• Journal of the Korean Society for Precision Engineering
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• 제15권11호
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• pp.9-20
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• 1998

In recent manufacturing process, the increase of productivity has been attempted by reducing machining time with the increase of cutting force. However, the excessive increase of cutting force can cause tool breakage and have a bad effect on both manufacturing machine and workpiece. Thus, it is necessary to estimate and control the cutting force in real time during the process. In this study, use of disturbance observer is proposed for the indirect cutting force estimation. The estimated cutting force is used for the real-time control of feedrate, making the actual cutting force follow the reference force command. Since the suggested method does not need an expensive sensor like a dynamometer, the method is expected to be used practically. Since the actual cutting force follow the reference force, resulting the reducing of the machining time the increase of productivity are also expected, and the quality of cutting surface has been improved due to the adjusted feedrate. Besides, an actual constant cutting force guarantees the prevention of tool breakage. To show the effectiveness of the suggested cutting force control method, an experimental setup has been made without sensor and applied to several workpieces. Experiments show that the suggested method is effective to cutting force control of a CNC machining center.

• Journal of the Korean Geotechnical Society
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• 제24권1호
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• pp.5-13
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• 2008

The coefficient of permeability for a soil can be determined by the direct or the indirect method. The direct method of permeability can be performed either in the laboratory or in the field. The indirect method can be predicted from the soil-water characteristic curve. In this study, the coefficient of permeability for an unsaturated soil was determined by the modified apparatus of steady-state method (Klute, 1972) and was predicted from the equations of Brooks & Corey (1964) and van Genuchten (1980). The experimental results were compared with predicted coefficient of permeability and the applicability of the two equations (from Brooks & Corey, van Genuchten) was reviewed.

• International Journal of Highway Engineering
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• 제12권4호
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• pp.203-209
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• 2010

The base asphalt mixtures that used the waste recycle asphalt correcting from the four different overlay construction sites in Seoul city were made using the foamed asphalt method. The sample mixtures were made in different ratio of the recycle asphalt and new asphalt material and the performance of the mixtures of the different ratio was investigated in the laboratory. The laboratory tests includes the Marshall test, the indirect tensile test, the resilient modulus test, the creep test and the wheel tracking test. The test of the recycle foamed asphalt mixtures(RFA) were compared with the those of the recycle hot mix asphalt(RHA) mixtures. The performance of the RFA is comparable to that of the RHA. On the other hand, the indirect tensile strength of the RFA in dry condition is lower than that of RHA and the indirect tensile strength of the RFA in wet condition is much lower than that of the RHA.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3387-3390
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• 2013

Catalytic gasification of mandarin waste residue was carried out using direct and indirect catalyst-contact methods for the first time. In the indirect method, non-catalytic reaction in a reactor was followed by catalytic upgrading of vapor product in another reactor. Two different catalysts, $Ni/{\gamma}-Al_2O_3$ and $Ni/CeO_2-ZrO_2$, were employed. $CeO_2-ZrO_2$ support was prepared using hydrothermal synthesis in supercritical water. The catalysts were characterized by $H_2$-temperature programmed reduction and Brunauer-Emmett-Teller analyses. Under the condition of equivalent ratio (ER) = 0, the indirect catalyst-contact method led to a higher gas yield than the direct method. Under ER = 0.2, the yield of biogas obtained over $Ni/CeO_2-ZrO_2$ was higher than that obtained over $Ni/{\gamma}-Al_2O_3$. Also, the coke formation of $Ni/CeO_2-ZrO_2$ was lower than that of $Ni/{\gamma}-Al_2O_3$. Such results were attributed to the higher reducibility and better lattice oxygen mobility of $Ni/CeO_2-ZrO_2$, which were advantageous for partial oxidation reaction.

• Journal of Korea Technology Innovation Society
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• 제14권spc호
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• pp.1152-1170
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• 2011

We selected core documents from enormous number of documents by analyzing citation relation of papers or patents including direct citation and indirect citation. Then we tried to creat the technology evolution path from citation network tree. By applying the method to the patent DB of OLED (Organic Light Emitting Diode), we obtained genealogical citation network of core patents of OLED. We analyzed how the one of OLED technology was transferred to the semiconductor related technology and we named the process of transition as 'technology evolution path' of OLED technology. And we also analyzed the genealogical citation network of papers on graphene. From the analysis, we found that the weight count method including indirect citation was better in evaluating the value of technology of a paper than the times cited method.

• Proceedings of the KSR Conference
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.444-449
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• 2003

This paper presents a vector control method for the parallel-connected motor drive system. In this paper new estimation scheme of rotor flux position is presented to reduce sensitivity due to load difference between the motors. To confirm the validity of the proposed control method, we compare a simulation result of the proposed control method with that of the conventional indirect vector control method. The simulation results show that the proposed control method is effective the step change in load torque.

• Proceedings of the KIEE Conference
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.649-652
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• 2003

In this paper, we presents a vector control method for the parallel-connected motor drive system. The new estimation scheme of rotor flux position is presented to reduce sensitivity due to load difference between the motors. To confirm the validity of the proposed control method. we compare a simulation result of the proposed control method with that of the conventional indirect vector control method. The simulation results show that the proposed control method is more effective for change in load torque and motor parameters.

• Journal of Korean Academy of Nursing Administration
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• 제5권2호
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• pp.389-400
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• 1999

The purpose of this study is to examine a possibility of applying the ABC system to analyze the cost of nursing service on one obstetrics and gynecology (OB/GYN) unit in a major medical center. The activities of nurses on an OB/GYN unit were analyzed for 4 days for 96 hours. 2 week days and 2 days on weekend. Total cases included in the study were activities of 12 charge nurses and 12 staff nurses. Activities were categorized into direct and indirect activities in order to calculate the cost of activities. Nursing activities were defined multidimesionally in order to utilize the ABC system. The 60 nursing activities were classified into the direct nursing activities and the indirect nursing activities based on a literature review, interview, and survey results. The direct activities were further categorized into the single nursing activities and the multiple nursing activities. The indirect activities were classified into the indirect nursing service activities and the general management activities. The major findings of this study were as follows : 1. There were differences in activities according to the positions and duties of the nurses. The charge nurses mostly performed the indirect nursing service activities and the general management activities. Almost all of their indirect nursing activities spent on each patient were similar. The staff nurses performed the single nursing activities and the multiple nursing activities. 2. The activities of staff nurses included medication, patient assessment, rounding and organizing the unit. patient education, nursing treatment, admission and discharging of patients. There was no differences in types and amount of time spent between the nurses on day-time duty and evening-time duty, but the patient assessment activity increased during the night-time. 3. The cost of post partum nursing services for women who had a normal vaginal delivery using the ABC system included the cost incurred by direct nursing activities provided by the staff nurses (85.9%), indirect nursing activities incurred by the staff nurses(19.0%) and the nursing activities by the charge nurses and the head nurse(14.1%). The ABC system is a relatively new method of cost analysis. The results of this study can provide the nursing and hospital managers with useful information on cost control. It is suggested that more studies should be done using the ABC system and extend the scope of studies to include value analysis to aid the Activity-Based Management(ABM) and/or the reengineering of hospital process.

• The Journal of Korean Academy of Prosthodontics
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• 제45권5호
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• pp.611-620
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• 2007

Statement of problem: Second-generation indirect composite resins have been improved flexural strength, compressive strength, hydrolytic degradation resistance, wear resistance compared to first-generation indirect composite resins, but there are still some problems as hydrolysis and low wear resistance. Some manufacturers claim that wear resistance of their materials has been improved, but little independent study has been published on wear properties of these materials and the properties specified in the advertising materials are largely derived from in-house or contracted testing. Purpose: This study was to evaluate the wear of indirect composite resins (SR Adore, Sinfony, Tescera ATL) and gold alloy against the human enamel. Material and method: Extracted human incisors and premolars were sectioned to $2{\times}2{\times}2mm$ cube and embedded in the clear resin and formed conical shaped antagonist to fit the jig of pin-on-disk tribometer. Total 20 antagonists were stored in distilled water. Five disk samples, 24mm in diameter and 1.5mm thick, were made for each of three groups of indirect composite resins and gold alloy group, and polished to #2,000 SiC paper on auto-polishing machine. Disk specimens were tested for wear against enamel antagonists. Wear test were conducted in distilled water using a pin-on-disk tribometer under condition (sliding speed 200rpm contact load 24N, sliding distance 160m). The wear of the enamel was determined by weighing the enamel antagonist before and after test, and the weight was converted to volumes by average density. The wear tracks were analyzed by scanning electron microscopy and surface profilometer to elucidate the wear mechanisms. Statistical analysis of the enamel wear volume, wear track depth and wear tract width of disk specimens were accomplished with one-way ANOVA and the means were compared for significant differences with Scheffe's test. Results: 1. The enamel wear was most in gold alloy, but there were no statistically significant differences among all the groups (P>.05). 2. In indirect composite resin groups, the group to make the most shallow depth of wear tract was Sinfony, followed by Tescera ATL, SR Adoro (P<.05). Gold alloy was shallower than Sinfony, but there was no statistically significant difference between Sinfony and gold alloy (P>.05). 3. The width of wear tract of SR Adore was larger than the other groups (P<.05), and there were no statistically significant differences among the other groups (P>.05). 4. SEM analysis revealed that Sinfony and gold alloy showed less wear scars after test, Tescera ATL showed more wear scars and SR Adore showed the most. Conclusion: Within the limits of this study, Sinfony and gold alloy showed the least wear rates and showed similar wear patterns.

• Journal of Acupuncture Research
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• 제17권4호
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• pp.160-171
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• 2000

Thirty cases were observed among the peripheral facial paralysis patients who admitted. the Department of Acupuncture and Moxibustion of Seoul Oriental Hospital between Feb. 2nd, 1995 and Aug. 14th, 2000. These patients were divided into two groups; the first group was treated with indirect facial moxibustion., while the second with basic oriental-westem medicine treatment. Object : To improve the therapeutic rate of peripheral facial paralysis by applying basic oriental-western medicine treatment and indirect facial moxibustion. Method : Inpatients suffering from peripheral paralysis of facial nerve were divided into two groups; both groups recieved basic oriental-western medicine treatment; the experimental group additionally received indirect facial moxibustion onto Tuyu(頭維) and Chich'ang(地倉) once or twice daily. Result : In the therapeutic result from moxibustion treatment group, 3 excellent, 7 good, 3 fair, and 1 poor case were observed. From compound treatment group, 2 excellent, 5 good, 5 fair and 4 poor cases were observed. Among the excellent and good patients of both groups, therapeutic rate of moxibustion treatment group (71.4%) was higher than that of compound treatment group(43.8%). Conclusion : The overall therapeuric rate of the moxibustion treatment group was 92.8%, which was higher than that of the compound treatment group(75.1%).