The epidemiology of COVID-19 cases and the successful containment strategy in Hong Kong-January to May 2020

BACKGROUND: Hong Kong, a Special Administrative Region of China, recorded its first confirmed coronavirus disease 2019 (COVID-19) case on 23 January 2020. We reviewed the case epidemiology and the various public health measures implemented from January to May 2020. METHODS: The epidemiological and clinical characteristics of the cases recorded in different phases of the epidemic were described and compared, and the effectiveness of the public health measures implemented were reviewed using the changes in the daily number of confirmed cases and the interval from symptom onset to hospital admission. RESULTS: Between January and May 2020, 1084 confirmed COVID-19 cases were reported, about 70% of which had a history of travel during the incubation period. The case fatality ratio was 0.4%. The local epidemic progressed through four phases: (1) preparedness and imported infection from mainland China, (2) local transmission, (3) imported infection from overseas countries associated with local transmission, and (4) controlled imported infection with limited local transmission, with an eventual reduction of the daily case number and minimization of the onset-to-admission interval. Various public health measures, including enhanced surveillance, border control, and social distancing, were introduced in phases in response to the prevailing local and global situations. DISCUSSION: The overall containment strategy in Hong Kong led to a stabilization of the number of cases and the absence of a community-wide outbreak during the 4.5 m after the first case was reported. This strategy of containment might serve as an example for future planning of preparedness and response against novel infectious agents

Understanding what verb phrases and adjective phrases have in common: Evidence from Mandarin alternations

The goal of the present study is to investigates the relation between syntax and semantics. To this end, this study looks at the Mandarin verbal alternation (ba-construction and SVO order) and comparative alternation (transitive comparative and bi-comparative). In both alternations, it is observed that one variant is selective to its complement predicates. This study proposes that the selectivity of ba-construction and the transitive comparative in syntax comes from the semantic boundedness. Specifically, the selective functional head (little-v0 or Deg0, respectively) is hypothesized to require its complements to be bounded, which can be encoded in various ways, such as secondary predicates or perfective marking in the verbal domain and closed scale adjectives or measure phrase in the adjectival domain. On the other hand, the SVO order and the bi-comparative are hypothesized to be unselective and compatible with all types of predicates. A two-part experimental study was conducted to test the hypothesis. The judgment task elicits informants\u27 acceptance of the alternations in a 7-point Likert scale. The comprehension task, in which participants indicate their interpretation of sentences by choosing a picture, shows that participants are sensitive to the presence of the bounded markers tested in the experiment. The results from the acceptability judgment task confirmed the hypothesis that a variant (ba and transitive comparative) in each alternation selects only bounded predicates, whereas the other variant (SVO order and bi-comparative) is unselective with regard to boundedness, as evidenced by similar acceptability ratings across the different configurations with regard to boundedness. The results have two implications. First, boundedness shows that semantic factors may affect syntactic selection. This, in turn, suggests a tight mapping between syntax and semantics. Specifically, this study argues that boundedness is an example of how formal feature(s) of a functional category may relate to semantic behaviors. Second, the verbal and adjectival domains shows striking parallels in their syntax and semantics. The functional categories (v 0 and Deg0) and their complements are similar in both their syntax and semantics. The present study contributes by providing a unified analysis for the cross-categorial behaviors

The Persistence of Smoke: Opera in One Act, Libretto by John Justice

<p><italic>The Persistence of Smoke</italic> is a documentary opera. The libretto is based on interviews with various individuals related to the former Liggett and Myers Tobacco Company headquarters in Durham, North Carolina.</p><p>The cigarette industry once dominated Durham, but saw its decline in the 1990s as the link between cancer and smoking became increasingly clear. The American Tobacco Company and the Liggett and Myers Tobacco Company were once the biggest cigarette manufacturers in the city. As these companies left Durham, their factories and tobacco warehouses first sat vacant, but were gradually preserved and transformed into new spaces for offices, apartments and restaurants.</p><p>This project focused on the former Liggett and Myers headquarters along Main Street, a collection of buildings now known as "West Village". I interviewed current and former Durham residents who had a connection with these buildings, including local business representatives, community leaders, former Liggett employees, historians, current residents in the downtown area, municipal urban planners, journalists, and an architect. These interviews were given to local playwright John Justice, who created a libretto based on the themes that emerged.</p><p>The opera's story focuses on Kevin, an architect about to unveil his visionary master plan for redeveloping several defunct cigarette factories in an unnamed city. As Kevin leaves his newly renovated apartment for the press conference, he is confronted by his estranged father Curtis, a former cigarette worker who desperately wants to reconcile and reconnect, deliriously recalling the glory days of tobacco and the money that followed.</p>Dissertatio

A New Motion Vector Composition Algorithm for H.264 Multiple Reference Frame Motion Estimation

Multiple reference frame motion estimation (MRF-ME) is an important tool in H.264 to improve coding efficiency. However, it penalizes the encoder in computational complexity. When the number of reference frames increases, the required computation expands proportionally. Therefore, various motion vector composition algorithms have been proposed to reduce the computational complexity of the encoder. However, it is found that they only perform well in a limited range of reference frames. In this paper, a new composition algorithm is proposed to compose a resultant motion vector from a set of candidate motion vectors. The proposed algorithm is especially suited for temporally remote reference frames in MRF-ME. Compared with existing algorithms, experimental results show that the new algorithm can deliver a remarkable improvement on the rate-distortion performance.APSIPA ASC 2009: Asia-Pacific Signal and Information Processing Association, 2009 Annual Summit and Conference. 4-7 October 2009. Sapporo, Japan. Poster session: Image, Video, and Multimedia Signal Processing 2 (6 October 2009)

Depth-projected determination for adaptive search range in motion estimation for HEVC

50th IEEE International Symposium on Circuits and Systems, ISCAS 2017, Baltimore, U.S.A., 28-31 May 2017High Efficient Video Coding (HEVC) improves coding efficiency but suffers from high computational complexity due to its quad-tree partitioning structure in motion estimation (ME). In recent development of 3D video technology, depth map from the 3D video provides an intimation of the objects' distance from the projected screen in a 3D scene, which inspires the authors to explore the adaptive search range determination for complexity reduction in HEVC. The proposed algorithm exploits the high temporal correlation between the depth map and the motion in texture. By utilizing this correlation and the potential impact of 3D-to-2D projection, a depth/motion relationship is built for a tailor-made search range with a depth-projected scale factor to skip unnecessary search points in ME. Besides, the proposed ASR algorithm can work well with other fast ME algorithms with up to 53% of average coding time reduction whereas the coding efficiency can be maintained.Department of Electronic and Information Engineering2016-2017 > Academic research: refereed > Refereed conference paperbcw

Motion estimation in low-delay hierarchical p-frame coding using motion vector composition

Low-delay hierarchical prediction structure is currently adopted in various new video coding standards. The only hurdle of this structure is the need of motion estimation in distant reference frames. To maintain high coding efficiency, a large search range for motion estimation can improve the coding efficiency in distant reference pictures. Computational complexity will thus be increased dramatically. In this paper, a fast motion estimation scheme for a low-delay hierarchical P-frame structure is proposed. The proposed scheme adopts a motion vector composition strategy to expedite the motion estimation process for distant reference frames in the hierarchical P structure. In addition, a motion vector composition algorithm is tailor-made with the proposed hierarchical P coding scheme to further improve the coding efficiency. Simulation results show that the proposed scheme can deliver a remarkable complexity savings and coding efficiency improvement on coding a frame in low temporal layers of the hierarchical P structure.Department of Electronic and Information Engineerin

Adaptive search range for HEVC motion estimation based on depth information

High Efficient Video Coding (HEVC) achieves twofold coding efficiency improvement compared to its predecessor H.264/MPEG-4 AVC. However, it suffers from high computational complexity due to its quad-tree structure in motion estimation. This paper exposes the usage of depth maps in the multiview video plus depth format for relieving the computational burden. The depth map provides an intimation of the objects’ distance from the projected screen in a 3D scene, which is explored in adaptive search range determination in this paper. The proposed algorithm exploits the high temporal correlation between the depth map and the motion in texture. By utilizing this correlation, a depth/motion relationship map is built for a mapping process. For each block, this forms a tailor-made search range with a motion-aware asymmetric shape to skip unnecessary search points in motion estimation. The obtained search range can be further adjusted by taking the influence of 3D-to-2D projection into consideration. Simulation results reveal that, compared to the full search approach, the proposed algorithm can reduce the complexity by 93% on average whereas the coding efficiency can be maintained. Besides, the proposed search range determination can work well with other fast search motion estimation algorithms in the literature.Department of Electronic and Information Engineerin

Motion vector composition in low-delay hierarchical P-frame coding

2013 IEEE China Summit and International Conference on Signal and Information Processing, ChinaSIP 2013, Beijing, 6-10 July 2013Recent video coding standards such as high efficiency video coding (HEVC) and multi-view video coding (MVC) can obtain significant gain from hierarchical prediction structures. Hierarchical B structure utilizes future reference frames, which induces high encoding delay. Comparatively, hierarchical P structure brings low-delay coding in which no future references are involved. The only hurdle of the low-delay hierarchical P structure is the need of motion estimation in distant reference frames. To maintain a high coding efficiency, large search range for motion estimation was commonly adopted in distant reference pictures. Therefore, computational complexity will be increased dramatically. In this paper, motion vector composition is proposed in hierarchical P structure to shorten coding process. Simulation results reveal that the proposed scheme can achieve significant complexity savings.Department of Electronic and Information EngineeringRefereed conference pape