• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.935-940
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• 2013

Background: To evaluate the diagnostic utility of conventional ultrasonography and real time ultrasound elastography in differentiating degenerating cystic thyroid nodules mimicking malignancy from papillary thyroid carcinoma. Methods: We retrospectively analyzed conventional ultrasonographic and elastographic characteristics of 19 degenerating cystic thyroid nodules mimicking malignancy in 19 patients, with 30 surgically confirmed PTCs as controls. Based on size, the nodules had been grouped into less than 10mm (group A) and greater than 10 mm (group B). We evaluated conventional parameters and elasticity pattern. Color-scaled elastograms were graded as to stiffness of nodules using an elasticity pattern from I (soft) to IV (stiff). Results: Degenerating cystic thyroid nodules were similar to PTCs in conventional ultrasonographic findings, but the former frequently showed oval to round in shape (group A, 69.2% vs 18.8%, P=0.017; group B, 66.7% vs 7.14%, P=0.017) and punctuate hyperechoic foci (group A, 61.5% vs 0, P<0.001; group B, 50% vs 0, P<0.001). On real time ultrasound elastography, 7 of 13 degenerating cystic thyroid nodules in group A were pattern I, 5 were pattern II, 1 was pattern III. One degenerating cystic thyroid nodule in group B was pattern II, 5 were pattern III. The area under the curve for elastography was 0.98 in group A (sensitivity 92.3%, specificity 100%, P = 0.002), and 0.88 in group B (sensitivity 16.7%, specificity 100%, P = 0.014). Conclusions: As a dependable imaging technique, elastography helps increase the performance in differential diagnosis of degenerating cystic thyroid nodule and malignancy.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.9_10
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• pp.441-451
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• 2008

Currently, the X.509 proxy certificate is widely used to delegate an entity's right to another entity in the computational grid environment. However it has two drawbacks: the potential security threat caused by intraceability of a delegation chain and the inefficiency caused by an interactive communication between the right grantor and the right grantee on the delegation protocol. To address these problems for computational grids, we propose a new delegation protocol without additional cost. We use an ID-based key generation technique to generate a proxy private key which is a means to exercise the delegated signing right. By applying the ID-based key generation technique, the proposed protocol has the delegation traceability and the non-interactive delegation property. Since the right delegation occurs massively in the computational grid environment, our protocol can contribute the security enhancement by providing the delegation traceability and the efficiency enhancement by reducing the inter-domain communication cost.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.544-549
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• 2008

National Education Information System (NEIS) is an ambitious reform project in the field of education, which is launched mainly by government initiative and is to link administrational work of between schools and their senior administration offices via internet. NEIS is introduced to lighten the teachers' overburden, to standardize the work process and to bring better quality education to each classroom and make it possible for those involved in education to resolve any related educational problem on line. This paper aims to construct a hierarchy model consisting of key factors such as administrative and technological factors for the effective use of NEIS and to evaluate the relative importance among key factors using multiple decision-making technique. Eventually, the analysis results can be utilized to develop the future improvement strategy of NEIS and to satisfy the users.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4624-4640
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• 2017

This paper mainly presents a secure and efficient e-Medical Record System via searchable encryption scheme from asymmetric pairings, which could provide privacy data search and encrypt function for patients and doctors in public platform. The core technique of this system is an extension public key encryption system with keyword search, which the server could test whether or not the files stored in platform contain the keyword without leaking the information about the encrypted file. Compared with former e-medical record systems, the system proposed here has several superior features: (1)Users could search the data stored in cloud server contains some keywords without leaking anything about the origin data. (2) We apply asymmetric pairings to achieve shorter key size scheme in the standard model, and adopt the dual system encryption technique to reduce the scheme's secure problem to the hard Symmetric External Diffie-Hellman assumption, which could against the variety of attacks in the future complex network environment. (3) In the last of paper, we analyze the scheme's efficiency and point out that our scheme is more efficient and secure than some other classical searchable encryption models.

• Wind and Structures
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• v.22 no.6
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• pp.663-684
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• 2016

Conical vortices generated at the corner regions of large-span flat roofs have been investigated by using the Particle Image Velocimetry (PIV) technique. Mean and instantaneous vector fields for velocity, vorticity, and streamlines were measured at three visual planes and for two different flow angles of $15^{\circ}$. The results indicated that conical vortices occur when the wind is not perpendicular to the front edge. The location of the leading edge corresponding to the negative peak vorticity and maximum turbulent kinetic energy was found at the center of the conical vortex. The wind pressure reaches the maximum near the leading edge roof corner, and a triangle of severe suctions zone appears downstream. The mean pressure in uniform flow is greater than that under turbulent flow condition, while a significant increase in the fluctuating wind pressure occurs in turbulent streams. From its emergence to stability, the shape of the vortex cross-section is nearly elliptical, with increasing area. The angle that forms between the vortex axis and the leading edge is much smaller in turbulent streams. The detailed flow structures and characteristics obtained through FLUENT simulation are in agreement with the experimental results. The three dimensional (3-D) structure of the conical vortices is clearly observed from the comprehensive arrangement of several visual planes, and the inner link was established between the vortex evolution process, vortex core position and pressure distribution.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.1
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• pp.319-323
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• 2012

Objective: To explore the feasibility of shrinking field technique after 40 Gy radiation through 18F-FDG PET/CT during treatment for patients with stage III non-small cell lung cancer (NSCLC). Methods: In 66 consecutive patients with local-advanced NSCLC, 18F-FDG PET/CT scanning was performed prior to treatment and repeated after 40 Gy. Conventionally fractionated IMRT or CRT plans to a median total dose of 66Gy (range, 60-78Gy) were generated. The target volumes were delineated in composite images of CT and PET. Plan 1 was designed for 40 Gy to the initial planning target volume (PTV) with a subsequent 20-28 Gy-boost to the shrunken PTV. Plan 2 was delivering the same dose to the initial PTV without shrinking field. Accumulated doses of normal tissues were calculated using deformable image registration during the treatment course. Results: The median GTV and PTV reduction were 35% and 30% after 40 Gy treatment. Target volume reduction was correlated with chemotherapy and sex. In plan 2, delivering the same dose to the initial PTV could have only been achieved in 10 (15.2%) patients. Significant differences (p<0.05) were observed regarding doses to the lung, spinal cord, esophagus and heart. Conclusions: Radiotherapy adaptive to tumor shrinkage determined by repeated 18F-FDG PET/CT after 40 Gy during treatment course might be feasible to spare more normal tissues, and has the potential to allow dose escalation and increased local control.

• Fire Science and Engineering
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• v.15 no.4
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• pp.64-70
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• 2001

This study suggests fire, explosion safety assessment items and risk assessment technique for underground shopping malls by extracting dangerous elements in the management stage through examination of related accidents, documents and present conditions. This will also suggest importance of seven items to be key indices for a counterplan by classifying characteristics and trends of the large scale, depth and complexity of underground shopping malls.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.3
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• pp.24-29
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• 2004

The grinding process plays a key role which decides the quality of a product finally. But the grinding process is very irregular, so it is very difficult to analyse the process accurately. Therefore it is very important in the aspect of precision and automation to reduce the idle time and to decide the proper dressing time by watching. In this study, we choose the method which can be observed directly by using of computer vision and then apply pattern classification technique to the method of measuring the wheel surface. Pattern classification technique is proper to analyse complicated surface image. We observe the change of the wheel surface by using of the gray level run lengths which are representative in this technique.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.2
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• pp.138-143
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• 2000

The establishment of a practical ultra-precision grinding technique using Diamond and CBN wheels is one of the major key technolo-gies to improve production techniques for machine-to-difficult materials without finishing process such as lapping and polishing. But the special efficient dressing technique for ultra-fine grit type grinding wheels to stabilize the grinding ability was not developed. Recently electrolytic in-process dressing technique is proposed to ultra-fine grit type metal bonded diamond wheels to protrude abra-sives continuously from the tool surface. This technology can be widely used to surface grinding and cylindrical grinding but cannot be used efficiently to internal grinding because of the electrode attachment trouble. This paper describes the effect of interval type electrolytic dressing as proposed newly to cast iron bonded diamond wheel for efficient internal grinding with mirror type high quality ground surface.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1072-1075
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• 1996

In hot rolling process at steel plant, cooling of the rolled strip at the exit of the rolling mill is one of the most important processes that would decide the quality of products. To guarantee the thermal equity over the strip, the device called an edge-masking unit is being used. That is installed between the strip and the sprayers to cover the side edge of the strip from spraying water. The accuracy of positioning the bracket is the key to this operation. A machine vision technique can be applied to measure the position of the side edges before an as-rolled strip enters into the cooling facility to rectify the error of preset position of the bracket. This paper shows the simulation result of applying the machine vision technique to measuring the position of a strip and suggests the solution for the target.