actual machining processes using an accelerometer. The experimental results showed that the proposed AFA-scheme was quite effective.

• Progress in Medical Physics
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• v.2 no.2
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• pp.155-160
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• 1991

We have studied the effective point of measurement for cylindrical ion chamber in water phantom for medical electron beams. Markus parallel plate chamber water phantom are used for the measurement of depth dose to determine the depth of the effective point of measurement for various energies(for electron 6MeV, 9MeV, 12MeV, 16MeV, and 20MeV; Co-60; for photon 6MV, 15MV). Cylindrical ion chambes(PTW233643 with r=2.75mm, PR-05P with r=2mm, and PM30 wiht r=15mm are used for the measurement of depth dose by same mtethod and the values of d$\_$50/ and R$\_$p/ obtained by three cylindrical chambers were compared with those of a flat chamber. From this we could evaluate the effective measuring points of cylindrical ion chamber. The effective point of measurement was estimated as 0.4～0.6r shifted toward surface from the center of the chamber for electron beam, 0.3～0.7r for $\^$60/Co X-ray.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.2
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• pp.155-160
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• 2014

In this paper, an algorithm using RGB-depth camera is proposed to detect smoke in interrior. RGB-depth camera, the Kinect provides RGB color image and depth information. The Kinect sensor consists of an infra-red laser emitter, infra-red camera and an RGB camera. A specific pattern of speckles radiated from the laser source is projected onto the scene. This pattern is captured by the infra-red camera and is analyzed to get depth information. The distance of each speckle of the specific pattern is measured and the depth of object is estimated. As the depth of object is highly changed, the depth of object plain can not be determined by the Kinect. The depth of smoke can not be determined too because the density of smoke is changed with constant frequency and intensity of infra-red image is varied between each pixels. In this paper, a smoke detection algorithm using characteristics of the Kinect is proposed. The region that the depth information is not determined sets the candidate region of smoke. If the intensity of the candidate region of color image is larger than a threshold, the region is confirmed as smoke region. As results of simulations, it is shown that the proposed method is effective to detect smoke in interior.

• Geomechanics and Engineering
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• v.5 no.5
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• pp.447-462
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• 2013

An analysis model for predicting the tip bearing capacity of drilled shafts in cohesionless soils is improved in this study. The evaluation is based on large amounts of drilled shaft load test data. Assessment on the analysis model reveals a greater variation in two coefficients, namely, the overburden bearing capacity factor ($N_q$) and the bearing capacity modifier for soil rigidity (${\zeta}_{qr}$). These factors are modified from the back analysis of drilled shaft load test results. Different effective shaft depths and interpreted capacities at various loading stages (i.e., low, middle, and high) are adopted for the back calculation. Results show that the modified bearing capacity coefficients maintain their basic relationship with soil effective friction angle ($\bar{\phi}$), in which the $N_q$ increases and ${\zeta}_{qr}$ decreases as $\bar{\phi}$ increases. The suggested effective shaft depth is limited to 15B (B = shaft diameter) for the evaluation of effective overburden pressure. Specific design recommendations for the tip bearing capacity analysis of drilled shafts in cohesionless soils are given for engineering practice.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.10
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• pp.694-701
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• 1988

Distributed-type railguns are designed to maintain the armature current and the length between the armature and the current-feed region nearly constant with time. This paper deals with factors affecting current distribution, effective resistance and effective skin depth in the rail of a distributed-type railgun. Analytical solutions for the current distributions and resistance in the rail are presented for a simple two-dimensional model under steady-state contions. For diffusion limited current, it is found that effective rail resistance is proportional to the square root of the relative velocity, the permeability of the rail and the length between the armature and that effective skin depth of the rail is proportional to the square root of the length and inversely proportional to the square root of the permeability, the conductivity and the velocity.

• Geomechanics and Engineering
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• v.10 no.6
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• pp.737-755
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• 2016

The load transfer depth of a ground anchor is the minimum length required to transfer the initial prestressing to the grout column through the bonded part. A thorough understanding of the mechanism of load transfer as well as accurate prediction of the load transfer depth are essential for designing an anchorage that has an adequate factor of safety and satisfies implicit economic criteria. In the current research, experimental and numerical studies were conducted to investigate the load transfer mechanism of ground anchors based on a series of laboratory and field load tests. Optical FBG sensors embedded in the central king cable of a seven-wire strand were successfully employed to monitor the changes in tensile force and its distribution along the tendons. Moreover, results from laboratory and in-situ pullout tests were compared with those from equivalent case studies simulated using the finite difference method in the FLAC 3D program. All the results obtained from the two proposed methods were remarkably consistent with respect to the load increments. They were similar not only in trend but also in magnitude and showed more consistency at higher pullout loading stages, especially the final loading stage. Furthermore, the estimated load transfer depth demonstrated a pronounced dependency on the surrounding ground condition, being shorter in hard ground conditions and longer in weaker ones. Finally, considering the safety factor and cost-effective design, the required bonded length of a ground anchor was formulated in terms of the load transfer depth.

• The Korean Journal of Emergency Medical Services
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• v.23 no.2
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• pp.109-123
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• 2019

Purpose: This study aimed to propose an effective one-rescuer infant cardiopulmonary resuscitation (CPR) chest compression technique by comparing the differences in efficacy, convenience, and pain levels between the two thumb-encircling and two finger techniques. Methods: Subjects were randomized to perform either two-thumb-encircling or two-finger technique for 8 minutes each on infant CPR manikins. After the chest compression, a survey was administered to the subjects to measure convenience and pain levels according to compression method. Results: Total compression depth over 8 minutes was significantly deeper for the two-thum-encircling technique ($43.5{\pm}4.8mm$) compared with the two-finger technique ($32.6{\pm}5.4mm$) (p<0.001). In terms of compression depth measured at 1-minute intervals, compression depth with the two-finger technique decreased from $38.3{\pm}4.23mm$ to $29.0{\pm}6.79mm$, whereas compression depth with the two-thumb-encircling technique did not show a significant change (from $43.7{\pm}4.12mm$ to $43.4{\pm}5mm$). The results of the survey indicated that, the majority of subjects found the two-thumb-encircling technique to be the most comfortable technique for compression depth (n=29, 64.4%). The majority of subjects (n=31, 68.9%) answered that the two-finger technique resulted in the most pain. Conclusion: Comparison of efficacy of the two-thumb-encircling and two-finger-techniques in the performance of one-rescuer infant CPR revealed that the two-thumb-encircling technique was more effective in maintaining chest compression depth.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.6
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• pp.527-532
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• 2013

Depth estimation is an essential factor for robot vision, 3D scene modeling, and motion control. The depth estimation method is based on focusing values calculated in a series of images by a single camera at different distance between lens and object. In this paper, we proposed a relative depth estimation method using focus measure. The proposed method is implemented by focus value calculated for each image obtained at different lens position and then depth is finally estimated by considering relative distance of two patterns. We performed various experiments on the effective focus measures for depth estimation by using various patterns and their usefulness.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.9
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• pp.863-871
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• 2004

The use of fossil fuels like coal, oil and natural gases around the world causes an increase of the carbon dioxide content in the atmosphere. In order to reduce the concentration of the greenhouse gas, the idea of carbon dioxide sequestration in the ocean is proposed to be an effective mitigation strategy to counteract potential global warming due to the greenhouse effect. Therefore, in the present study, calculations of the dissolution behavior of carbon dioxide when liquid carbon dioxide is released at 1,000m and 1,500m in depth by fixed pipeline are performed. The results show that carbon dioxide droplets change to carbon dioxide bubbles in gas phase around 500m in depth, and the droplets are completely dissolved below 500 m in depth if the liquide carbon dioxide is released both at 1,000 m in depth with the initial diameter of 0.007m or less and at 1,500m in depth with the diameter of 0.011m or less.