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Peter Liu,Albert Y. Chen,Yin-Nan Huang,Jen-Yu Han,Jihn-Sung Lai,Tzong-Hann Wu,Ming-Chang Wen,Meng-Han Tsai,Shih-Chung Kang 국제구조공학회 2014 Smart Structures and Systems, An International Jou Vol.13 No.6
Civil engineers always face the challenge of uncertainty in planning, building, and maintaininginfrastructure. These works rely heavily on a variety of surveying and monitoring techniques. Unmannedaerial vehicles (UAVs) are an effective approach to obtain information from an additional view, andpotentially bring significant benefits to civil engineering. This paper gives an overview of the state of UAVdevelopments and their possible applications in civil engineering. The paper begins with an introduction toUAV hardware, software, and control methodologies. It also reviews the latest developments in technologiesrelated to UAVs, such as control theories, navigation methods, and image processing. Finally, the paperconcludes with a summary of the potential applications of UAV to seismic risk assessment, transportation,disaster response, construction management, surveying and mapping, and flood monitoring and assessment.
Internet Roundtrip Delay Prediction Using the Maximum Entropy Principle
Liu, Peter Xiaoping,Meng, Max Q-H,Gu, Jason The Korea Institute of Information and Commucation 2003 Journal of communications and networks Vol.5 No.1
Internet roundtrip delay/time (RTT) prediction plays an important role in detecting packet losses in reliable transport protocols for traditional web applications and determining proper transmission rates in many rate-based TCP-friendly protocols for Internet-based real-time applications. The widely adopted autoregressive and moving average (ARMA) model with fixed-parameters is shown to be insufficient for all scenarios due to its intrinsic limitation that it filters out all high-frequency components of RTT dynamics. In this paper, we introduce a novel parameter-varying RTT model for Internet roundtrip time prediction based on the information theory and the maximum entropy principle (MEP). Since the coefficients of the proposed RTT model are updated dynamically, the model is adaptive and it tracks RTT dynamics rapidly. The results of our experiments show that the MEP algorithm works better than the ARMA method in both RTT prediction and RTO estimation.
Liu, Peter,Chen, Albert Y.,Huang, Yin-Nan,Han, Jen-Yu,Lai, Jihn-Sung,Kang, Shih-Chung,Wu, Tzong-Hann,Wen, Ming-Chang,Tsai, Meng-Han Techno-Press 2014 Smart Structures and Systems, An International Jou Vol.13 No.6
Civil engineers always face the challenge of uncertainty in planning, building, and maintaining infrastructure. These works rely heavily on a variety of surveying and monitoring techniques. Unmanned aerial vehicles (UAVs) are an effective approach to obtain information from an additional view, and potentially bring significant benefits to civil engineering. This paper gives an overview of the state of UAV developments and their possible applications in civil engineering. The paper begins with an introduction to UAV hardware, software, and control methodologies. It also reviews the latest developments in technologies related to UAVs, such as control theories, navigation methods, and image processing. Finally, the paper concludes with a summary of the potential applications of UAV to seismic risk assessment, transportation, disaster response, construction management, surveying and mapping, and flood monitoring and assessment.
Liu, Xiuyun,Donnelly, Joseph,Czosnyka, Marek,Aries, Marcel J. H.,Brady, Ken,Cardim, Danilo,Robba, Chiara,Cabeleira, Manuel,Kim, Dong-Joo,Haubrich, Christina,Hutchinson, Peter J.,Smielewski, Peter Public Library of Science 2017 PLoS medicine Vol.14 No.7
<▼1><P><B>Background</B></P><P>After traumatic brain injury (TBI), the ability of cerebral vessels to appropriately react to changes in arterial blood pressure (pressure reactivity) is impaired, leaving patients vulnerable to cerebral hypo- or hyperperfusion. Although, the traditional pressure reactivity index (PRx) has demonstrated that impaired pressure reactivity is associated with poor patient outcome, PRx is sometimes erratic and may not be reliable in various clinical circumstances. Here, we introduce a more robust transform-based wavelet pressure reactivity index (wPRx) and compare its performance with the widely used traditional PRx across 3 areas: its stability and reliability in time, its ability to give an optimal cerebral perfusion pressure (CPPopt) recommendation, and its relationship with patient outcome.</P><P><B>Methods and findings</B></P><P>Five hundred and fifteen patients with TBI admitted in Addenbrooke’s Hospital, United Kingdom (March 23rd, 2003 through December 9th, 2014), with continuous monitoring of arterial blood pressure (ABP) and intracranial pressure (ICP), were retrospectively analyzed to calculate the traditional PRx and a novel wavelet transform-based wPRx. wPRx was calculated by taking the cosine of the wavelet transform phase-shift between ABP and ICP. A time trend of CPPopt was calculated using an automated curve-fitting method that determined the cerebral perfusion pressure (CPP) at which the pressure reactivity (PRx or wPRx) was most efficient (CPPopt_PRx and CPPopt_wPRx, respectively).</P><P>There was a significantly positive relationship between PRx and wPRx (r = 0.73), and wavelet wPRx was more reliable in time (ratio of between-hour variance to total variance, wPRx 0.957 ± 0.0032 versus PRx and 0.949 ± 0.047 for PRx, <I>p</I> = 0.002). The 2-hour interval standard deviation of wPRx (0.19 ± 0.07) was smaller than that of PRx (0.30 ± 0.13, <I>p</I> < 0.001). wPRx performed better in distinguishing between mortality and survival (the area under the receiver operating characteristic [ROC] curve [AUROC] for wPRx was 0.73 versus 0.66 for PRx, <I>p</I> = 0.003). The mean difference between the patients’ CPP and their CPPopt was related to outcome for both calculation methods. There was a good relationship between the 2 CPPopts (r = 0.814, <I>p</I> < 0.001). CPPopt_wPRx was more stable than CPPopt_PRx (within patient standard deviation 7.05 ± 3.78 versus 8.45 ± 2.90; <I>p</I> < 0.001).</P><P>Key limitations include that this study is a retrospective analysis and only compared wPRx with PRx in the cohort of patients with TBI. Prior prospective validation is required to better assess clinical utility of this approach.</P><P><B>Conclusions</B></P><P>wPRx offers several advantages to the traditional PRx: it is more stable in time, it yields a more consistent CPPopt recommendation, and, importantly, it has a stronger relationship with patient outcome. The clinical utility of wPRx should be explored in prospective studies of critically injured neurological patients.</P></▼1><▼2><P>Using continuous monitoring data in traumatic brain inury patients, Xiuyun Liu and colleagues compare the performance of cerebrovascular pressure reactivity monitoring using wavelet analysis to the pressure reactivity index.</P></▼2><▼3><P><B>Author summary</B></P><P><B>Why was this study done?</B></P><P>The brain is vulnerable to damage from too little (ischemia) or too much (hyperemia) blood flow following traumatic brain injury (TBI).</P><P>A physiological mechanism called cerebral autoregulation (CA) exists to maintain stable blood flow even if cerebral perfusion pressure (CPP) is changing, and an assessment of CA as part of bedside neuro-monitoring of patients with TBI could facilitate individualized treatment.</P><P>A robust method for assessing CA in TBI is not yet available. The traditional measure used, the pressure reactivity index (PRx), provides inherently noisy estimates and
Liu, Jianming,Wang, Zhihao,Kandasamy, Vijayalakshmi,Lee, Sang Yup,Solem, Christian,Jensen, Peter Ruhdal Elsevier 2017 Metabolic engineering Vol.44 No.-
<P><B>Abstract</B></P> <P>When modifying the metabolism of living organisms with the aim of achieving biosynthesis of useful compounds, it is essential to ensure that it is possible to achieve overall redox balance. We propose a generalized strategy for this, based on fine-tuning of respiration. The strategy was applied on metabolically engineered <I>Lactococcus lactis</I> strains to optimize the production of acetoin and (<I>R</I>,<I>R</I>)-2,3-butanediol (R-BDO). In the absence of an external electron acceptor, a surplus of two NADH per acetoin molecule is produced. We found that a fully activated respiration was able to efficiently regenerate NAD<SUP>+</SUP>, and a high titer of 371mM (32g/L) of acetoin was obtained with a yield of 82% of the theoretical maximum. Subsequently, we extended the metabolic pathway from acetoin to R-BDO by introducing the butanediol dehydrogenase gene from <I>Bacillus subtilis</I>. Since one mole of NADH is consumed when acetoin is converted into R-BDO per mole, only the excess of NADH needs to be oxidized via respiration. Either by fine-tuning the respiration capacity or by using a dual-phase fermentation approach involving a switch from fully respiratory to non-respiratory conditions, we obtained 361mM (32g/L) R-BDO with a yield of 81% or 365mM (33g/L) with a yield of 82%, respectively. These results demonstrate the great potential in using finely-tuned respiration machineries for bio-production.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fine-tuning of the reducing power availability via respiration. </LI> <LI> Respiration capacity modulated through hemin concentration. </LI> <LI> High titer and yield production of acetoin by harnessing respiration. </LI> <LI> Production of (R,R)-2,3-butanediol by using a fine-tuned respiration. </LI> <LI> A dual phase fermentation approach developed for (R,R) 2,3-butanediol biosynthesis. </LI> </UL> </P>
Hairui Liu,Wei Wang,Yaohui He,Peter Hastie 대한운동학회 2020 아시아 운동학 학술지 Vol.22 No.3
[OBJECTIVES] This study examined the development of Chinese pre-service physical education teachers’ technical skill, tactical understanding, game performance (common content knowledge - CCK), and specialized content knowledge (SCK) during a badminton course incorporating Play Practice instruction. [METHODS] Participants were 36 pre-service teachers (31 males, 5 females: age 21 ± 1.0) majoring in physical education at a university in central China. The students completed a 24 lesson course after a 16 weeks semester. A typical lesson (90 minutes) included a 10-minute warm-up, followed by instruction in two or three technical skills or tactics for 50-55 minutes. The final 25-minutes included the Play Practice aspect of the lesson - a specific game-based challenge to reinforce a technical or tactical aspect of badminton play. The challenge included the three typical pedagogies of Play Practice: focusing, shaping, and enhancing. The French clear test, tactical understanding in badminton, Game Performance Assessment Instrument (GPAI), and student-generated content maps were used to respectively monitor changes in technical skills, tactical understanding, game performance, and specialized content knowledge before and after the course. Parametric statistics were used to compare student outcomes. [RESULTS] Statistically significant differences were found on all measures from pre- to post-test, with all showing large effect sizes. In particular, over 75% of students achieved the benchmark depth of SCK following the course. [CONCLUSIONS] The inclusion of Play Practice within a sport instruction course can contribute to various elements that are needed to promote the CCK and SCK of pre-service physical education students.