• ETRI Journal
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• v.29 no.3
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• pp.270-280
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• 2007

In Linux, real-time tasks are supported by separating real-time task priorities from non-real-time task priorities. However, this separation of priority ranges may not be effective when real-time tasks make the system calls that are taken care of by the kernel threads. Thus, Linux is considered a soft real-time system. Moreover, kernel threads are configured to have static priorities for throughputs. The static assignment of priorities to kernel threads causes trouble for real-time tasks when real-time tasks require kernel threads to be invoked to handle the system calls because kernel threads do not discriminate between real-time and non-real-time tasks. We present a dynamic kernel thread scheduling mechanism with weighted average priority inheritance protocol (PIP), a variation of the PIP. The scheduling algorithm assigns proper priorities to kernel threads at runtime by monitoring the activities of user-level real-time tasks. Experimental results show that the algorithms can greatly improve the unexpected execution latency of real-time tasks.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.275-281
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• 2001

In the sheet metal forming process, the drawbead is used to control the flow of material during the forming process. The drawbead provides proper restraining force to the material and prevents defects such as wrinkling or breakage. For these reasons, many studies for designing the effective drawbead have been conducted. In this paper, the effect of the drawbead shape will be introduced. For the analysis, the numerical method called the static-explicit finite element method was used. The finite element analysis code for this method has been developed and applied to the drawbead process problems. In result, convergence problem and computation time due to large non-linearity in the existing numerical analysis methods were no longer a critial Problem. Futhermore, this approach could treat the contact friction problem easily by applying very small time intervals. It is expected that various results from the numerical analysis will give very useful information for the design of tools in sheet metal forming process.

• Journal of Periodontal and Implant Science
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• v.46 no.2
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• pp.128-134
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• 2016

Purpose: This article describes a case of the successful non-surgical management of a periodontally compromised maxillary premolar. Methods: A combination therapy, including root planing, occlusal adjustment, and tooth splinting, was applied. Clinical and radiographic examinations were performed during the 16-month follow-up period. Results: All periodontal parameters were improved. There were dramatic decreases (3-6 mm) in the probing pocket depth, tooth mobility, and marginal bone loss. Interestingly, gradual resolution of the periapical radiolucency and alveolar bone regeneration were observed in the radiographs, and the periodontal condition was maintained during the follow-up period. Conclusions: Within the limits of this study, these results demonstrate the importance of natural tooth preservation through proper periodontal treatment and occlusal adjustment of the periodontally compromised tooth, which is typically targeted for tooth extraction and dental implantation.

• Journal of the Korea Computer Industry Society
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• v.4 no.10
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• pp.695-702
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• 2003

It is necessary for us to have proper synchronization technology in order for continuous media and non-continuous media to be integrated and presented. In case of continuous media, it would be possible to convey significant information only after relevant synchronization is completed in the continuous media itself. In this thesis, I mentioned integration of these multi-media, basic notion of synchronization and synchronization technology. In order to process synchronization, I have researched into information used to fractionize methods regarding synchronization. And I have also discussed synchronization problems found in integration of continuous multi-media and through researching into case study of MHEG, I have analyzed how the synchronization of multi-media is processed and applied.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.76
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• pp.103-123
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• 2017

If additional condition in letter of credit is used in malicious way, it affects the international trade transaction in jeopardy. Therefore, it's significant to identify whether additional conditions are malicious or ordinary in the transaction with letter of credit. In normal cases, thanks to lots of useful features as an international payment method, such as security of payment, legal protection, and versatility, a letter of credit is widely used in international trade. However, even with these advantageous features, a letter of credit is complicate and costly to use, compared to other payment methods. Furthermore, due to its principle of independence from underlying contract, a use of letter of credit creates another type of concern for proper handling and needs significant caution upon field use. At some points, malicious additional conditions are used for buyer's advantage in deal making and fraud instance in worst situation. In addition, some countries request malicious conditions against sellers as a non-tariff barrier. Therefore it's extremely important to recognize whether malicious additional condition exists in letter of credit and, if so, how to deal with it. This study delivers the information to distinguish and categorize the malicious conditions in various cases and to figure out how to deal with them for safer trade with less risk.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.6 s.177
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• pp.1624-1632
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• 2000

In the sheet metal forming process, the drawbead is used to control the flow of material during the forming process. The drawbead provides proper restraining force to the material and prevents defe cts such as wrinkling or breakage. For these reasons, many studies for designing the effective drawbead have been conducted. In this paper, the effect of the drawbead shape will be introduced. For the analysis, the numerical method called the static-explicit finite element method was used. The finite element analysis code for this method has been developed and applied to the drawbead process problems. In result, convergence problem and computation time due to large non-linearity in the existing numerical analysis methods were no longer a critical problem. Futhermore, this approach could treat the contact friction problem easily by applying very small time intervals. It is expected that various results from the numerical analysis will give very useful information for the design of tools in sheet metal forming process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.1
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• pp.57-62
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• 2003

Machining technique for optical crystals with single point diamond turning tool is reported in tills paper. The main factors influencing the machined surface quality are discovered and regularities of machining process are drawn. Optical crystals have found more and more important applications in the field of modern optics. Optical crystals are mostly brittle materials of poor machinability The traditional machining method is polishing which has many shortcomings such as low production efficiency, poor ability to be automatically controlled and edge effect of the workpiece. SPDT has been widely used in manufacturing optical reflectors of non-ferrous metals such as aluminum and copper which are easy to be machined for their proper ductility. But optical crystals being discussed here are characterized by their high brittleness which makes it difficult to obtain high quality optical surfaces on them. The purpose of our research is to find the optimum machining conditions for ductile cutting of optical crystals and apply the SPDT technique to the manufacturing of ultra precision optical components of brittle materials. As a result, the cutting force is steady, the cutting force range is 0.05-0.08N. The surface roughness is good when spindle is above 1400rpm, and feed rate is small. The influence of depth of cut is very small.

• Journal of Chest Surgery
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• v.27 no.10
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• pp.850-853
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• 1994

Open lung biopsy was performed in thirty patients for the diagnosis and staging evaluation of interstitial lung disease during the period from January 1987 until December 1992. The age of the patients ranged from 14 to 71 years [mean 48 years], and the patients consisted of 14 males and 16 females. Preoperative FEV1`s were from 0.80 liter to 3.88 liters [mean 1.66]. Other non-invasive diagnostic studies such as PCNA, bronchoalveolar lavage, TBLB, and gallium scan were also done in addition to X-ray and high-resolution chest CT. Tweaty-eight were correctly diagnosed and 2 cases were not [diagnostic yield rate 93.3%]. Among the 28 cases,pathologic diagnosis influenced further treatment regimens and prognostic expectations in 23 cases [82.1%]. The diagnostic non-invasive studies other than open lung biopsy yielded a correct diagnosis without staging only in 5 cases. There was no mortality and only one complication, ARDS ; however, the patient recovered after 5 days ventilator support. Open lung biopsy, which is the gold standard for the diagnosis and staging evaluation of interstitial lung disease can be done safely and has value in clinical decision making. Also knowledge of the involvement of the lesion is important for proper selection of the biopsy site.

• Environmental Engineering Research
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• v.18 no.3
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• pp.145-150
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• 2013

Optimal preparation guidelines of a cathode catalyst layer by non-precious metal catalysts were evaluated based on electrochemical performance in single-chamber microbial fuel cells (MFCs). Experiments for catalyst loading rate revealed that iron(II) phthalocyanine (FePc) can be a promising alternative, comparable to platinum (Pt) and cobalt tetramethoxyphenylporphyrin (CoTMPP), including effects of substrate concentration. Results showed that using an optimal FePc loading of $1mg/cm^2$ was equivalent to a Pt loading of $0.35mg/cm^2$ on the basis of maximum power density. Given higher loading rates or substrate concentrations, FePc proved to be a better alternative for Pt than CoTMPP. Under the optimal loading rate, it was further revealed that 40 wt% of FePc to carbon support allowed for the best power generation. These results suggest that proper control of the non-precious metal catalyst layer and substrate concentration are highly interrelated, and reveal how those combinations promote the economic power generation of single-chamber MFCs.

• Journal of Astronomy and Space Sciences
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• v.12 no.1
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• pp.66-77
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• 1995

It is possible to distinguish X-ray events from non X-ray events in proportional conters using the method of rise time discrimination (RTD). In order to subtract non X-ray background, we have developed a simple RTD circuit which will be applied to the proportional counter planned for a sounding rocket experiment. The entire circuit consists of two parts ; the rise time measurement circuit and the time to amplitude conversion circuit which includes the self-calibration mode. From the test with X-ray detecting system, we obtained that the background can be rejected more than 80% in the energy band 2∼12 keV. However we confirmed that the RDT method is not proper to be used for the energy range above 12kV.