• Journal of the Korean Institute of Gas
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• v.19 no.1
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• pp.12-17
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• 2015

The core of the CNG fueling station is the compressor and most of CNG compressors in Korea require lubrication. Lubrication oil of CNG compressor that can be transferred into the pressure regulators and the engines of fueling system can cause a negative effect on NGV(Nature Gas Vehicle) performance during refueling due to oil Carry-over. In order to avoid the problem, it is necessary to enhance the quality of the compressed natural gas by measuring quantitatively the amount of the transferred oil. In this research, a sampling device and sampling tube were developed, which can be used with a gravimetric method of detection to measure CNG oil Carry-over. In addition, CNG samples were taken at 6 pre-selected CNG fueling stations and analysed for their trace oil Carry-over. The measured total oil Carry-over ranged from 2.569 to 6.509 ppm. This test measurements were compared with those of previous studies to verify the results.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.1
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• pp.21-33
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• 2007

Statement of problem: The esthetic component of dental care has become increasingly more important, while new tooth-colored materials are continually marketed. Various new indirect composite materials have been developed with required advantages. The most recent development in the indirect composites has been the introduction of the second-generation laboratory composite or poly-glass materials. They are processed by different laboratory techniques based on combinations of heat, pressure, vacuum and light polymerization. Although, second generation products became available in 1995, their characteristics and clinical performance have not been adequately investigated. Purpose: The aim of this study was to measure the mechanical properties of the second generation indirect resin system and compare these with an existing universal direct composite resin. Material and method: In this study four indirect composite material (Adoro LC, BelleGlass HP, Tescera, Synfony) were tested for flexural strength, wear resistance, hardness and their degree of conversion against Z250, a light cure direct composite. Results: Within the limitations of this study, the following conclusions were drawn: 1. From the abrasion wear result, Adoro showed the least volume loss while Synfony showed the greatest volume loss. Z250 and BelleGlass HP didn't show significant difference (p>0.05), but they showed significant difference with other groups (p<0.05). From the attrition wear, BelleGlass HP showed the least volume loss and it didn’t show significant difference with Tescera (p>0.05). While Synfony showed the greatest volume loss that it showed significant difference with other groups (p>0.05). 2. Mean values of flexural strength by means of three point bending test was in the order of Z250, Adoro, Belleglass HP, Tescera and Synfony. Mean elastic modulus was in the order of Z250, BelleGlass HP, Tescera, Adoro and Synfony. 3. The result of Vicker‘s microhardness value showed that significantly higher value in Z250 (p<0.05), and is in the order of BelleGlass HP, Tescera, Adoro and Synfony. 4. The degree of conversion measured by FT-IR showed significantly higher value in BelleGlass HP (p<0.05), and is in the order of Adoro, Synfony, Tescera and Z250. Conclusion: Significant differences were found in the flexural strength, wear resistance, hardness and their degree of conversion.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.12 no.2
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• pp.21-25
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• 2006

Objective: The purposes of this study are to provide fundamental data and a rehabilitation program in physical therapy. It has been operated by 30 male college students for lumbar isokinetic exercises. Method : Subjects have been carried out in an experiment by Biodex system operating isokinetic torso rotation. This performance was activated by left rotation after right rotation repeatedly. Results: 1. The mean peak torques at $60^{\circ}$/sec were $95.6{\pm}20.62$ (Rt) and $93.84{\pm}18.41$ (Lt). 2. The mean peak torques/body weight at $60^{\circ}$/sec were $69.28{\pm}28.31$ (Rt) and $67.07{\pm}27.04$ (Lt). 3. The total works in right side at $60^{\circ}$/sec and $180^{\circ}$/sec were $492.21{\pm}92.37$, $1294.97{\pm}278.96$ and in left side at $60^{\circ}$/sec and $180^{\circ}$/sec were $515.78{\pm}109.47$, $1443.74{\pm}329.67$. 4. The work to body weight ratio at $60^{\circ}$/sec was $78.30{\pm}32.37$ (Rt) and $79.93{\pm}37.30$ (Lt). 5. The average powers in right side at $60^{\circ}$/sec and $180^{\circ}$/sec were $76.75{\pm}16.69$, $117.19{\pm}29.94$ and in left side at $60^{\circ}$/sec and $180^{\circ}$/sec were $78.54{\pm}18.58$, $125.39{\pm}32.90$. 6. The work fatigue at $180^{\circ}$/sec was $21.76{\pm}14.82$ (Rt) and $19.66{\pm}26.23$ (Lt). Conclusion: In right side and left side, there was no significant difference in peak torque. peak torque/body weight, work to body-weight ratio, average power of trunk rotators at $60^{\circ}$/sec(p<0.05). However there was a significant difference in the total work of trunk rotators at $60^{\circ}$/sec(p>0.05). Also there was a significant difference in the average of trunk rotators at $180^{\circ}$/sec(p>0.05).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.31-37
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• 2016

Ranging is divided into a synchronous scheme and an asynchronous scheme according to the presence of global synchronization between nodes. In general, the asynchronous ranging is preferred over synchronous ranging because it does not require an expensive high-precision oscillator for the global synchronization. On the other hand, in a conventional asynchronous ranging scheme, the packets, which are generated by all nodes in a positioning system of a large-scale infrastructure and need to be sent for localization by reference nodes, are considerable, which cause an increase in network traffic as the number of nodes increases. The traffic congestion lowers the throughput of the network leading to a considerable loss of energy. To solve this problem, this paper proposes a ranging scheme, in which virtual transmission slots randomly and discretely selected by a plurality of nodes are used to reduce the overheads needed in synchronizing the nodes, and the ranging is performed asynchronously based on the virtual transmission slots, thereby decreasing the network traffic. In addition, a performance test proved that the proposed ranging scheme was stronger than the TWR and SDS-TWR on an error range, even though the intensity of traffic was very low.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2C
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• pp.246-253
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• 2010

In this paper, a method of removing the space skew and cross-talk cancellation is proposed where the self-generated signals from the subject are used to obtain the subject's location. In the proposed method, the good spatial sound image is maintained even when the listener moves from the sweet spot. Two major parts of the proposed method are as follows: listener position tracking using the stimuli from the subject and removal of the space skew and cross-talk signals. Listener position tracking is achieved by estimation of the time difference of arrival (TDoA). The position of the listener is then computed using the Talyer-series estimation method. The head-related transfer functions (HRTF) are used to remove the space skew and cross-talk signals, where the direction of the HRTF is given by the one estimated from the listener position tracking. The performance evaluation is carried out on the signals from the 100 subjects that are composed of the 50 female and 50 male subjects. The positioning accuracy is achieved by 70%~90%, under the condition that the mean squared positioning error is less than $0.07m^2$. The subjective listening test is also conducted where the 27 out of the 30 subjects are participated. According to the results, 70% of the subjects indicates that the overall quality of the reproduced sound from the proposed method are improved, regardless of the subject's position.

• Journal of KIISE:Databases
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• v.35 no.6
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• pp.505-517
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• 2008

This paper proposes a rewriting algorithm of OWL-DL ontology query in SPARQL. Currently, to obtain inference results of given SPARQL queries, Web ontology repositories construct inference ontology models and match the SPARQL queries with the models. However, an inference model requires much larger space than its original base model, and reusability of the model is not available for other inferrable SPARQL queries. Therefore, the aforementioned approach is not suitable for large scale SPARQL query processing. To resolve tills issue, this paper proposes a novel SPARQL query rewriting algorithm that can obtain results by rewriting SPARQL queries and accomplishing query operations against the base ontology model. To achieve this goal, we first define OWL-DL inference rules and apply them on rewriting graph pattern in queries. The paper categorizes the inference rules and discusses on how these rules affect the query rewriting. To show the advantages of our proposal, a prototype system based on lena is implemented. For comparative evaluation, we conduct an experiment with a set of test queries and compare of our proposal with the previous approach. The evaluation result showed the proposed algorithm supports an improved performance in efficiency of the inferrable SPARQL query processing without loss of completeness and soundness.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.1
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• pp.45-52
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• 2015

Fiber-reinforced polymer (FRP) has been generally accepted by civil engineers as an alternative for steel reinforcing bars (rebar) due to its advantageous specific tensile strength and non-corrosiveness. Even though some glass fiber reinforced polymer (GFRP) rebars are available on a market, GFRP is still somewhat uncompetitive over steel rebar due to their high cost and relatively low elastic modulus, and brittle failure characteristic. If the price of component materials of GFRP rebar is not reduced, it would be another solution to increase the performance of each material to the highest degree. The tensile strength generally decreases with increasing diameter of FRP rebar. One of the reasons is that only fibers except for fibers in center resist the external force due to the lack of force transfer and the deformation of only outer fibers by gripping system. Eliminating fibers in the center, which do not play an aimed role fully, are helpful to reduce the price and finally FRP rebar would be optimized over the price. In this study, the effect of the hollow section in a cross-section of a GFRP rebar was investigated. A GFRP rebar with 19 mm diameter was selected and an analysis was performed for the tensile test results. Parameter was the ratio of hollow section over solid cross-section. Four kinds of hollow sections were planned. A total of 27 specimens, six specimens for each hollow section and three specimens with a solid cross-section were manufactured and tested. The change by the ratio of hollow section over solid cross-section was analyzed and an optimized cross-section design was proposed.

• Korean Journal of Psychosomatic Medicine
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• v.15 no.2
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• pp.73-80
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• 2007

Anumber of prior studies have reported eye movement dysfunction in patients with dementia. The eye movement test which is non-invasive can evaluate the local brain function quantitatively. Therefore, it can be a useful method for characterizing regional brain abnormalities of patients with dementia. The aim of this paper is to review the literatures on eye movement abnormalities in dementia patients. Saccade system dysfunctions in Alzheimer disease include increased latency, reduced accuracy, and increased antisaccade error rates. Patients with frontotemporal dementia showed impaired reflexive saccade inhibition and increased latency and errors of antisaccade task. And delayed initiation of voluntary saccades, slow saccades, and increased errors and latency on antisaccade task were found in Huntington's disease. Patients with Parkinson’s disease dementia and dementia with Lewy bodies have characteristics of impaired in both reflexive saccade execution and complex saccade performance. However, there were few reports of abnormal eye movements in Creutzfeldt-Jakob disease; they could be found at the later stages after symptoms of dementia came to be evident, and secondary to cerebellar and vestibular involvement. Slowing of saccades and hypometric saccades might precede the supranuclear limitation of vertical gaze in PSP. Dysfunction of voluntary eyelid movements was a characteristic finding of PSP as well. In conclusion, patients with dementia can show various abnormal eye movements and they are related with cortial and subcortical brain dysfunctions. The research on localization of brain relevant to each symptom can promise more clinical implications of eye movement of dementia.

• Journal of the Korean Society for information Management
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• v.32 no.2
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• pp.131-152
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• 2015

This study described the results of converting RDB to RDF ontology by each of R2RML method and Non-R2RML method. This study measured the size of the converted data, the conversion time per each tuple, and the response speed to queries. The STNet, a structured terminology dictionary based on RDB, was served as a test bed for converting to RDF ontology. As a result of the converted data size, Non-R2RML method appeared to be superior to R2RML method on the number of converted triples, including its expressive diversity. For the conversion time per each tuple, Non-R2RML was a little bit more faster than R2RML, but, for the response speed to queries, both methods showed similar response speed and stable performance since more than 300 numbers of queries. On comprehensive examination it is evaluated that Non-R2RML is the more appropriate to convert the dynamic RDB system, such as the STNet in which new data are steadily accumulated, data transformation very often occurred, and relationships between data continuously changed.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.472-479
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• 2000

A persimmon harvesting vehicle that can be operated in hilly orchards as well as a manipulator that can be used to harvest persimmons located in remote positions in the trees were designed and developed. The vehicle could be operated with keeping balanced position in an inclined field and its working platform could be moved up and down easy to approach fruits in a remote region with the aids of a hydraulic and a electrical and electronics systems. The weight of the vehicle was 927 kg and the center of gravity was located at 427 mm to the inner side from the center of a right driving caterpillar, 607 mm to a rear axle from the center of a front axle, and 562 mm to upward from ground. The automatic level control sensor for leveling the working platform was activated within 14.5 ∼ 16.5 degrees of slope variation. The total length of the manipulator was 1.39 m and weight is 975 g. It was powered by a 12 V geared motor to detach persimmon fruits with a rotational force. The gripper was made of plastic and rubber to increase a frictional force. In a performance evaluation test, static tipping angle, dynamic tipping angle toward front side when the vehicle was moving downward, climbing angle, driving speed of the vehicle were measured or calculated. In persimmon harvesting tests 24.9% of yield was increased by hand picking with the aid of the vehicle and additional 7% of yield were increased when the manipulator was used. Therefore, 99010 of total possible yield was achievable when both of the vehicle and the manipulator were used for the manual persimmon harvesting. Increase in 22.5% of total yield was achieved with the manipulator only.