Cost-minimizing preemptive scheduling of mapreduce workloads on hybrid clouds

MapReduce has become the dominant programming model for processing massive amounts of data on cloud platforms. More and more enterprises are now utilizing hybrid clouds, consisting of private infrastructure owned by themselves and public clouds such as Amazon EC2, to process their spiky MapReduce workloads, which fully utilize their own on-premise resources while outsourcing the tasks only when needed. With disparate workloads of different MapReduce tasks, an efficient scheduling mechanism is in need to enable efficient utilization of the on-premise resources and to minimize the task outsourcing cost, while meeting the task completion time requirements as well. In this paper, a fine-grained model is described to characterize the scheduling of heterogeneous MapReduce workloads, and an online algorithm is proposed for joint task admission control into the private cloud, task outsourcing to the public cloud, and VM allocation to execute the admitted tasks on the private cloud, such that the time-averaged task outsourcing cost is minimized over the long run. The online algorithm features preemptive scheduling of the tasks, where a task executed partially on the on-premise infrastructure can be paused and scheduled to run later. It also achieves desirable properties such as meeting a pre-set task admission ratio and bounding the worst-case task completion time, as proven by our rigorous theoretical analysis. © 2013 IEEE.published_or_final_versio

Cantonese Prosody: Sentence-final Particles and Prosodic Focus

Fundamental frequency (F0) is the most important feature among the components of prosody in a language, tone and intonation languages alike. In a tone language, how lexical tone and sentence intonation can both use F0 as their main acoustic cues has long been an intriguing question. Will the lexical tones be so resistant to modification that no elaborate intonation is possible in the language? How much of the surface sentential F0 is attributable to lexical tones and intonation? If F0 modification is kept minimal, how will prosodic focus be realized? And will the lack of focus-related F0 change be a disadvantage in terms of focus perception? In this dissertation, experimental studies have been made on Cantonese in some less well-understood aspects of its prosody. Firstly, the tonal characteristics of sentence-final particles (SFPs) in Cantonese as a special case of the interaction between tone and intonation are examined. Secondly, the acoustic correlates of prosodic focus in Cantonese are explored. SFPs are a class of words known to have functions similar to intonation. It is not yet clear, however, whether the F0 contours of SFPs are derived purely from lexical tones, purely intonational, or a combination of tone and intonation. As an attempt to offer a solution, a production experiment was designed in which sentences in Hong Kong Cantonese with ten different SFPs were recorded and detailed analyses of their F0 contours, final F0, final F0 velocity and duration were performed. The results show that most of these SFPs are very similar to the lexical tones in terms of F0 contours, but there are significant differences in durations in more than half the cases. In addition, the occurrence of an SFP does not give rise to differences in F0 and duration in the syllables preceding the SFP in most cases. But differences can be seen in sentences with question SFPs, which indicates that the prosody of the SFPs may be partly due to intonational meanings. One of the SFPs, however, exhibits a component F0 contour that seems to be sequentially attached to the end of the lexical tonal component. These findings suggest that Cantonese SFPs have underlying tonal targets just like those of lexical tones, but they also carry intonational meanings by modifying the lexical tonal contours. Previous research has shown that Beijing Mandarin, a tone language, marks focus not only by on-focus prosodic expansion like many other languages, but also by post-focus compression of pitch range and intensity (PFC). However, recently it is found that PFC is absent in Taiwanese and Taiwan Mandarin, two languages closely related to Beijing Mandarin. This finding both highlights the non-universality of PFC and raises questions about its origin. The present study explores these issues by investigating focus production in Cantonese by native Cantonese speakers born and raised in Hong Kong, and in English and Cantonese by bilingual speakers who were born and raised in Southern England. Results from the Hong Kong speakers show that, just as in Taiwanese and Taiwan Mandarin, PFC is absent in Cantonese, and mean F0, duration, intensity and excursion size were found to be higher in on-focus words. Results from the bilingual speakers show that their Cantonese also lacks PFC. More remarkably, out of the fifteen bilinguals tested, only one-third show PFC in all their English test sentences. These findings suggest that PFC is hard to transmit across languages through bilingualism. Moreover, the differential prosodic patterns among the bilingual speakers suggest that in the bilingual community, PFC may be subject to gradual loss. Although tone-intonation relationship in SFPs and the acoustic correlates have previously been studied, most of the discussion lacked supporting evidence from phonetic experiments. The present study is distinguished in its systematic experimental design and detailed acoustic analyses, and it is hoped that the results will lay the foundations for future investigations into Cantonese phonetics

Persistence of hepatic hepatitis B virus after serological clearance of HBsAG with autologous peripheral stem cell transplantation

Delayed clearance of hepatitis B surface antigen was previously reported in a 38 year old woman after high dose chemotherapy with autologous peripheral blood stem cell rescue. Sixteen months later, this patient remained hepatitis B surface antigen negative, hepatitis B surface anti-body positive, and serum hepatitis B DNA negative by polymerase chain reaction. Serial liver biopsies (one at hepatitis B e antigen positive stage, one at hepatitis B e antibody positive stage, and one at hepatitis B surface antigen negative and hepatitis B surface antibody positive stage) showed a gradual resolution of the inflammatory activity with loss of hepatitis B e antigen and then hepatitis B surface antigen in the serum. However, the degree of fibrosis, though mild, remained the same. With the serological clearance of hepatitis B surface antigen, a small amount of hepatitis B virus DNA was still detectable in the nuclei of liver cells.published_or_final_versio

Molecular Identification of Spirometra erinaceieuropaei Tapeworm in Cases of Human Sparganosis, Hong Kong

Human sparganosis is a foodborne zoonosis endemic in Asia. We report a series of 9 histologically confirmed human sparganosis cases in Hong Kong, China. All parasites were retrospectively identified as Spirometra erinaceieuropaei. Skin and soft tissue swelling was the most common symptom, followed by central nervous system lesions.published_or_final_versio

Microstructures and resistivity of cuprate/manganite bilayer deposited on SrTiO3 substrate

Thin Yba[SUB2]Cu[SUB3]O[SUB7-δ/La[SUB0.67]Ca[SUB0.33]MnO[SUB3] (YBCO/LCMO) films were grown on SrTiO[SUB3](STO)substrates by magnetron sputtering technique. The microstructures of the bilayers were characterized and a standard four-probe technique was applied to measure the resistivity of the samples. The interdiffusions at the YBCO/LCMO and LCMO/STO interfaces formed two transient layers with the thickness of about 3 and 2 nm, respectively. All the bilayers were well textured along the c axis. At low temperature, the superconductivity can only be observed when the thickness of YBCO is more than 25 nm. When the thickness of YBCO is less than 8 nm, the bilayers show only ferromagnetism. The superconductivity and ferromagnetism perhaps coexist in the bilayer with the YBCO thickness of 12.5 nm. These interesting properties are related to the interaction between spin polarized electrons in the manganites and the cooper pairs in the cuprates. © 2003 American Institute of Physics.published_or_final_versio

Long-Term Visual Object Tracking Benchmark

We propose a new long video dataset (called Track Long and Prosper - TLP) and benchmark for single object tracking. The dataset consists of 50 HD videos from real world scenarios, encompassing a duration of over 400 minutes (676K frames), making it more than 20 folds larger in average duration per sequence and more than 8 folds larger in terms of total covered duration, as compared to existing generic datasets for visual tracking. The proposed dataset paves a way to suitably assess long term tracking performance and train better deep learning architectures (avoiding/reducing augmentation, which may not reflect real world behaviour). We benchmark the dataset on 17 state of the art trackers and rank them according to tracking accuracy and run time speeds. We further present thorough qualitative and quantitative evaluation highlighting the importance of long term aspect of tracking. Our most interesting observations are (a) existing short sequence benchmarks fail to bring out the inherent differences in tracking algorithms which widen up while tracking on long sequences and (b) the accuracy of trackers abruptly drops on challenging long sequences, suggesting the potential need of research efforts in the direction of long-term tracking.Comment: ACCV 2018 (Oral

Superconductivity at 43 K in Samarium-arsenide Oxides SmFeAsO1−xFxSmFeAsO_{1-x}F_x

Since the discovery of high-transition temperature ($T_c$) superconductivity in layered copper oxides, extensive efforts have been devoted to explore the higher $T_c$ superconductivity. However, the $T_c$ higher than 40 K can be obtained only in the copper oxide superconductors so far. The highest reported value of $T_c$ for non-copper-oxide bulk superconductivity is 39 K in $MgB_2$.\cite{jun} The $T_c$ of about 40 K is close to or above the theoretical value predicted from BCS theory.\cite{mcmillan} Therefore, it is very significant to search for non-copper oxide superconductor with the transition temperature higher than 40 K to understand the mechanism of high-$T_c$ superconductivity. Here we report the discovery of bulk superconductivity in samarium-arsenide oxides $SmFeAsO_{1-x}F_x$ with ZrCuAiAs type structure. Resistivity and magnetization measurements show strong evidences for transition temperature as high as 43 K. $SmFeAsO_{1-x}F_x$ is the first non-copper oxide superconductor with $T_c$ higher than 40 K. The $T_c$ higher than 40 K may be a strong argument to consider $SmFeAsO_{1-x}F_x$ as an unconventional superconductor.Comment: 8 pages, 4 figure

Studying learning performance using a M-Learning Approach

Author name used in this manuscript: G. T. S. HoRefereed conference paper2013-2014 > Academic research: refereed > Refereed conference paperOther Versio

Vectorial Control of Magnetization by Light

Coherent light-matter interactions have recently extended their applications to the ultrafast control of magnetization in solids. An important but unrealized technique is the manipulation of magnetization vector motion to make it follow an arbitrarily designed multi-dimensional trajectory. Furthermore, for its realization, the phase and amplitude of degenerate modes need to be steered independently. A promising method is to employ Raman-type nonlinear optical processes induced by femtosecond laser pulses, where magnetic oscillations are induced impulsively with a controlled initial phase and an azimuthal angle that follows well defined selection rules determined by the materials' symmetries. Here, we emphasize the fact that temporal variation of the polarization angle of the laser pulses enables us to distinguish between the two degenerate modes. A full manipulation of two-dimensional magnetic oscillations is demonstrated in antiferromagnetic NiO by employing a pair of polarization-twisted optical pulses. These results have lead to a new concept of vectorial control of magnetization by light

The K526R substitution in viral protein ​PB2 enhances the effects of E627K on influenza virus replication

Host-adaptive strategies, such as the E627K substitution in the ​PB2 protein, are critical for replication of avian influenza A viruses in mammalian hosts. Here we show that mutation ​PB2-K526R is present in some human H7N9 influenza isolates, in nearly 80% of H5N1 human isolates from Indonesia and, in conjunction with E627K, in almost all seasonal H3N2 viruses since 1970. Polymerase complexes containing ​PB2-526R derived from H7N9, H5N1 or H3N2 viruses exhibit increased polymerase activity. ​PB2-526R also enhances viral transcription and replication in cells. In comparison with viruses carrying 627K, H7N9 viruses carrying both 526R and 627K replicate more efficiently in mammalian (but not avian) cells and in mouse lung tissues, and cause greater body weight loss and mortality in infected mice. ​PB2-K526R interacts with nuclear export protein and our results suggest that it contributes to enhance replication for certain influenza virus subtypes, particularly in combination with 627K.published_or_final_versio