서울시 녹지 연결망의 시계열 분석 및 정책적 함의

장병우(Chang, Byungwoo),박신영(Park, Sinyoung),정진아(Jeong, Jina),강완모(Kang, Wanmo) 한국지적정보학회 2021 한국지적정보학회지 Vol.23 No.1

본 연구는 그래프 이론을 적용하여 지난 35년(1984~2019년)간의 서울시 녹지 연결망의 변화를 다각적으로 비교·분석하고 정책적 함의를 제시하고자 하였다. Landsat 위성영상의 다중시기 정규식생지수를 통해 녹지 패치를 도출하고, 다양한 공간규모에서 직선거리와 최소비용경로에 따른 패치 및 비-패치 기반의 연결망 분석 기법을 적용했다. 연구 결과, 1984년부터 2019년까지 녹지 연결성이 회복되고 향상되었음을 정량적으로 확인하였고, 연결망 보전·관리에 있어서 중요한 녹지를 도출하였다. 비-패치 기반의 연결망 모형을 통해 시간 흐름에 따른 서울시의 핵심 녹지축 변화를 추적하여 북악산에서 남산, 국립서울현충원, 관악산으로 이어지는 녹지축의 회복을 확인할 수 있었다. 용산공원 신규 조성에 따른 연결성 기여도 평가 결과, 녹지 면적 증가 대비 연결성 증진 효과가 매우 높은 것으로 모의되었다. 또한, 용산공원은 서울시의 핵심 녹지축을 강화시키고, 확장시킬 수 있는 녹지로도 확인되었다. 연구 결과들은 서울시 도시생태계와 시민들의 삶의 질을 높일 수 있는 생활권 녹지공간 확충과 지속 가능한 도시기본계획 체계화 및 관리계획 수립을 위한 정책결정 과정에서 많은 기여를 할 수 있을 것으로 기대된다. We analyzed the temporal changes of green space network in Seoul from 1984 to 2019 using graph theory to suggest policy implications. For the analysis, we extracted green space patches using Landsat NDVI (Normalized Difference Vegetation Index) time-series data. Patch- and non-patch-based network analyses were applied using Euclidean distance and least-cost distance at multi-spatial scales. The patch-based network analysis confirmed the notable recovery and improvement of the network connectivity during the study period. We identified the important green spaces that are pivotal in preserving and managing the green space network. In addition, based on the non-patch-based network analysis, we found the recovery trend of main green corridors connecting the area from north to south. The establishment of Yongsan Park contributed greatly to the improve the connectivity, compared to the increased area of the green space. The result also showed that Yongsan Park can strengthen and expand the green corridor. We hope our research provides useful information for policymakers to expand neighborhood green spaces and develop sustainable urban master plans.

Optimum Morphology of Mixed-Olivine Mesocrystals for a Li-Ion Battery

Park, Kimin,Kim, Jaewon,Wi, Sungun,Lee, Sangheon,Hwang, Taehyun,Kim, Jaewook,Kang, Joonhyeon,Choi, Joon-Phil,Nam, Seunghoon,Park, Byungwoo American Chemical Society 2018 Inorganic Chemistry Vol.57 No.10

<P>In this present work, we report on the synthesis of micron-sized LiMn<SUB>0.8</SUB>Fe<SUB>0.2</SUB>PO<SUB>4</SUB> (LMFP) mesocrystals via a solvothermal method with varying pH and precursor ratios. The morphologies of resultant LMFP secondary particles are classified into two major classes, flakes and ellipsoids, both of which are featured by the mesocrystalline aggregates where the primary particles constituting LMFP secondary particles are crystallographically aligned. Assessment of the battery performance reveals that the flake-shaped LMFP mesocrystals exhibit a specific capacity and rate capability superior to those of other mesocrystals. The origin of the enhanced electrochemical performance is investigated in terms of primary particle size, pore structure, antisite-defect concentration, and secondary particle shape. It is shown that the shape of the secondary particle has just as much of a significant effect on the battery performance as the crystallite size and antisite defects do. We believe that this work provides a rule of design for electrochemically favorable meso/nanostructures, which is of great potential for improving battery performance by tuning the morphology of particles on multilength scales.</P><P>Micron-sized LiMn<SUB>0.8</SUB>Fe<SUB>0.2</SUB>PO<SUB>4</SUB> mesocrystals having various morphologies were facilely synthesized via a solvothermal method. The origin of the different electrochemical performances of the mesocrystals was investigated in terms of primary particle size, pore structure, antisite-defect concentration, and secondary particle shape. We believe that this work can provide a rule of design for the electrochemically favorable meso/nanostructures, which is of great potential for improving battery performance.</P> [FIG OMISSION]</BR>

The effects of ruthenium-oxidation states on Ru dissolution in PtRu thin-film electrodes

Park, Yejun,Lee, Byungjoo,Kim, Chunjoong,Oh, Yuhong,Nam, Seunghoon,Park, Byungwoo Cambridge University Press (Materials Research Soc 2009 Journal of materials research Vol.24 No.9

<P>The effects of ruthenium (Ru)-oxidation states were investigated on Ru dissolution from PtRu thin-film electrodes, with the 200 cycles between 0.4 and 1.05 V (versus normal hydrogen electrode). The Ru-oxidation states of the PtRu thin films were systematically modified by an anodic (oxidation) treatment. The anodic-treated PtRu electrodes, whose methanol-oxidation activity was similar to untreated electrodes before the 200 cycles, showed a remarkable decrease in methanol oxidation after the cycles, because of the Ru dissolution from the PtRu surface. The results suggest that the Ru-oxide species are the origin of Ru dissolution in the PtRu alloy.</P>

Thin Film Fabrications : SYNTHESIS OF METASTABLE CARBON - SILICON - NITROGEN COMPOUNDS

Byungwoo Park 대한금속재료학회 ( 구 대한금속학회 ) 1995 Advanced Material and Processing Vol.1 No.-

Effects of iron-phosphate coating on Ru dissolution in the PtRu thin-film electrodes

Park, Yejun,Lee, Byungjoo,Kim, Chunjoong,Kim, Jongmin,Park, Byungwoo Cambridge University Press (Materials Research Soc 2009 Journal of materials research Vol.24 No.1

<P>The effects of FePO4 nanoscale coating on PtRu thin films were investigated on the block of Ru crossover. Ru dissolution was examined by the accelerated-potential cycles between 0.4 and 1.05 V. The results showed that Ru dissolution from FePO4-coated PtRu surface was inevitable due to the direct contact between the PtRu surface and aqueous electrolyte. However, the FePO4 coating layer on PtRu thin-film electrodes effectively retained the dissolved Ru species, thus preventing the dissolved Ru species from diffusing into the electrolyte. Moreover, the retained Ru species within the FePO4-coating layer were redeposited onto the PtRu surface during the cycling in the fresh electrolyte.</P>

저품질 지문 영상의 배경 분리 알고리즘 개선

박정호,송종관,윤병우 경성대학교 공학기술연구소 2003 공학기술연구지 Vol.S2 No.1

In fingerprint verification and identification, fingerprint and background region should be segmented. For this purpose, most systems obtain variance of brightness of X and Y direction using Sobel mask. To decide if given local region is background or not, the variance is compared with a certain threshold. Although this method is simple, most fingerprint image does not separated with two region of fingerprint and background region. In this paper, we presented a new segmentation algorithm based on run-length connectivity analysis. For a given binary image after thresholding, suggested algorithm calculates RL of X and Y direction. Until the given image is segmented to two regions, small run region is successively inverted. Experimental result show that this algorithm effectively separates fingerprint region and background region.

Methodology for Predicting the Durability of Aged Tire Sidewall Under Actual Driving Conditions

Byungwoo Moon,Jongmin Lee,Seongrae Kim,Soo Park,Chang-Sung Seok 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.8

This article presents new rational methodology to predict the life for actual driving condition of an aged tire sidewall, and how to judge durability for fatigue life. Generally, life prediction methods in previous studies have presented simple lifetime under normal rolling state using a strain, stress, and virgin property, but this paper used an actual driving pattern, strain energy density and aged rubber property to predict accelerated test results. For this purpose, steady-state rolling analysis and fatigue test are applied to predict the durability life of tire under actual driving conditions. A finite element model of a tire which can replicate the aged tire sidewall was generated, and the driving distance of the tire was calculated using the dynamic rolling radius. The rate of acceleration, deceleration, and cruising is calculated by applying the driving patterns of peak hours of major cities where cruising time is low due to high traffic volume. This paper contains all procedure and methodology for predicting the durability of aged tire sidewall such as method to predict life, finite element analysis, and application of aging rubber.

Energy-Density Enhancement of Carbon-Nanotube-Based Supercapacitors with Redox Couple in Organic Electrolyte

Park, Jinwoo,Kim, Byungwoo,Yoo, Young-Eun,Chung, Haegeun,Kim, Woong American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.22

<P>We demonstrate for the first time that the incorporation of a redox-active molecule in an organic electrolyte can increase the cell voltage of a supercapacitor. The redox molecule also contributes to increasing the cell capacitance by a faradaic redox reaction, and therefore the energy density of the supercapacitor can be significantly increased. More specifically, the addition of redox-active decamethylferrocene in an organic electrolyte results in an approximately 27-fold increase in the energy density of carbon-nanotube-based supercapacitors. The resulting high energy density (36.8 Wh/kg) stems from the increased cell voltage (1.1 V → 2.1 V) and cell capacitance (8.3 F/g → 61.3 F/g) resulting from decamethylferrocene addition. We found that the voltage increase is associated with the potential of the redox species relative to the electrochemical stability window of the supporting electrolyte. These results will be useful in identifying new electrolytes for high-energy-density supercapacitors.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-22/am506258s/production/images/medium/am-2014-06258s_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am506258s'>ACS Electronic Supporting Info</A></P>

A NEW ENSEMBLE LEARNING ALGORITHM USING REGIONAL CLASSIFIERS

LEE, BYUNGWOO,CHOI, SUNGHA,OH, BYONGHWA,YANG, JIHOON,PARK, SUNGYONG World Scientific 2013 International journal on artificial intelligence t Vol.22 No.4

Transmittance of long-wavelength infrared surface plasmon by two dimensional Ag hole arrays

Hyunbin PARK,Ha Sul KIM,Byungwoo LEE 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8