• Journal of computational fluids engineering
• /
• v.4 no.1
• /
• pp.53-61
• /
• 1999

Two-dimensional, unsteady, incompressible and compressible Navier-Stokes codes are developed for the computation of the viscous turbulent flow over high-lift airfoils. The compressible code involves a conventional upwind-differenced scheme for the convective terms and LU-SGS scheme for temporal integration. The incompressible code with pseudo-compressibility method also adopts the same schemes as the compressible code. Three two-equation turbulence models are evaluated by computing the flow over single and multi-element airfoils. The compressible and incompressible codes are validated by predicting the flow around the RAE 2822 transonic airfoil and the NACA 4412 airfoil, respectively. In addition, both the incompressible and compressible code are used to compute the flow over the NLR 7301 airfoil with flap to study the compressible effect near the high-loaded leading edge. The grid systems are efficiently generated using Chimera overlapping grid scheme. Overall, the κ-ω SST model shows closer agreement with experiment results, especially in the prediction of adverse pressure gradient region on the suction surfaces of high-lift airfoils.

• Journal of KIISE:Information Networking
• /
• v.35 no.4
• /
• pp.355-366
• /
• 2008

This paper proposes a mobile SCTP (mSCTP) handover scheme for vertical handover between 3G wireless and WiBro networks. To evaluate the proposed mSCTP vertical handover scheme, we implement the mSCTP handover supporting system over Linux platform in which the movement of a mobile node is automatically detected and the mSCTP vertical handover is performed by the mobile node. We analyze and compare the performance of mSCTP handover and Mobile IP handover over the preconfigured testbed. From the numerical results, we can see that the handover latency of mSCTP could be much more reduced, compared to the Mobile IP handover, if the mobile node would sojourn long enough in the overlapping region between the two heterogeneous networks.

• The KIPS Transactions:PartB
• /
• v.15B no.2
• /
• pp.81-86
• /
• 2008

This paper discusses the problem of partial object recognition in image databases. We propose the method to reconstruct and estimate partially occluded shapes and regions of objects in images from overlapping and cutting. We present the robust method for recognizing partially occluded objects based on symmetry properties, which is based on an ellipse of objects. Our method provides simple techniques to reconstruct occluded regions via a region copy using the symmetry axis within an object. Since our method relies on reconstruction of the object based on the symmetry rather than statistical estimates, it has proven to be remarkably robust in recognizing partially occluded objects in the presence of scale changes, rotation, and viewpoint changes.

• Microbiology and Biotechnology Letters
• /
• v.25 no.6
• /
• pp.571-579
• /
• 1997

For the overproduction of pectate lyase (PL), the recombinant plasmid pl2BS fl which has strong promoter from alkali-tolerent Bacillus sp. YA-14 was used. In order to overexpress the pectate lyase by the action of overlapping strong promoter in pl2BS$\Delta$fl, 1.6 kb of PL gene was inserted into pl2BS$\Delta$fl to form pl2BS$\delta$f1-PL and the enzyme was expressed. But decreased expression efficiency of the PL gene was observed and it was due to the presence of the transcription terminator region on the upstream of the PL gene. The transcription terminator of the PL gene in pl2BS$\delta$f1-PL was removed and the resulting plasmid p12BS$\Delta$fl$\Delta$PL was formed. Bacillus subtilis 207-25 harboring the recombinant plasmid, p12BS$\Delta$fl$\Delta$PL, revealed increased expression efficiency with chloramphenicol induction when cat-86 was used as a reporter gene.

• Journal of Korea Multimedia Society
• /
• v.18 no.6
• /
• pp.701-709
• /
• 2015

Image stitching method is a technique for obtaining an high-resolution image by combining two or more images. In X-ray image for clinical diagnosis, the size of the imaging region taken by one shot is limited due to the field-of-view of the equipment. Therefore, in order to obtain a high-resolution image including large regions such as a whole body, the synthesis of multiple X-ray images is required. In this paper, we propose a rapid stitching method of digital X-ray images using template-based registration. The proposed algorithm use principal component analysis(PCA) and k-nearest neighborhood(k-NN) to determine the location of input images before performing a template-based matching. After detecting the overlapping position using template-based matching, we synthesize input images by alpha blending. To improve the computational efficiency, reduced images are used for PCA and k-NN analysis. Experimental results showed that our method was more accurate comparing with the previous method with the improvement of the registration speed. Our stitching method could be usefully applied into the stitching of 2D or 3D multiple images.

• Journal of Institute of Control, Robotics and Systems
• /
• v.17 no.2
• /
• pp.79-87
• /
• 2011

This paper presents the optimal design of an overlapped ultrasonic sensor ring for high resolution obstacle detection of an autonomous mobile robot. It is assumed that a set of low directivity ultrasonic sensors of the same type are arranged along a circle of nonzero radius at a regular spacing with their beams overlapped. First, taking into account the dead angle region, the entire range of obstacle detection is determined with reference to the center of an overlapped ultrasonic sensor ring. Second, the optimal design index of an overlapped ultrasonic sensor ring is defined as the area closeness of three sensing subzones resulting from beam overlap. Third, the lower and upper bounds on the number of ultrasonic sensors are derived, which can guarantee minimal beam overlap and also avoid excessive beam overlap among adjacent ultrasonic sensors. Fourth, employing a commercial low directivity ultrasonic sensor, an optimal design example of an overlapped ultrasonic sensor ring is given along with the ultrasonic sensor ring prototype mounted on top of a mobile robot. Finally, some experimental results using our prototype ultrasonic sensor ring are given to demonstrate the validity and performance of an optimally overlapped ultrasonic sensor ring for high resolution obstacle detection.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.42 no.6
• /
• pp.379-382
• /
• 2016

Cutaneous lymphoid hyperplasia (CLH) is a cutaneous pseudolymphoma with a worldwide distribution, equally affecting all races and ethnic groups. Due to its vast array of characteristics, it is most often missed in the differential diagnosis of firm to soft lumps on the head and neck. A systematic approach to the workup and diagnosis along with treatment of such lesions is discussed in this article. A 20-year-old Asian Indian female presented to our Oral and Maxillofacial unit with a lump on the left side of her forehead for 1 month. Local examination revealed a $2.5{\times}3.0cm^2$, well circumscribed swelling over the left para median region that was firm to doughy and non-tender. There was no other significant finding on general examination. Excisional biopsy of the lesion was performed, followed by histopathologic processing. The general etiology, pathogenesis, clinical presentation, differential diagnosis, clinical course, prognosis, treatment, and prevention have been discussed in line with the recent modalities of diagnosis and treatment of CLH. Due to the overlapping clinical and histological characteristics of CLH with many other lesions, it is important to consider this lesion in the differential diagnosis of cutaneous lesions.

• The Bulletin of The Korean Astronomical Society
• /
• v.43 no.1
• /
• pp.63.3-63.3
• /
• 2018

A comparison study between two low temperature opacity tables has been conducted. The opacity is the one of the major input physics in stellar model construction. Opacity is generally provided in a tabular form and as a function of 3 parameters, ie, density, temperature and chemical composition. Among available opacity tables, it has been common practice to utilize OPAL opacity table (Iglesias & Rogers, 1996) augmented with Ferguson opacity table (Ferguson et al. 2005) for the low temperature domain. For low temperature domain, another table, AESOPUS (Marigo & Aringer, 2009), has been announced in 2007. Reportedly, this opacity covers even lower temperature region, and is compatible with that of Ferguson in the overlapping temperature domain. To test the compatibility, stellar models and isochrones for various ranges in mass, metallicity and chemical composition, have been constructed. It is confirmed that there is no significant difference in the stellar models and isochrones constructed with the two different low temperature opacities. Therefore, in the construction of stellar models and isochrones, Ferguson low temperature opacity can be replaced with the AESOPUS opacity. The wider range in the temperature and chemical mixtures, and the easier accessibility make AESOPUS favorable in practical purpose.

• Imaging Science in Dentistry
• /
• v.44 no.1
• /
• pp.67-73
• /
• 2014

Intraosseous vascular lesions of the maxillofacial region are rare, and the differential diagnosis of intraosseous vascular malformations from other jaw lesions can be challenging. In the present case, magnetic resonance imaging and three-dimensional computed tomographic angiography (CTA) was used for diagnosis, and the lesion was treated wih surgical excision. Diverse characteristics such as the "honeycomb" and "sunburst" radiographic appearances and the absence of major peripheral feeder vessels in the CTA were noted. Intraosseous vascular malformations have a varied radiographic appearance, and the nomenclature of these lesions is equally diverse, with several overlapping terms. Pathologists do not generally differentiate among intraosseous vascular lesions on the basis of histopathology, although these lesions may present with contrasting immunohistochemical and clinical behaviors requiring varied treatment strategies. This case report highlights the need for multiple imaging modalities to differentiate among vascular lesions, as well as to better understand the behaviors of these unique lesions.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.8
• /
• pp.1805-1812
• /
• 2011

Bandpass sampling technique has an advantage that it uses lower sampling frequency than Nyquist criterion. But special care is required in choosing sampling frequency to avoid self-image overlapping in the first Nyquist region. Recently, the second-order BPS techniques which can suppress possible self-image by using an additional ADC and by employing digital signal processing have been proposed. This paper addresses a complex BPS based SDR front-end. Unlike general second-order BPS, it needs simple FIR filter to compensate delay in the second ADC. We show a method to find proper sampling frequencies to down convert RF signals selected by tunable RF filter operating in arbitrary frequency range.