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A Learning Automata-based Algorithm for Area Coverage Problem in Directional Sensor Networks
( Zhimin Liu ),( Zhangdong Ouyang ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.10
Coverage problem is a research hot spot in directional sensor networks (DSNs). However, the major problem affecting the performance of the current coverage-enhancing strategies is that they just optimize the coverage of networks, but ignore the maximum number of sleep sensors to save more energy. Aiming to find an approximate optimal method that can cover maximum area with minimum number of active sensors, in this paper, a new scheduling algorithm based on learning automata is proposed to enhance area coverage, and shut off redundant sensors as many as possible. To evaluate the performance of the proposed algorithm, several experiments are conducted. Simulation results indicate that the proposed algorithm have effective performance in terms of coverage enhancement and sleeping sensors compared to the existing algorithms.
On a perturbed Sparre Andersen risk model with dividend barrier and dependence
Zhimin Zhang,Xiu Wu,Hu Yang 한국통계학회 2014 Journal of the Korean Statistical Society Vol.43 No.4
In this paper, we consider a Sparre Andersen risk model perturbed by a Brownian motion,where the inter-claim time and individual claim size follow some bivariate distribution. Assume that a barrier dividend strategy is applied to the surplus process, so that dividendsare paid out whenever the surplus level attains a barrier b. Integral equations and integrodifferentialequations satisfied by the Gerber–Shiu discounted penalty functions and theexpected discounted dividend payments are derived, and solutions are also given for somespecial cases.
Nonparametric estimation for derivatives of compound distribution
Zhimin Zhang,Chaolin Liu 한국통계학회 2015 Journal of the Korean Statistical Society Vol.44 No.3
The compound random variableNj =1 Xj and its distribution have many applications in actuarial science. In this paper, we consider estimation of the derivative functionals of the compound distribution when the underlying density f of Xj is unknown. The estimator is constructed by Fourier inversion and kernel method. An order bound for the bias and asymptotic expression for the variance are given, and the asymptotic normality and uniform consistency are also discussed. Some simulation studies are presented to illustrate the performance of the estimator under finite sample setting.
Characterization of a strong green tissue-specific motif in rice photosystem I gene promoter Ppsak
Zhimin Lin,Jingwan Yan,Huanxin Yan,Feng Wang 한국식물생명공학회 2017 Plant biotechnology reports Vol.11 No.2
Characterization of green tissue-specific promoters helps facilitate genetic improvement in crops. Here, we isolated a novel green tissue-specific expression gene Psak encoding photosystem I protein in rice through RTPCR analysis. The 5′ flanking region from −635 to +60 (transcription start site of Psak as +1) covering parts of Psak gene and its promoter Ppsak was identified as be critical for green tissue-specific expression (including leaves and stems) in rice. Further promoter deletion analyses demonstrated that the promoter region from −559 to −232 was necessary and sufficient for green tissue-specific expression of Psak gene. Histochemical assays showed that the GUS expression of this 267-bp region was highly presented in leaves and stems, but reduced or absent in other tissues examined. The GUS expression level of this core promoter region could be 14.6- to 21.6-fold higher than that of the full-length region of Ppsak promoter in leaves and stems. These results combined with cis-acting elements prediction in Ppsak promoter suggested that the TCT motif located in this promoter played a key role in strong green tissue-specific expression.
( Zhimin Ou ),( Jiahui Xu ),( Lihua Du ),( Lan Tang ),( Yangping Niu ),( Jian Cui ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.4
In this study, interface-assembled carbonyl reductase (IACR) was prepared and used in the synthesis of S-licarbazepine in a toluene/Tris-HCl biphasic system. The carbonyl reductase (CR) was conjugated with polystyrene to form a surfactant-like structure at the interface of the toluene/Tris-HCl biphasic system. The interface-assembled efficiency of IACR reached 83% when the CR (180 U/mg) and polystyrene concentration were 8 × 10<sup>2</sup> g/ml and 3.75 × 10<sup>3</sup> g/ml, respectively. The conversion reached 95.6% and the enantiometric excess of S-licarbazepine was 98.6% when 3.97 × 10<sup>6</sup> nmol/l oxcarbazepine was converted by IACR using 6% ethanol as a co-substrate in toluene/Tris-HCl (12.5:10) at 30°C and 43 ×g for 6 h. IACR could be reused efficiently five times.
Zhimin Yu,Mou-Ming Zhao,Huiping Li,Hai-Feng Zhao,Qingli Zhang,Chunyan Wan,Huipin Li 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.4
High gravity (HG) or very high gravity (VHG)brewing has become popular in modern breweries due to its economic and product quality advantages. However,there are the negative impacts such as the fermentation performance of brewer’s yeast in HG or VHG wort, which are closely related to changes in cell physiological activity. In the present study, 3 kinds of worts, with different gravities, were used to examine the systematic effects on fermentation performance and physiological activity of lager yeast FBY009505 (Saccharomyces pastorianus) and ale yeast FBY0099 (Saccharomyces cerevisiae), as well as the resulting beer flavor. Results showed that the responses of FBY009505 and FBY0099 to the HG or VHG worts were similar. The specific fermentation rate and viability of cropped yeast of FBY009505 and FBY0099 were decreased with increasing wort gravity. The increased wort gravity resulted in the increase of energy charge and the decrease of α-glucosides transport rate and glycolytic enzyme activities. Moreover, the environmental stresses in the HG or VHG wort showed a higher inhibitory activity against α-glucoside transport than glycolytic enzymes. The content of intracellular trehalose and glycerol of FBY009505 and FBY0099 increased with the increase in wort gravity. The results from this study provided a potential means to systematically understand the physiology of brewer’s yeast under HG or VHG conditions. High gravity (HG) or very high gravity (VHG)brewing has become popular in modern breweries due to its economic and product quality advantages. However,there are the negative impacts such as the fermentation performance of brewer’s yeast in HG or VHG wort, which are closely related to changes in cell physiological activity. In the present study, 3 kinds of worts, with different gravities, were used to examine the systematic effects on fermentation performance and physiological activity of lager yeast FBY009505 (Saccharomyces pastorianus) and ale yeast FBY0099 (Saccharomyces cerevisiae), as well as the resulting beer flavor. Results showed that the responses of FBY009505 and FBY0099 to the HG or VHG worts were similar. The specific fermentation rate and viability of cropped yeast of FBY009505 and FBY0099 were decreased with increasing wort gravity. The increased wort gravity resulted in the increase of energy charge and the decrease of α-glucosides transport rate and glycolytic enzyme activities. Moreover, the environmental stresses in the HG or VHG wort showed a higher inhibitory activity against α-glucoside transport than glycolytic enzymes. The content of intracellular trehalose and glycerol of FBY009505 and FBY0099 increased with the increase in wort gravity. The results from this study provided a potential means to systematically understand the physiology of brewer’s yeast under HG or VHG conditions.
Sensor Density for Full-View Problem in Heterogeneous Deployed Camera Sensor Networks
( Zhimin Liu ),( Guiyan Jiang ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.12
In camera sensor networks (CSNs), in order to better identify the point, full-view problem requires capture any facing direction of target (point or intruder), and its coverage prediction and sensor density issues are more complicated. At present, a lot of research supposes that a large number of homogeneous camera sensors are randomly distributed in a bounded square monitoring region to obtain full-view rate which is close to 1. In this paper, we deduce the sensor density prediction model in heterogeneous deployed CSNs with arbitrary full-view rate. Aiming to reduce the influence of boundary effect, we introduce the concepts of expanded monitoring region and maximum detection area. Besides, in order to verify the performance of the proposed sensor density model, we carried out different scenarios in simulation experiments to verify the theoretical results. The simulation results indicate that the proposed model can effectively predict the sensor density with arbitrary full-view rate.