Enhanced high dynamic-range image rendering using a surround map based on edge-adaptive layer blurring

Hyuk-Ju Kwon,Sung-Hak Lee,Geun-Young Lee,Kyu-Ik Sohng IET 2016 IET computer vision Vol.10 No.7

<P>Many tone-mapping methods have developed efficient tone compression and local contrast enhancement techniques for high dynamic-range imaging. Local tone mapping enhances the image quality to reveal the details; however, it causes artefacts such as halos. Halo artefacts appear around the edges of an image and lead to deterioration in the overall image quality. Detail-base separation and multi-scale methods have been developed to reduce halo artefacts. Detail-base separation methods divide the image into a detail layer and base layer using an edge-preserving filter and process each layer independently. Multi-scale methods alleviate artefacts such as halos, noise, and awkward global toning using a weighted sum of single-scale images. These methods have several inherent problems including the complexity of the edge-preserving filter and multi-processing redundancy. Therefore, in this study, a novel surround map is presented to resolve halo artefacts and enhance local details in single-scale processing.</P>

Expression Patterns of Ki-67, Cyclin A, and Cyclin D1 during Tooth Development

Hyuk-Jae Kwon(권혁제),Kyung-Sik Yoon(윤경식),Han-Sung Jung(정한성) 대한체질인류학회 2013 해부·생물인류학 (Anat Biol Anthropol) Vol.26 No.1

치아발생 및 형태형성 과정에서 치아상피와 치아간엽을 구성하는 세포는 동적인 세포주기의 변화가 일어난다. 현재까지 세포증식은 치아발생에 중요한 현상으로 알려져 있지만, 치아발생 중에 일어나는 복잡한 분자적 기전과 연관해서 세포주기의 각 시기가 어떻게 관여하는지에 대해서는 충분한 연구가 이루어지지 않았다. 그러므로 본 연구는 치아발생 기전과 세포주기의 시기의 변화와의 관계를 밝히고자 하였다. 치아발생 과정에서 일어나는 형태변화를 확인하기 위해 싹시기, 모자시기, 종시기의 쥐 앞니 및 어금니 치배를 헤마톡실린-에오신으로 염색하여 조직학적으로 관찰하였다. 또한 세포주기 시기의 표지자인 Ki-67, 싸이클린 A, 싸이클린 D1의 발현양상을 관찰하기 위해 면역조직화학염색을 시행하였다. 싹시기, 모자시기, 종시기에서 증식하는 세포들은 Ki-67과 싸이클린 A를 발현하는 것을 확인하였다. 싸이클린 D1은 앞니의 상아질모세포 및 모자시기의 사기질결절에서 특이적인 발현을 보였으며, 이곳에서는 Ki-67이나 싸이클린 A가 발현되지 않는다는 것을 발견하였다. 본 연구는 치아발생 중 각 주요 시기에서 세포주기의 변화를 관찰하였으며, 이는 치아발생에 관여하는 기전에 대한 중요한 정보를 제공한다. 또한 본 연구의 결과는 지금까지의 앞니의 사기질모세포 및 사기질결절의 특성에 대한 지식을 이해하는 데에 중요한 자료가 될 것으로 사료된다. Dental epithelial and mesenchymal cells that form the teeth undergo dynamic changes in cell cycle during tooth development and morphogenesis. Although proliferation has been known as a key event during odontogenesis, the cell cycle phases and their relations with the complicated molecular mechanisms of tooth development are not fully understood yet. This study comparatively examined the expression patterns of Ki-67, cyclin A, and cyclin D1 during tooth development in the mouse incisor and molar in order to identify the cellcycle characteristics during odontogenesis. We found that Ki-67 and cyclin A were expressed in the proliferating cells in the dental epithelial and mesenchymal tissues at the bud, cap and bell stages. Cycln D1 showed distinct expression in the incisor odontoblast region and the enamel knot, in which Ki-67 nor cyclin A was expressed. Our results provide specific information on the cell cycle phases during tooth development that may provide clues to relate them with the complex odontogenic mechanisms. Furthermore, we suggest that our findings enlightened the previous studies on the incisor odontoblasts and the enamel knot during tooth development.

A Theoretical Model of Critical Heat Flux in Flow Boiling at Low Qualities

Hyuk Sung Kwon,Dae Hyun Hwang,Ho Young Kim,Yong Chan Kim 대한기계학회 2001 KSME International Journal Vol.15 No.7

Comparing the Characteristics of Patients With Newly Diagnosed Dementia Before and After 2008 in Seoul, South Korea: A Population-Based Study

Hyuk Sung Kwon,정용휘,Sojeong Park,Dae Ryong Kang,Hojin Choi 대한신경과학회 2022 Journal of Clinical Neurology Vol.18 No.6

A phase II study of modified FOLFOX-4 for colorectal cancer patients with peritoneal carcinomatosis

( Hyuk Chan Kwon ),( Sung Hyun Kim ),( Sung Yong Oh ),( Su Ee Lee ),( Ji Hyun Lee ),( Hyo Jin Kim ) 대한내과학회 2011 대한내과학회 추계학술대회 Vol.2011 No.1

Background: Peritoneal carcinomatosis (PC) of colorectal cancer (CRC) is common and is the second most common cause of death. Clinical studies regarding chemotherapy for CRC with PC have been classically rather limited in scope. We have evaluated the efficacy of modified FOLFOX-4 (m-FOLFOX) regimen for PC of CRC origin. Methods: CRC patients with PC were treated with cycles of oxaliplatin at 85 mg/m2 on day 1, leucovorin 20 mg/m2 followed by 5-fluorouracil (5-FU) via a 400 mg/m2 bolus and a 22 h continuous infusion of 600 mg/m2 5-FU on Days 1-2 at 2-week intervals. Results: Forty patients participated in this study. Median age was 55 years. Thirty two patients (80.0%) received previous operation, and 60.0% of PC occurred synchronously, Thirty-five patients were assessable and exhibited measurable lesions. Two patients (5.7%) demonstrated complete response and six patients (17.1%) evidenced partial responses. The median overall survival time was 21.5 months (95% CI: 17.2-25.7 months).There was no treatment related death. Patients with low CEA level (37.2 vs. 15.6 months, p=0.001), or who received operation (22.5 vs. 6.8 months, p=0.040) showed better survival. Conclusion: The m-FOLFOX-4 regimen was determined to be effective for CRC patients with PC.

Integrated GUI Environment of Parallel Fuzzy Inference System for Pattern Classification of Remote Sensing Images

Sang Gu Lee,Ki Sung Son,Jong Hyuk Kim,Byung Kwon Lee,Seong Hoon Lee 한국지능시스템학회 2002 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.2 No.2

Performance analysis of a wavelength-locked Fabry-Perot laser diode by light injection of an external spectrally sliced Fabry-Perot laser diode

Kwon, Hyuk-Choon,Han, Sang-Kook The Optical Society 2006 Applied Optics Vol.45 No.24

<P>We have analyzed and experimentally demonstrated the performance of a wavelength-locked Fabry-Perot laser diode (FP-LD) with a spectrally sliced FP-LD as an external-injection optical source. A high side-mode suppression ratio exceeding 30 dB was obtained, and the noise characteristic of the wavelength-locked FP-LD was analyzed in terms of both mode partition noise and interferometric noise. The measured relative intensity noise had a minimum value of -140 dB/Hz. We also investigated the transmission characteristics such as the Q factor and extinction ratio for a 622 Mbits/s and 2.5 Gbits/s baseband digital signal.</P>

A phase II study of modified FOLFOX-4 for colorectal cancer patients with peritoneal carcinomatosis

( Hyuk-chan Kwon ),( Sung Hyun Kim ),( Sung Yong Oh ),( Suee Lee ),( Ji Hyun Lee ),( Hyo-jin Kim ) 대한내과학회 2011 대한내과학회 추계학술대회 Vol.2011 No.-

Lessons Learned in Improvement Work of Fuel Handling Equipment at Operating Nuclear Power Plants

Sang-Gyoon Chang,Won-Bae Park,Min-Gyu Kim,Dae-Hyuk Kwon 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.2

The purpose of this study is to provide lessons learned in the experience of improvement work of fuel handling equipment at operating nuclear power plants. The upgrade of fuel handling equipment for safety enhancement and performance improvement has been going on for 15 years since the early 2000’s. The main goal is to increase fuel loading/unloading capability of the equipment from about 2.5 fuel assemblies per hour to more than six (6). It is achieved with sequential operations of three (3) fuel handling equipment, which consists of the refueling machine, the fuel transfer system and the spent fuel handling machine. The scope of the upgrade for fuel handling equipment is summarized as follows. The PC data control system based on PLC for interlocks and high speed motor drive system is introduced for better operating efficiency. The motors and drives for bridge, trolley, and hoist are replaced with AC servomotors and drivers, respectively. The fuel transfer system has an auto-initiation feature operating from the refueling machine or the spent fuel handling machine. The winch motor and drive for the carriage of fuel transfer system is also replaced with AC servomotors and drivers. And some of HPU (hydraulic power units) equipment for each building (reactor containment building and fuel handling building) are replaced to improve their function. The considerations for improvement of fuel handling equipment are as belows. 1) Fuel handling should be consistent with the instructions provided by the fuel designer and/or manufacturer, which are for Standard type fuel and Westinghouse type fuel, used in domestic nuclear power plants. Each fuel has unique design characteristics, which are PLC setpoints for overload and underload, slow speed zones for a bridge, trolley and hoist, allowable acceleration/deceleration value in handling, hoist elevation and manual speed in off-index operation at reactor. 2) The interlock system should be designed in accordance with design criteria specified by the utilities of nuclear power plant. 3) Performance should be improved according to the operating characteristics of the fuel handling equipment. High-speed and optimization of FTS upender and carriage are essential for operating performance so that its modification should be considered first. And the low speed and range in the operation mechanism of the hoist should be designed to comply with guidelines. 4) The accident analysis through self-diagnosis function and operation history in modification at domestic operating nuclear power plants would be good lessons learned. It is advisable to utilize such various information as it can help to improve reliability of nuclear fuel handling operation and power plant operation rate.

Neuroprotective Effects of GV1001 in Animal Stroke Model and Neural Cells Subject to Oxygen- Glucose Deprivation/Reperfusion Injury

Hyuk Sung Kwon,Ye Eun Kim,박현희,손정우,최호진,이영주,Hyun Young Kim,이규용,고성호 대한뇌졸중학회 2021 Journal of stroke Vol.23 No.3

Background and Purpose Previous studies have revealed the diverse neuroprotective effects of GV1001. In this study, we investigated the effects of GV1001 on focal cerebral ischemia-reperfusion injury (IRI) in rats and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced injury in neural stem cells (NSCs) and cortical neurons. Methods Focal cerebral IRI was induced by transient middle cerebral artery occlusion (MCAO). Brain diffusion-weighted imaging (DWI) was performed 2 hours after occlusion, and a total of 37 rats were treated by reperfusion with GV1001 or saline 2 hours after occlusion. Fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging, immunohistochemistry, and neurobehavioral function analyses were performed. Additionally, OGD/R-injured NSCs and cortical neurons were treated with different GV1001 concentrations. Cell viability, proliferation, migration, and oxidative stress were determined by diverse molecular analyses. Results In the stroke model, GV1001 protected neural cells against IRI. The most effective dose of GV1001 was 60 μM/kg. The infarct volume on FLAIR 48 hours after MCAO compared to lesion volume on DWI showed a significantly smaller ratio in the GV1001-treated group. GV1001-treated rats exhibited better behavioral functions than the saline-treated rats. Treatment with GV1001 increased the viability, proliferation, and migration of the OGD/R-injured NSCs. Free radicals were significantly restored by treatment with GV1001. These neuroprotective effects of GV1001 have also been demonstrated in OGD/R-injured cortical neurons. Conclusions The results suggest that GV1001 has neuroprotective effects against IRI in NSCs, cortical neurons, and the rat brain. These effects are mediated through the induction of cellular proliferation, mitochondrial stabilization, and anti-apoptotic, anti-aging, and antioxidant effects.