• Special Issue of the Society of Naval Architects of Korea
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• 2008.09a
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• pp.133-135
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• 2008

For complying with the increasing number of ships construction, it's required that not only for minimizing the period of construction in Skid Berth also maximizing application proportion of Skid Barge, The full-ship load out construction method required indispensably.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.79-85
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• 2023

Skid resistance pavement is an accessory to the road and is a facility for the safe driving of cars by increasing the skid resistance of road pavement. In particular, in bad weather conditions such as snow, rain, and black ice, the skid resistance performance of skid resistance pavement greatly affects the safety of road traffic and drivers. However, BPT(British Pendulum Tester) has a test area of only 0.009 m², making it difficult to represent the overall packaging surface. A reliable method of evaluating slip resistance performance is needed for maintaining non-slip packaging. In this study, the conventional BPT test and the skid resistance performance evaluation method of the PFT(Pavement Friction Tester) and µGT(Micro Grip Tester) tests were compared through guidelines and standard investigations and applied to the field skid resistance performance evaluation. In addition, skid resistance pavement with different skid resistance performance was installed at the test-bed and actual road demonstration sites to compare BPN(British Pendulum Number), SN(Skid Number), GN(Grip Number), and to derive correlations for each performance evaluation method. As a result of the experiment, SN and GN showed similar skid resistance performance, and the GN value was derived similar to BPN × 0.01.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.2
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• pp.79-85
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• 2007

The skid-steering method that applied a number of mobile robot currently is very effective in narrow area. But it contains several problems of its natural properties, slip, occurred by different direction between vehicle's driving and wheel's rotary. From this thesis we want to suggest suitable structure of $6{\times}6$ skid steering wheeled vehicle and method of driving by analyzing the behavior of $6{\times}6$ skid-steered wheeled vehicle by engineering analytical method

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.4
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• pp.71-82
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• 2020

Traffic accidents due to excessive speed frequently occur in places where traffic signal controllers are installed, places where sharp curves exist, or places where the traffic signal cycle does not match the current time. These traffic accidents cause economic loss due to the destruction of road facilities and structures, and cause a big problem of increasing the number of traffic accident deaths. When a traffic accident occurs, leaving a tire mark before or after a car crash, pre-collision speed of the car is calculated using the law of conservation of momentum or the skid mark formula. In the skip skid mark generated in ABS brake vehicles and the combshaped yaw mark generated by tire trace caused by lateral sliding, there is a difference of 30-40% in the reliability of the vehicle speed calculated by the smite mark. In this paper, we propose an algorithm that can improve the calculation reliability in vehicle speed by using skid marks in order to compensate for this problem. In addition, we present an intelligent speed calculation algorithm for traffic safety and a computer simulation in order to prevent traffic accidents by estimating the speed of a vehicle, using Skid marks, Yaw marks, and ABS brake characteristics and fuzzy rules.

• Journal of Korean Society of Forest Science
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• v.108 no.4
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• pp.582-591
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• 2019

This study was conducted to develop low-cost, simplified slope stabilization methods for the continuous utilization of skid trails, and to analyze the effect of the developed methods. Slope stabilization methods were created on the fill slopes of skid trails in the Forest Technology and Management Research Center of the National Institute of Forest Science.We measured the settlement and bearing capacity of skid trail surfaces, and the displacement of slope stabilization methods with respect to the number of passes (maximum 100 passes) by a logging truck weighing 17 tons. The constancy of slope stabilization methods was determined by measuring displacement of the stabilization structure with respect to the number of logging truck passes. Results showed that the bearing capacity in most cases was insufficient, but that the settlement of skid trails was less than 150 mm, which was considered reasonable. In addition, the stability of root staking wallswas somewhat low, but the average displacements of all slope stabilization methods were generally around 20 mm or less, indicating no issues regarding structural stability. By applying the simplified stabilization methods to skid trail maintenance following timber harvesting, efficient timber harvesting can be achieved. Additionally, these methods can be utilized as permanent forest management infrastructures and complement insufficient forest road facilities.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.3
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• pp.231-238
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• 2002

In this paper, we present a new approach to autopilot design for skid-to-turn missiles which may have severe aerodynamic cross-couplings and nonlinearities with angle of attack. The model of missile motion is derived in the maneuver plane and, based on that model, pitch, yaw, and roll autopilot are designed. They are composed of a nonlinear term which compensates for the aerodynamic couplings and nonlinearities and a linear controller driven by the measured outputs of missile accelerations and angular rates. Besides the outputs, further information such as Mach number, dynamic pressure, total angle of attack, and bank angle is required. With the proposed autopilot and simple estimators of bank angle and total angle of attack, it is shown by computer simulations that the induced moments and some aerodynamic nonlinearities are properly compensated and that the performance is superior to that of the conventional ones.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.2
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• pp.1-11
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• 2011

The skid-steering method that applied a number of mobile robot currently is extremely effective in narrow area. But it contains several problems such as its natural properties, slip, occurred by different direction between vehicle's driving and wheel's rotary. Through this paper, suitable control algorithm of $6{\times}6$ skid steering wheeled vehicle and its driving methods are proposed by analyzing the behavior $6{\times}6$ skid-steered wheeled vehicle model designed by engineering analysis strategy. To do this, based on a behavior of designed driving system, required torque and other performance of in-wheel type motor system are considered, and finally control algorithm for each wheel is proposed and simulated using this model. To test the proposed vehicle system, driver model is designed using PID closed loop system and included in the total driving control algorithm. The Performance of designed vehicle model is verified by using DYC (Direct Yaw Control) cornering mode and slip mode control to follow the steering input which are essential to evaluate the driving performance of $6{\times}6$ vehicle. Proposed modeling strategy and control method will be implemented to the real $6{\times}6$ in-wheel drive type vehicle.

• Journal of the Korea Society of Computer and Information
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• v.27 no.12
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• pp.277-284
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• 2022

In this paper, we proposes a method of optimizing the processing order of skids to minimize the span time in a conveyor environment of the shipbuilding subassembly process. The subassembly process consists of a series of fixed tasks where the required work time is varied according to the skid type. The loading order of skids on a conveyor which determines the span time should be properly optimized and the problem size exponentially increases with the number of skids. In this regard, we propose a novel method called UniDev by defining a measure of the mean-absolute-deviation about the time difference among simultaneously processed tasks and iteratively improving it. Through simulations with various numbers of skids and processes, it was observed that our proposed method can efficiently reduce the overall work time compared with the multi-start and the 2-OPT methods.

• International Journal of Highway Engineering
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• v.14 no.6
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• pp.45-55
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• 2012

PURPOSES : Skid resistance and noise of roads highly depend on the characteristics of pavement texture. Therefore, estimation of texture characteristics may give useful information for the skid resistance and noise of road. Generally, Sand Patch Test is performed in order to estimate MTD(Mean Texture Depth). However, it is time-consuming and needs traffic control. This study aimed to investigate the effectiveness of measurement texture depth using the Portable Laser Profiler that give the MPD(Mean Profile Depth). METHODS : MTD and MPD were collected on the number of expressway sections including Central Inland Test Road sections in Korea. Statistical analysis are performed to establish the relationship between MTD data based on Sand Patch Test and MPD data obtained by the Portable Laser Profiler. RESULTS : Linear relationship MPD and MTD is observed for both of asphalt pavement and concrete pavement such as R-square of 0.51 to 0.58. CONCLUSIONS : Even though, the test method and definition of MPD and MTD are different. EMTD(Estimated Mean Texture Depth) can be obtained by using the correlationship between MPD with MTD.

• International Journal of Highway Engineering
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• v.16 no.1
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• pp.31-39
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• 2014

PURPOSES : Surface treatment material for pavement preventive maintenance should be inspected field applicability. This study(Part II) aimed to checkup coating characteristics and performance analysis using lab and field tests. The hydrophobic - low viscosity filling material for pavement preventive maintenance is presented in Part I, which is a series of companion study. METHODS : Relative comparison between general asphalt mixtures and surface treatment asphalt mixtures are analyzed and measured for the field application such as indirect tensile strength ratio(TSR), abrasion resistance, crack propagation resistance, temperature resistance, coating thickness, permeability resistance and skid resistance in terms of british pendulum number(BPN). RESULTS : It is found that TSR, crack propagation resistance and permeability resistance is increased as against uncoated asphalt specimen. Abrasion resistance and temperature resistance is secured from the initial coating thickness point of view, which is about 0.2~0.3mm. Skid resistance on the surface treatment pavement is satisfied with the BPN criteria of national highway because of exposed aggregate and crack sill induced pavement deterioration and damage cracks. CONCLUSIONS : The hydrophobic - low viscosity surface treatment material for pavement preventive maintenance is validated on field applicability evaluation based on quantitative analysis of coating thickness and performance analysis using lab and field tests.