The Productivity Debate of East Asia Revisited: A Stochastic Frontier Approach

This paper applies a stochastic frontier production model to the data from Penn World Table’s 49 countries over the period 1965-1990, to decompose total factor productivity growth into technical change and technical efficiency change. Empirical results show East Asian countries led the whole world in productivity growth, mainly because their technical efficiency gain was so much faster than that of other countries. East Asian countries also registered rapid technical change, which was comparable to that of the G6 countries after the late 1980s. The results provide evidence that negate the hypothesis that East Asian growth was mostly input-driven and unsustainable.East Asian Growth, stochastic frontier production model, total factor productivity, technical progress, technical efficiency

의상시착 학습:옷과 사람의 분리를 통해 옷의 상세 정보를 살려주는 시착방법

학위논문(석사) -- 서울대학교대학원 : 데이터사이언스대학원 데이터사이언스학과, 2023. 2. 이준석.Virtual try-on, fitting an image of a garment to an image of a person, has rapidly progressed recently. However, existing virtual try-on methods still struggle to faithfully represent various details of the clothes when worn. In this paper, we propose a simple yet effective method to better preserve details of the clothing and person by introducing an additional fitting step after geometric warping. This minimal modification helps to effectively learn disentangled representations of the clothing from the wearer. By disentangling these two major components for virtual try-on, we are able to preserve the wearer-agnostic structure and details of the clothing, and thus can fit a garment naturally to a variety of poses and body shapes. Moreover, we propose a novel evaluation framework applicable to any metric, to better reflect the semantics of clothes fitting. From extensive experiments, we empirically verify that the proposed method not only learns to disentangle clothing from the wearer, but also preserves details of the clothing on the try-on results.원하는 옷의 이미지를 사람의 이미지에 맞추어 입혀주는 가상 의류 시착 기술은 최근 빠르게 발전하고 있다. 하지만 현재 존재하는 가상 시착 방법들은 옷이 입혀졌을 때의 디테일을 잘 표현하지 못하고 있다. 본 논문에서, 나는 기하학적 변형 단계이후에 추가적인 피팅 단계를 추가함으로써 옷의 디테일을 보다 잘 살릴 수 있는 단순하지만 효과적인 방법을 제안한다. 이 최소한의 변화는 사람과 옷을 효과적으로 분리하는 방법을 소개하며, 이를 통해 옷의 디테일을 자연스럽고 효과적으로 합성할 수 있다. 또한, 본 논문에서 기존 측정방법에 적용할 수 있는 새로운 평가방법을 제안한다. 실험을 통해 본 논문에서 제시한 방법이 옷과 사람을 효과적으로 분리할 뿐만 아니라, 옷의 디테일을 자연스럽게 보존함을 보였다.Chapter 1. Introduction 3 Chapter 2. Related Work 5 Chapter 3. Preliminary 6 Chapter 4. The Proposed Method: DP-VTON 8 Chapter 5. Experiments 12 Chapter 6. Summary 19 Chapter 7. Supplementary materials 19 Bibliography 30 Abstract in Korean 35석

A Spatiotemporal analysis to identify Naturally Occurring Retirement Communities in Nebraska

This study aims to identify the geographic locations of “naturally occurring retirement communities (NORCs)” and whether there were spatiotemporal patterns of naturally occurring retirement communities in Nebraska for the time periods of 2000 to 2010, and to 2015. As the American population continues to age, older people generally prefer to live in their own homes for later years of life, instead of moving into assisted living. These demands have resulted in the increase of elderly populations who are “aging in place”. Nevertheless, there have been few spatiotemporal analyses about the distribution patterns of elderly households in terms of NORCs for the state of Nebraska. In this study, the entire area within the state’s boundaries was subdivided into block groups and the spatial statistics of demographic patterns were analyzed over time. For this study, U.S. Census data from 2000, 2010, and 2015 were aggregated by block groups which include the total number of households and proportion of households (owners/renters) in Nebraska. Three analyses were conducted on the data. First, the geovisualization method with ArcGIS 10.4 was used to visually investigate the distribution and changes of NORCs from 2000 to 2010, and to 2015. Second, Global Moran’s I was used to quantify the spatial relationship of NORCs in Nebraska. Third, various methods of spatial statistics were used to identify clusters between NORCs and other block groups: Local Moran’s and G-statistics. Over the past 15 years, the proportion of elderly households in Nebraska has steadily increased, and the rate of increase has risen sharply over the recent five years, as of 2015. As a result, the number of NORCs has also increased, and 47 of the total NORCs (57.3%) were classified as the aging in place type of NORCs. In addition, block groups with similar proportion of households have clustered spatially together or formed hot-spots. This study contributes to understanding the concept of NORCs relative to the residents “aging in place” and policy makers. Local government should take appropriate steps to prepare for the super aging society by rearranging and integrating given resources as much as possible. By taking full advantage of results of this study, the government should develop community-based policies to support the older residents aging in place. Because of the population density and proximity of older residents in NORCs, economies of scale are able to rethink how to organize and deliver services, giving the opportunity to make our communities better for those retired seniors. Advisor: Yunwoo Na

Alliance Networks, Corporate Investment, and Firm Valuation

This paper examines whether corporate alliance networks convey information about new investment opportunities. I hypothesize that firms located more centrally in their networks are exposed to greater information flows, which allows managers to rely less on their own stock prices as a source of information to make future investment decisions. Supporting this prediction, higher alliance network centrality leads to lower sensitivity of investment to stock prices. The impact is stronger for financially unconstrained firms, showing that financial constraints may limit firms’ ability to exploit their informational advantages from alliance networks. Additional tests exploiting quasi-exogenous changes in centrality due to indirect connections via alliance partners alleviate the endogeneity issue in alliance formation decision. The stock market reacts more positively to alliance announcements when new alliances are expected to provide greater informational benefits. Overall, my results show that alliance networks are conduits for value-enhancing information that affect corporate investment decision and valuation

Keys in the Clouds: Auditable Multi-device Access to Cryptographic Credentials

Personal cryptographic keys are the foundation of many secure services, but storing these keys securely is a challenge, especially if they are used from multiple devices. Storing keys in a centralized location, like an Internet-accessible server, raises serious security concerns (e.g. server compromise). Hardware-based Trusted Execution Environments (TEEs) are a well-known solution for protecting sensitive data in untrusted environments, and are now becoming available on commodity server platforms. Although the idea of protecting keys using a server-side TEE is straight-forward, in this paper we validate this approach and show that it enables new desirable functionality. We describe the design, implementation, and evaluation of a TEE-based Cloud Key Store (CKS), an online service for securely generating, storing, and using personal cryptographic keys. Using remote attestation, users receive strong assurance about the behaviour of the CKS, and can authenticate themselves using passwords while avoiding typical risks of password-based authentication like password theft or phishing. In addition, this design allows users to i) define policy-based access controls for keys; ii) delegate keys to other CKS users for a specified time and/or a limited number of uses; and iii) audit all key usages via a secure audit log. We have implemented a proof of concept CKS using Intel SGX and integrated this into GnuPG on Linux and OpenKeychain on Android. Our CKS implementation performs approximately 6,000 signature operations per second on a single desktop PC. The latency is in the same order of magnitude as using locally-stored keys, and 20x faster than smart cards.Comment: Extended version of a paper to appear in the 3rd Workshop on Security, Privacy, and Identity Management in the Cloud (SECPID) 201