Compact UWB Antenna With I-Shaped Band-Notch Parasitic Element for Laptop Applications

A compact ultrawideband (UWB) antenna with a band-notch function is proposed for laptop applications. The band-notch function is realized by a half-wavelength parasitic element printed on the rear side of the substrate. The impedance bandwidth (VSWR \u3c 2) of the antenna is 3.1 ~ 11.4 GHz (114%) with a notched frequency from 5.05 to 5.90 GHz. The antenna has a fairly good omnidirectional pattern, and the average gain is -3.0 ~ -1.2 dBi over the UWB frequency band except for the notched frequency band. The performance of the proposed antenna is confirmed by simulation and measurement results

External Ventricular Drainage before Endovascular Treatment in Patients with Aneurysmal Subarachnoid Hemorrhage in Acute Period: Its Relation to Hemorrhagic Complications

Purpose The purpose of this study was to report the authors’ experience with external ventricular drainage (EVD) before endovascular treatment (EVT) in patients with acute aneurysmal subarachnoid hemorrhage (aSAH) and to investigate its relation to hemorrhagic complications.Materials and Methods Between March 2010 and December 2017, a total of 122 patients were recruited who had an aSAH, underwent EVT to secure the ruptured aneurysm, and had EVD performed within 72 hours of rupture. The pre-embo EVD group (n=67) comprised patients who underwent EVD before EVT, and the post-embo EVD group (n=55) comprised those who underwent EVD after EVT. Results Overall, EVD-related hemorrhage occurred in 18 patients (14.8%): six (8.9%) in the pre-embo EVD group and 12 (21.8%) in the post-embo EVD group (P=0.065). No rebleeding occurred between EVD and EVT in the pre-embo EVD group. Clinical outcomes at discharge did not differ significantly between groups (P=0.384). At discharge, the final modified Rankin Scale score in patients who experienced pre-embo rebleeding was better in the pre-embo EVD group than in the post-embo EVD group (P=0.041). Current use of an antiplatelet agent or anticoagulant on admission (odds ratio [OR], 2.928; 95% confidence interval [CI], 1.234–7.439; P=0.042) and stent use (OR, 2.430; 95% CI, 1.524–7.613; P=0.047) remained independent risk factors for EVD-related hemorrhagic complications. Conclusion EVD before EVT in patients with aSAH in acute period did not increase the rate of rebleeding as well as EVD-related hemorrhagic complications. Thus, performing EVD before EVT may be beneficial by normalizing increased intracranial pressure. Especially in patients with rebleeding before the ruptured aneurysm is secured, pre-embo EVD may improve clinical outcomes at discharge

Gravitational-wave Electromagnetic Counterpart Korean Observatory (GECKO): GECKO Follow-up Observation of GW190425

One of the keys to the success of multimessenger astronomy is the rapid identification of the electromagnetic wave counterpart, kilonova (KN), of the gravitational-wave (GW) event. Despite its importance, it is hard to find a KN associated with a GW event, due to a poorly constrained GW localization map and numerous signals that could be confused as a KN. Here, we present the Gravitational-wave Electromagnetic wave Counterpart Korean Observatory (GECKO) project, the GECKO observation of GW190425, and prospects of GECKO in the fourth observing run (O4) of the GW detectors. We outline our follow-up observation strategies during O3. In particular, we describe our galaxy-targeted observation criteria that prioritize based on galaxy properties. Armed with this strategy, we performed an optical and/or near-infrared follow-up observation of GW190425, the first binary neutron star merger event during the O3 run. Despite a vast localization area of 7460 deg^2, we observed 621 host galaxy candidates, corresponding to 29.5% of the scores we assigned, with most of them observed within the first 3 days of the GW event. Ten transients were discovered during this search, including a new transient with a host galaxy. No plausible KN was found, but we were still able to constrain the properties of potential KNe using upper limits. The GECKO observation demonstrates that GECKO can possibly uncover a GW170817-like KN at a distance less than 200 Mpc if the localization area is of the order of hundreds of square degrees, providing a bright prospect for the identification of GW electromagnetic wave counterparts during the O4 run.Comment: 35 pages, 19 figures Accepted for publication in Ap

일본 EC시장에서 아마존의 성공요인

학위논문(석사)--서울대학교 대학원 :국제대학원 국제학과(국제지역학전공),2020. 2. 김현철.Since the dot-com bubble during late 1990s, E-commerce emerged as an industry which has grown enormously during the last two decades around the globe. Internet enabled people to connect each other through the cyber world and eventually led to various Internet oriented companies to expand. Japan was one of the countries that was affected by that bubble. One of the first mover of online retail industry in Japan, Rakuten Ichiba, started its own business in May of 1997. In the year of 2000 Rakuten went on public through on IPO on the OTC market, which is currently TSE JASDAQ market. After the IPO, in that same year, in November 11th, Amazon opened its Japanese branch. Comparing those two E-commerce companies in the year of 2018, the revenue of Amazon Japan has surpassed the revenue of Rakuten. Numerous medias are focusing the success of Amazon in Japanese market, which is usually challenging obstacles for foreign companies to succeed in Japan, and how Amazon was able to capture Japanese domestic consumers. The paper will examine how Amazon Japan successfully maintained and survived in Japanese E-commerce market through Last-movers Advantages, and how Rakuten could not capture its First-movers Advantages. Consequentially, the paper will figure out the key success factors of Amazon Japan and adduce some insights to foreign companies how to enter Japanese market successfully like Amazon did.1990년대 후반의 닷컴 버블 이후로 부터, 전자상거래 (e-commerce)는 최근 20년간 전세계적으로 빠른 속도로 성장하고 있다. 인터넷은 사람과 사람을 온라인상으로 연결 시켜주어, 결국엔 많은 인터넷 중심으로 사업을 이끄는 신규 회사들이 많이 탄생 하였다. 일본도 닷컴 버블로 인하여 영향을 받은 나라들 중에 하나였다. 일본 온라인 유통업의 선발주자이었던 라쿠텐은 1997년 5월 회사가 설립 되었다. 2000년에는, 라쿠텐은 OTC마켓에서 IPO를 함으로써 상장을 하였다. 그 같은 해의 11월에, 아마존이 일본에 자회사를 설립하였다. 지금 최근 2018년도 기점으로 이 두회사를 비교해보면, 아마존재팬의 매출이 라쿠텐의 매출을 능가하였다. 다양한 언론과 미디어에서는 어떻게 해외기업이 진출하기 어려운 시장중 하나인 일본시장을 아마존이 성공적으로 진출 했는지를 눈여겨 보고있고, 어떻게 일본 국내 소비자들의 마음을 잡을 수 있던 원인에 대하여 궁금해한다. 이번 연구에서는 아마존 재팬이 어떻게 후발우위를 지키면서 라쿠텐을 제치고 일본 EC시장에서 성공적으로 자리를 잡을 수 있었는지에 대하여 알아 보려고한다. 결과적으로 아마존재팬의 성공요인에 대하여 알아보고 선발우위성을 가지고 있는 기업들을 어떻게 제칠수 있는지 제시한다.Introduction pg. 1 Literature Review pg.11 Research Question pg.21 Case Study pg.24 Conclusion & Limitations pg.40 Bibliography pg.44 논문초록 pg.50Maste

The Impact of CSR on Corporate Value of Restaurant Businesses Using Triple Bottom Line Theory

The main goal of this study was to investigate the association between corporate social responsibility (CSR) and the value of restaurant firms by employing triple bottom line theory, a framework for a business model of sustainable development focusing on profit, environment, and people rather than just maximizing profit. Even though triple bottom line has been a common theoretical foundation in the CSR area, there is sparse literature on the theory in the context of CSR in the restaurant domain. Data regarding CSR dimensions and market-to-book value from 32 publicly traded restaurant firms in the US stock market for the period 1999–2012 were gathered, and panel data analysis methods of ordinary least square, one-way fixed effect, and time series feasible generalized least square were employed. The results revealed that economic CSR enhanced restaurant value, whereas environmental CSR diminished the value. The theoretical contribution of this study is that it will broaden the scope of triple bottom line theory. The results of the study will help restaurant administrators determine CSR policy