• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.235-242
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• 2000

The purpose of this in vitro study was to evaluate the sealing ability of three sealers(Sealapex, Pulp canal sealer, AH26) used with continuous wave method using an anaerobic bacterial leakage model. 53 extracted human teeth with straight and single canals were prepared with crown-down pressureless technique using .04, .06 taper Profile(Maillefer, Swiss). Master apical file was maintained as #35 K-file. All canals of the experimental teeth were obturated with continuous wave method using System B(Analytic technology, U.S.A.) The teeth were randomly divided into three experimental groups of 15 and two control groups of 4. Experimental group 1 was obturated with Sealapex and group 2 with Pulp canal sealer, and group 3 with AH26. A dual chamber anaerobic bacterial leakage model was assembled. Brain heart infusion with yeast extract, hemin, menadion, and the chromogenic indicator bromocresol purple was used as the culture broth for Fusobacterium nucleatum(VPI 10197), The specimens were incubated in anaerobic chamber at $37^{\circ}C$ and were observed every 2 to 3 clays, The coronal leakage was evaluated through the color change of culture broth in lower chamber for 60 days. The results were as follows: 1. The incidence of bacterial leakage in group 1 (Sealapex group was 80%, 53% in group 2 (Pulp canal sealer), 27% in group 3 (AH26). 2. There were statistically significant differences in leakage scores between group 1 and group 2, and between group 1 and group 3, respectively. (P<0.05) 3. There was no significantly difference in leakage score between group 2 and group 3. (P>0 05)

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.6017-6037
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• 2017

In a multi-resolution image encoding system, the image is encoded into a single file as a layer of bit streams, and then it is transmitted layer by layer progressively to reduce the transmission time across a low bandwidth connection. This encoding scheme is also suitable for multiple decoders, each with different capabilities ranging from a handheld device to a PC. In our previous work, we proposed an edge adaptive hierarchical interpolation algorithm for multi-resolution image coding system. In this paper, we enhanced its compression efficiency by adding three major components. First, its prediction accuracy is improved using context adaptive error modeling as a feedback. Second, the conditional probability of prediction errors is sharpened by removing the sign redundancy among local prediction errors by applying sign flipping. Third, the conditional probability is sharpened further by reducing the number of distinct error symbols using error remapping function. Experimental results on benchmark data sets reveal that the enhanced algorithm achieves a better compression bit rate than our previous algorithm and other algorithms. It is shown that compression bit rate is much better for images that are rich in directional edges and textures. The enhanced algorithm also shows better rate-distortion performance and visual quality at the intermediate stages of progressive image transmission.

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.202-211
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• 2000

The aim of this study was to compare the apical sealing ability of a new thermoplasticized gutta-percha filling technique, the Easy Filling and the Quick Obturation system with lateral condensation technique and Thermafil system to evaluate their clinical acceptabilities. Fifty-two extracted single-rooted teeth were instrumented to #35 using the .04 taper ProFile system. Four groups of 12 teeth were obturated by lateral condensation technique. Thermafil system and two new thermoplasticized gutta-percha techniques, the Easy Filling system and Quick Obturation system (Meta Dental co. Ltd. Korea), respectively. Four teeth served as controls. After the teeth were immersed in 2% methylene blue dye for 48 hours, they were resected horizontally at 1mm to 5mm level from the anatomical apex using a low-speed microtome. Each section was examined under a stereomicroscope at ${\times40}$ magnification and photographed. After each image was scanned, the leakage area was measured at each level using Brain 3 (Nosdia Tech., Korea) software. Leakage ratio was calculated for each group and was analyzed statistically to come up with the following results: 1. At 1mm level, the Quick Obturation system had the largest amount of apical leakage and it was statistically significant when compared with the lateral condensation group and the Thermafil group (p<0.05). 2. At 2mm and 3mm level, there were no significant difference of apical leakage among all four groups (p>0.05), and from 4mm level, no apical dye penetration was observed in all the groups. In conclusion, the apical seal produced by Easy Filling system and the Quick Obturation system was comparable to lateral condensation technique and Thermafil system except for the 1mm level. More improvement of the apical seal can be expected as the operator becomes skillful with the new techniques.

• The KIPS Transactions:PartA
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• v.13A no.6 s.103
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• pp.517-524
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• 2006

In cluster computers, it is essential to Implement the single I/O space(SIOS) supporting integrated I/O substructure to efficiently process I/O intensive applications. SIOS service provides with global I/O address space to directly access peripherals and hard disks in its own or remote nodes from any node in the cluster computer In this thesis, we propose the implementation method of SIOS in Linux clusters by using only freewares. This method is implemented at device driver level that uses Enhanced Network Block Device(ENBD) and file system level that uses S/W RAID and NFS. The major strengths of this method are easiness of implementation and almost no cost due to using freewares. In addition, since freewares used are open sources, it is possible to apply this method to other platforms with only slight modification. Moreover, experiments show that I/O throughputs are up to 5.5 times higher in write operations and approximately 2.3 times higher in read operations than those of CDD method that uses the device driver developed at kernel level.

• Journal of The Korean Association of Information Education
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• v.11 no.1
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• pp.11-19
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• 2007

The 7th education curriculum requires for the aggressive collection and reflection of demands of students, teachers, parents, and local community, necessary for the school operation. In this regard, this study attempts to design and establish the web questionnaire system for the effective school operation. Web-based Survey system, presented in this study, is designed by being divided into administrator(investigator) and respondents, and administrator can manage questionnaires and identify the results by just connecting Internet. In addition, it is designed to do question drawing and statistics in real time within the system without the separate program, by providing file database related to the questions. This system makes the questionnaire survey of school unit easy and fast by being used as a menu in the homepage of school and operated as a single system.

• Journal of Arbitration Studies
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• v.30 no.3
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• pp.47-66
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• 2020

Due to the division of China's departmental laws, the disconnect between theory and practice, and the influence of traditional academic thinking on the understanding of the knowledge structure of arbitration legal talents in practice, the construction of law school colleges, teaching teams, and research centers mostly revolves around departmental laws, tearing the connection of the arbitration legal system. The student-centered, process-guaranteed, and result-oriented arbitration master of law training model is "virtualized," the shaping of arbitration professionalism is ignored, the coverage of practical teaching is narrowed, and the arbitration legal profession is mostly formalized. The prevalence of specialized curriculum systems shortage, single faculty, formalized practical teaching, outdated curriculum settings, unsuitable curriculum system design for development, and inaccurate professional curriculum standards and positioning renders it difficult to integrate the "Belt and Road." The cutting-edge, the latest research results, and practical experience cannot reflect the connotation, goals, and requirements of "Entrepreneurship" education, as well as arbitral issues such as the ineffective monitoring of practical education and the inconsistent evaluation of standards and scales. Under the background of the "Belt and Road," based on system theory and practice and through training goals that innovate and initiate organizational form, activity content, management characteristics, assessment and support conditions, etc., the arbitration law teaching curriculum system is gradually improved and integrated. Through the establishment of a "Belt and Road" arbitration case file database and other measures, a complete arbitration law theory and practice teaching guarantee system has been established. Third parties are introduced, arbitration law experimental modules are developed, students are guided how to discover new knowledge, new contents are mastered, solidarity, cooperation, and problem-solving capabilities are cultivated in the practice of the "Belt and Road," and quality education, vocational education, and innovation education are organically integrated. In order to implement the requirements of arbitration law education, innovation development and collaborative management of arbitration law teaching practice base should be cultivated, thus giving full play to the effect of collaborative education between universities and arbitration institutions.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.161-164
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• 2005

As the power of influence of the Internet grows steadily, attacks against the Internet can cause enormous monetary damages nowadays. A worm can not only replicate itself like a virus but also propagate itself across the Internet. So it infects vulnerable hosts in the Internet and then downgrades the overall performance of the Internet or makes the Internet not to work. To response this, worm detection and prevention technologies are developed. The worm detection technologies are classified into two categories, host based detection and network based detection. Host based detection methods are a method which checks the files that worms make, a method which checks the integrity of the file systems and so on. Network based detection methods are a misuse detection method which compares traffic payloads with worm signatures and anomaly detection methods which check inbound/outbound scan rates, ICMP host/port unreachable message rates, and TCP RST packet rates. However, single detection methods like the aforementioned can't response worms' attacks effectively because worms attack the Internet in the distributed fashion. In this paper, we propose a design of distributed worm detection system to overcome the inefficiency. Existing distributed network intrusion detection systems cooperate with each other only with their own information. Unlike this, in our proposed system, a worm detection system on a network in which worms select targets and a worm detection system on a network in which worms propagate themselves cooperate with each other with the direction-aware information in terms of worm's lifecycle. The direction-aware information includes the moving direction of worms and the service port attacked by worms. In this way, we can not only reduce false positive rate of the system but also prevent worms from propagating themselves across the Internet through dispersing the confirmed worm signature.

• The Journal of the Korean dental association
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• v.55 no.1
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• pp.63-70
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• 2017

Materials and methods: Sixty extracted premolars were assigned to three groups according to the root canal system (Weine's classification; type I, II and III) of 20 teeth each using radiographic examination. The root tip was cut horizontally 1 mm from the anatomical apex and the apical cross-section was visualized using microscope at x50 magnification and photographed. Minimum and maximum apical root canal diameter of each tooth was measured and classified into three types by canal morphology (round, oval and flattened shape). Statistical analysis was performed to compare the apical root canal diameter and morphology according to the root canal system. Results: In apical root canal morphology at cross-sectional view, the most common shape was round in type I, flat in type II, and oval in type III. In apical root canal diameters at cross-sectional view, there was a significant difference between the minimum and maximum diameter in all types (p<0.05). The maximum diameter was 0.331 mm in type I, 0.519 mm in type II, and 0.310 mm in type III. There was a significant difference among type I, III and type II (p<0.05). Conclusion: The morphology and diameter of apical root canal was different according to the root canal system. Therefore, clinicians should consider the apical file size in view of the apical root canal shape according to the root canal system.

• The KIPS Transactions:PartC
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• v.8C no.6
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• pp.765-774
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• 2001

In this paper, we proposed the striping policy for the storage nodes in the Linux-based parallel media stream server. We newly developed a storage clustering architecture, and named it as a system RAID architecture. In this system, many storage cluster nodes are grouped to operate as a single server. This system uses unique striping policy to distribute multimedia files into the parallel storage nodes. If a service request occurs, each storage cluster node transmits striped files concurrently to the clients. This scheme can provide the fair distribution of the preprocessing load in all storage cluster nodes. The feature of this system is a relative striping policy based on the file types, service types, and the number of storage nodes to provide the best service.

• The Journal of Advanced Prosthodontics
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• v.8 no.3
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• pp.219-223
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• 2016

PURPOSE. This study aimed to create a digitized database of fabricated obturators to be kept for patients' potential emergency needs. MATERIALS AND METHODS. A chairside intraoral scanner was used to scan the surfaces of an acrylic resin obturator. The scanned data was recorded and saved as a single standard tessellation language file using a three-dimensional modeling software. A simulated obturator model was manufactured using fused deposition modeling technique in a three-dimensional printer. RESULTS. The entire obturator was successfully scanned regardless of its structural complexity, modeled as three-dimensional data, and stored in the digital system of our clinic at a relatively small size (19.6 MB). A simulated obturator model was then accurately manufactured from these data. CONCLUSION. This study provides a proof-of-concept for the use of digital technology to create a digitized database of obturators for edentulous maxillectomy patients.