The origin, evolution, and application of the megapolitan area concept

Robert E. Lang,임재원,Karen A. Danielsen 서울시립대학교 도시과학연구원 2020 도시과학국제저널 Vol.24 No.1

The article explores the origin and evolution of the ‘megapolitan concept', the idea of a super-sized region that began in 1961 in Jean Gottmann's ‘megalopolis,' which he developed to explain large-scale urbanization in the Northeastern U.S. Jerome Picard, a researcher at the Urban Land Institute took up the megalopolis idea in 1967 and applied it to the entire U.S. and projected large-scale urban growth to 2000. The Regional Plan Association (RPA) also applied the megalopolis concept to The Second Regional Plan for New York in 1968. Lang in 2000s, then working with his colleagues at Virginia Tech developed the megapolitan concept and definition-in part to differential the concept from work being done by the University of Pennsylvania for RPA. Lang defined ‘megapolitan clusters’ as multiple megapolitan areas that are networked either by commuting, logistics, or dense air links, but where there is no more than three times the distance used to define a Megapolitan Area between anchor metropolitan areas at their furthest distance. The recent evolution of megapolitan area and megapolitan cluster concepts by Lang and the colleagues is applied to a series of projects, including ‘Sun Corridor’ in 2006 (Phoenix-Tucson) and the Southwest Triangle (SoCal-Sun Corridor-Las Vegas) in 2014. The article ends with the future application of megapolitan area concept in the rapidly growing Southwest Triangle megapolitan cluster.

Anthropogenic Climate Change

lang G. Bryden,Peter K. J. Robertson,Detlef W. Bahnemann 한국에너지기후변화학회 2006 에너지기후변화학회지 Vol.1 No.1

Mathematical Modeling of Zombie Infection for Mathematics Courses: Using ODE`s, Sage, and Video Games

( Lang Victoria Lee ),( Sang Gu ) 한국수학교육학회 2014 뉴스레터 Vol.30 No.5

The notion of the reanimated dead (i.e. "zombies") has a strong historical basis that has fascinated the general public for centuries. The zombie still remains a popular figure in entertainment media; specifically, in video games. Expanding upon the well-known S.I.R. epidemiological model. we first examine basic models for zombie infection first introduced by Munz, Hudea, Imad & Smith? (2009). Specifically, we modify these models to be visualized online via Sage, an open-source mathematics software based in the Python programming language, that allows for direct user interaction. We then focus on viewing mathematically "realistic" population trajectories for the different classes of zombies from Left 4 Dead<http://www.14d.com/blog/> Valve Corporation`` s immensely popular video game series that revolves around human players surviving a pandemic of zombie infection. The respective strengths, weaknesses, and dynamics of each zombie class are mathematically established, and all outcomes are numerically realized with online Sage tools. These models are available for viewing, manipulation, and use in a mobile environment at <http://matrix. skku.ac.kr/2014-Zombie-Model>and, thus, can serve as an effective and exciting academic tool for the interested student of any college-level Ordinary Differential Equations course.

Infective Endocarditis : Current Concepts in Treatment

Lang, S.D.R. Medical Publications Korea 1977 Medical Progress Vol.4 No.11

A New Method of Gelatin Modified Collagen and Viscoelastic Study of Gelatin-Collagen Composite Hydrogel

Lang He,Sheng Li,Chengzhi Xu,Benmei Wei,Juntao Zhang,Yuling Xu,Beirong Zhu,Yang Cao,Xilin Wu,Zhijin Xiong,Rongrui Huang,Jian Yang,Haibo Wang 한국고분자학회 2020 Macromolecular Research Vol.28 No.9

Pure collagen materials are expensive with poor mechanical properties, which need modifications in most cases. As the degradation product of collagen, gelatin is cheap, degradable and biocompatible, but few literatures have reported the research about gelatin-collagen composite materials. This is because gelatin and collagen have different soluble temperatures—gelatin is soluble in hot water (≥30 oC) and swells in cold water. However, a low temperature (2-10 oC) is required to prepare and store collagen solution, and neutral collagen solution denatures quickly above the room temperature. In this study, gelatin was ground into powders and swelled in neutral bovine tendon pepsin-soluble collagen solution (BPSC) to form a homogeneous gelatin-collagen mixture, in light of the swelling characteristics of gelatin in cold water. The assembly properties and gel properties of this composite material were further studied. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) test results showed that the bovine tendon collagen had typical type-I collagen structural characterizations with two α chains of about 100 kDa and one β chain of about 200 kDa; while the SDS-PAGE pattern of gelatin displayed bands continuously distributed from 30 to 200 kDa. Amino acid composition analysis test indicated that the content of polar amino acids and the sum of acidic and base amino acids for gelatin were higher than that of BPSC. Studies on gel properties demonstrated that gelatin-collagen mixed solution had collagenlike assembly characteristics and assembly kinetics. The moduli of the assembled gel at 35 oC were equivalent to that of pure bovine tendon collagen system; moreover, the system moduli didn’t change with time with elastic moduli (G') of about 40 Pa. However, at 25 oC, the moduli of gelatin-collagen composite hydrogel increased with the extension of time, its G' increased about 18 times within 8 h, and the ratio of elastic modulus to viscous modulus (G'') increased 4.6 times, showing a significant aging effect of structural strength. Meanwhile, the mechanical strength of the composite hydrogel was also regulated by temperature—the gel was highly elastic (G'≈3,000 Pa, G'>>G'') at a low temperature (5 oC); as the temperature rose, the system moduli gradually decreased and the elastic gel transformed into waterlike fluid at 50 oC little by little. What’s more, gelatin-collagen composite hydrogel also had reversible sol-gel performances and self-healing capability similar to the gelatin hydrogel. This novel preparation method for preparing composite materials and the resultant composite hydrogel are expected to be used in the fields of natural food gels, injectable hydrogels, cell scaffolds, drug sustained-release materials and so on, and improve and promote the processing performances, price and large-scale production of collagen-based materials.

Surface Functionalization of Graphene Oxide via Activators Regenerated by Electron Transfer for Atom Transfer Radical Polymerization and Its Effect on the Performance of Poly(lactic acid)

Lang Zheng,Weijun Zhen 한국고분자학회 2018 폴리머 Vol.42 No.4

An improved Hummers method was used to prepare graphene oxide (GO). Then, the orthogonal experiment design methods were used to select the optimum conditions of preparation for graphene oxide-polymethyl methacrylate (GO-PMMA) via activators regenerated by electron transfer for atom transfer radical polymerization (AGET-ATRP). The optimum preparation conditions were determined by orthogonal tests. Furthermore, poly(lactic acid) (PLA)/GO-PMMA nanocomposites were prepared by melt blending to improve the comprehensive performance of PLA. Analysis results indicated that methyl methacrylate (MMA) was successfully grafted onto GO, and the addition of 0.3 wt% of GO-PMMA increased the tensile strength, elongation at break, and impact strength of PLA/GO-PMMA nanocomposites by 7.82, 40.66, and 50.62%, respectively, compared with PLA. Moreover, GO-PMMA eliminated the cold crystallization of PLA matrix and improved the crystallinity of PLA by 27.55%. In all, this study provided an effective and feasible method for improving the comprehensive performance of PLA.

New Information About Prostate-Specific Antigen and the Paradoxes of Prostate Cancer

Lange, Paul H. MediMedia Korea 1995 JAMA-Korea Vol.10 No.6

Der arge Weg der Erkenntnis : Zur Analysedes "Goya"-Romans von Lion Feuchtwanger auf dem Hintergrund seiner Biographie 리온 포이히트봥어의 생애를 배경으로 한 소설 "고야(Goya)"의 분석

Lange, Dietmar 단국대학교 1986 論文集 Vol.20 No.-

한국에는 리온 포이히트봥어(Lion Feuchtwanger)의 작품들이 아직 잘 알려져 있지 않는 편이다. 이 논문에서 논의된 그의 소설 「고야 또는 인식의 험난한 길」은 그의 전형적인 역사소설일 뿐만 아니라 그의 자서전적 요소들이 많이 내포되어 있으므로 제한된 범위에서나마 그의 인간과 작품을 이해하는 데 도움이 될 것이다. 뮨헨 출신의 유태인인 포이히트봥어는 일찍부터 연극 및 문예 비평과 더불어 희곡과 소설들을 쓰기 시작했다. 그러나 뮨헨의 떠돌이 문인에서 시작하여 독일 망명문학을 대표하는 세계적인 작가가 된다는 것은 멀고도 힘든 길이다. 포이히트봥어의 작품들 중에서는 역시 역사소설들이 큰 비중을 차지한다고 말할 수 있을 것이다. 이 논문에서 논의되고 있는 포이히트봥어의 소설 「고야 또는 인식의 험난한 길」의 주인공 고야(Goya)는 하층 사회에서 태어나 스페인의 가장 이름난 화가가 된 사람이다. 그러나 포이히트봥어의 소설에서는 고야가 궁정화가로서 이미 큰 성공을 거둔 이후의 그의 내면세계가 그려져 있다. 고야는 본의 아니게 정치에 말려들어 까이에따나 데 알바 공작부인과의 사랑과 증오의 감정이 뒤섞인 관계로 고통을 당하게 되고, 사랑하는 딸을 잃게 되고, 종교재판의 위협을 받게 되는 등 온갖 정신적 좌절을 경험하게 될 뿐만 아니라 청력까지 잃게 된다. 하지만 이 모든 어려움과 싸우는 동안 그의 시력은 더욱 날카로와져 그 시대를 풍미하던 의고전주의를 극복함으로써 인간의 본질을 꿰뚫어 보고 그것을 그릴 수 있게 된다. 고야는 그의 <관념들>을 형상화함으로써 스페인의 중세적 상황을 비유적으로 그릴 수 있었고, 그 결과 그의 그림을 보는 사람은 그러한 중세적 상황의 사악함과 그 극복의 필요성을 인식할 수 있게 되는 것이다. 왜냐하면 그의 그림에 나타난 <관념들>은 누가나 이해할 수 있는 世界語이기 때문이다. 소설「고야 」는 발전소설이다. 그러나 그 주인공은 직선적으로 발전하거나 이상적인 인간으로 승화되는 것이 아니라 내면적인 발전을 거듭하면서도 끝까지 모순투성이의 인간으로 남는다. 이 소설은 주인공의 내면적 갈등과 18세기 말 스페인의 절망적인 사회상을 强弱格(Trocha¨us)의 反語的인 사용과 視角 및 場面들의 다양한 변화를 통하여 생생하게 그리고 있다는 점에서 전형적인 20세기 유럽 소설이라고 할 수 있을 것이다. 무엇보다도 소설의 주인공이 사회적인 문제들에 말려들게 되고, 이에 대한 내면적 성향 과정을 통하여 예술적으로 완숙한 경지에 이른다는 것은 1차대전 이후에 씌어진 소설들의 공동광장(Topos)의 하나이기 때문이다. 그런 의미에서 이 소설의 주인공이 걷는 길은 망명작가 포이히트봥어 자신이 걸어간 길이었다. 또한〈이성을 위하여--우매와 폭력을 반대하여〉라는 포이히트봥어 작품들의 주도동기(Leitmotiv)가 이 소설에서 만큼 선명하게 부각된 곳은 없을 것이다.

Characterization of Two-Dimensional Transition Metal Dichalcogenides in the Scanning Electron Microscope Using Energy Dispersive X-ray Spectrometry, Electron Backscatter Diffraction, and Atomic Force Microscopy

Lang, Christian,Hiscock, Matthew,Larsen, Kim,Moffat, Jonathan,Sundaram, Ravi Korean Society of Microscopy 2015 Applied microscopy Vol.20 No.1

Here we show how by processing energy dispersive X-ray spectrometry (EDS) data obtained using highly sensitive, new generation EDS detectors in the AZtec LayerProbe software we can obtain data of sufficiently high quality to non-destructively measure the number of layers in two-dimensional (2D) $MoS_2$ and $MoS_2/WSe_2$ and thereby enable the characterization of working devices based on 2D materials. We compare the thickness measurements with EDS to results from atomic force microscopy measurements. We also show how we can use electron backscatter diffraction (EBSD) to address fabrication challenges of 2D materials. Results from EBSD analysis of individual flakes of exfoliated $MoS_2$ obtained using the Nordlys Nano detector are shown to aid a better understanding of the exfoliation process which is still widely used to produce 2D materials for research purposes.

N-Step Sliding Recursion Formula of Variance and Its Implementation

Lang Yu,Gang He,Ahmad Khwaja Mutahir 한국정보처리학회 2020 Journal of information processing systems Vol.16 No.4

The degree of dispersion of a random variable can be described by the variance, which reflects the distance of the random variable from its mean. However, the time complexity of the traditional variance calculation algorithm is O(n), which results from full calculation of all samples. When the number of samples increases oron the occasion of high speed signal processing, algorithms with O(n) time complexity will cost huge amount of time and that may results in performance degradation of the whole system. A novel multistep recursive algorithm for variance calculation of the timevarying data series with O(1) time complexity (constant time) is proposed in this paper. Numerical simulation and experiments of the algorithm is presented and the results demonstrate that the proposed multistep recursive algorithm can effectively decrease computing time and hence significantly improve the variance calculation efficiency for timevarying data, which demonstrates the potential value for timeconsumption data analysis or high speed signal processing.