• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.23-30
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• 2006

Emulsified Asphalt Mixture(EAM) is more environmentally-friendly and cost-effective than typical Hot Mix Asphalt (HMA) because EAM does not produce carcinogenic substances, e.g., naphtha, kerosene, during the both of manufacturing and roadway construction process. Also, it does not require heating the aggregates and asphalt binder. However, EAM has some disadvantages. Generally EAM has a less load bearing capacity and more moisture susceptibility than conventional HMA. The study evaluated a Fiber modified EAM (FEAM) to increase load bearing capacity and to decrease moisture susceptibility of EAM. Modified Marshall mix design was developed to find Optimum Emulsion Contents (OEC), Optimum Water Contents (OWC), and Optimum Fiber Contents (OFC). A series of test were performed on the fabricated specimen with OBC, OWC, and OFC. Tests include Marshall Stability, Indirect Tensile Strength, and Resilient modulus test. Comparison analyses were performed among EAM, Fiber modified EAM (FEAM), and typical HMA to verify the applicability of EAM and FEAM in the field. Test results indicated that both of EAM and FEAM have an enough capability to resist medium traffic volume based on the Marshall mix design criteria. Also the study found that fiber modification is effective to increase the load bearing capacity and moisture damage resistance of EAM.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.05a
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• pp.34-39
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• 2002

The surfaces of machine components in sliding contact such as bearing, gears and pistons etc. frequently operate under the condition of mixed lubrication due to high load, high speed and slip. These machine components often undergo the inception of scuffing in practical application. The scuffing failure is a critical problem in modern machine components, especially for the requirement of high efficiency and small size. However, it is difficult to find a universal mechanism to explain all scuffing phenomena because there are so many factors affecting the onset of scuffing. In this study, scuffing experiments are conducted using Acoustic Emission(AE) measurement by an indirect sensing approach to detect scuffing failure. Acoustic Emission(AE) signal has been widely utilized to monitor the interaction at the friction interface. Using AE signals we can get an indication about the state of the friction processes, about the quality of solid and liquid layers eon the contacting surfaces in real time. The FFT(Fast Fourier Transform)analyses of the AE signal are used to understand the interfacial interaction and the relationship between the AE signal and the state of contact is presented

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2245-2253
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• 2018

With the increase of electrical consumption and the unbalance of power demand and supply, power reserve rate is getting smaller and also the reliability of the power supply is getting deteriorated. Under this circumstance, the electrical energy storage (EES) System is considered as one of essential countermeasure for demand side management. This paper proposes efficient evaluation algorithms of multiple functions for EES systems, especially the secondary battery energy storage systems, in the case where they are interconnected with the power distribution systems. It is important to perform the economic evaluation for the new energy storage systems in a quantitative manner, because they are very costly right now. In this paper, the multiple functions of EES systems such as load levelling, effective utilization of power distribution systems and uninterruptible power supply are classified, and then the quantitative evaluation methods for their functions are proposed. From the case studies, it is verified that EES systems installed at distribution systems in a dispersed manner have multiple functions involved with direct and indirect benefits and also they can be expected to introduce to distribution systems with respects to economical point of view.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.6 s.177
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• pp.1608-1615
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• 2000

The track tension is closely related to the maneuverability of tracked vehicles and the durability of tracks and suspension systems. In order to minimize the excessive load on the tracks and to pre vent the peal-off of tracks from the road wheels, it is required to maintain the optimum track tension throughout the maneuver. However, the track tension cannot be easily measured due to the limitation in the sensor technology, harsh environment, etc. In this paper an indirect track tension monitoring system is developed based on idler assembly models, a geometric relation around the idler, and the tractive force estimated by using the Extended Kalman Filter. The performance of the tension monitoring system is verified with the results obtained from the Multi-Body Dynamics model.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.6
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• pp.79-86
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• 2000

The effects of recirculated exhaust gas on the wears of piston and piston rings were investigated by the experiment with a two-cylinder, four cycle, indirect injection diesel engine operating at an engine load of 75% and an engine speed of 1600 rpm. For the purpose of comparison between the wear rates of two cylinders with and without EGR, the recirculated exhaust gas was sucked into one of two cylinders after the soot contenets in exhaust emissions were removed by an intentionally designed cylinder-type scrubber equipped with 6 water injectors(A water injector has 144 nozzles of 1.0 mm diameter), while only the fresh air was inhaled into the other cylinder. These experiments were carried out on the fuel injection timing fixed at 15.3$^{\circ}$ BTDC. It was found that the wear rate of piston skirt with EGR increased a little bit, but the piston head diameter increased, rather than decreased, owing to soot adhesion and erosion wear, and especially larger with EGR, and that the wear rates of the top and second piston ring(compression ring)thickness with EGR were more than twice the wear rate of top ring in case of no EGR, but the wear rate of oil rings thickness without EGR increased greater than that with EGR.

• Journal of Power Electronics
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• v.13 no.5
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• pp.806-813
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• 2013

This paper aims to compare the performance of three phase induction motor drives using Five Leg Inverter (FLI) and Three Leg Inverter (TLI) configurations. An Indirect Field Oriented Control (IFOC) method using a TLI is well established and incorporated for high performance speed drives in various industries. The FLI dual motor drive system on the other hand shows good workability in the independent control of two induction motor drives simultaneously. In this experiment, the IFOC method is utilized for both drive systems, and Space Vector Pulse Width Modulation (SVPWM) is used to generate pulses for both inverters. For the FLI, the Double Zero Sequence (DZS) Injection technique is used to generate the modulation signal. The complete experiment setup is done by using a DSpace 1103 controller board. The individual motor performances are analyzed using similar schemes, equipment setups and controller parameter values. The results show similar speed performance response capability between the single motor operation using a TLI system and the two motor operation using a FLI system based on the variable speed range either in forward or reverse operation. They also show similar load rejection abilities. However, the single motor with a TLI has a better power quality aspect such as ripple current and total harmonics distortion (THD).

• Journal of International Academy of Physical Therapy Research
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• v.1 no.2
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• pp.185-191
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• 2010

Background: This study investigated effective posture for gluteus medius rehabilitation training and effects of isometric muscle activity by electrophysiology through EMG while performing dynamic isotonic behavior of weight placed differently on upper limbs. Method: 16 healthy male subjects 20 to 29 years of age volunteered for the study. Lateral stabilizer right gluteus medius activity was assessed using EMG while the right lower extremity maintains single limb support, and the left upper extremity elevation movement maintains 5 seconds without load, 1RM to 1 repetition, 5RM to 5 times, 10RM to 10 times, 5RM and 10RM maintain 5sec. Results: Comparison of the mean value of EMG data showed a statistically more significant difference in upper extremity elevation movement on opposite upper extremity added weight than one that was not added on a single limb weight bearing posture(p>.05). Weight supported side gluteus medius activity for 1RM, 5RM, 10RM weight difference and movement repetition did not differ(p>.05). Comparison in maximum value showed statistically significant differences in not adding weight on upper limb elevation exercise and 1RM, 5RM, 10RM repeated behavior. Elevation behavior and repetition appeared over 70% of MVIC. Conclusion: Unilateral weight bearing stance added weight in the opposite upper limb elevation movement was an indirect exercise to effectively stimulate gluteus medius activity. Applying various added weight will have effective exercise on the early stages of rehabilitation because activity gluteus medius did not differ through added weight.

• Tribology and Lubricants
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• v.25 no.3
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• pp.163-170
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• 2009

We developed a compact micro indentation testing device (designated SNUT) which is capable to measure Young's modulus of a sample using depth and applied load data during indentation. Performance of this device was evaluated using pure Ti, pure Ni, and die steel (SKD11). As a result of analysing the indentation test data, the frame compliance $C_f$ was found to influence mainly the modulus by 80% among several factors affecting accuracy of Young's modulus. Project area, which was determined by indirect indentation method, was modified using direct SEM observation. Finally, Young's modulus error was reduced to 5% after taking into consideration the frame compliance and modified projected area from 80% error without any these two correction factors. The performance of SNUT and MTS instruments was compared using same specimen (pure Ti).

• Tribology and Lubricants
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• v.18 no.5
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• pp.351-356
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• 2002

The surfaces of machine components in sliding contact such as bearing, gears and pistons etc. frequently operate under the condition of mixed lubrication due to high load, high speed and slip. These machine components often undergo the inception of scuffing in practical application. The scuffing failure is a critical problem in modern machine components, especially for the requirement of high efficiency and small size. However, it is difficult to find a universal mechanism to explain all scuffing phenomena because there are so many factors affecting the onset of scuffing. In this study, scuffing experiments are conducted using Acoustic Emission(AE) measurement by an indirect sensing approach to detect scuffing failure. Acoustic Emission(AE) signal has been widely utilized to monitor the interaction at the friction interface. Using AE signals we can get an indication about the state of the friction processes, about the quality of solid and liquid layers on the contacting surfaces in real time. The FFT(Fast Fourier Transform) analyses of the AE signal are sued to understand the interfacial interaction and the relationship between the AE signal and the state of contact is presented.

• Special Issue of the Society of Naval Architects of Korea
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• 2008.09a
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• pp.68-75
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• 2008

This paper describes the design and implementation of a low cost inertial navigation system(INS) using an inertial measurement unit(IMU), a digital compass, GPS, and an embedded system. The system has been developed for a transporter that load and unload ship blocks in a shipbuilding yard. When the transporter would move from place to place, they would periodically pass under obstructions that would obscure the GPS signal. This increases the error when estimating the position. Thus the INS has been used to improve position accuracy. INS is also capable of providing continuous estimates of the transporter's position and orientation. Even though IMU is typically very expensive, this INS is made of "low cost" components and the indirect Kalman filtering algorithm.