As industrialization and informatization becomemore deeply intertwined,industrial control networks have entered an era of intelligence.The connection between industrial control networks and the external internet is be...As industrialization and informatization becomemore deeply intertwined,industrial control networks have entered an era of intelligence.The connection between industrial control networks and the external internet is becoming increasingly close,which leads to frequent security accidents.This paper proposes a model for the industrial control network.It includes a malware containment strategy that integrates intrusion detection,quarantine,and monitoring.Basedonthismodel,the role of keynodes in the spreadofmalware is studied,a comparisonexperiment is conducted to validate the impact of the containment strategy.In addition,the dynamic behavior of the model is analyzed,the basic reproduction number is computed,and the disease-free and endemic equilibrium of the model is also obtained by the basic reproduction number.Moreover,through simulation experiments,the effectiveness of the containment strategy is validated,the influence of the relevant parameters is analyzed,and the containment strategy is optimized.In otherwords,selective immunity to key nodes can effectively suppress the spread ofmalware andmaintain the stability of industrial control systems.The earlier the immunization of key nodes,the better.Once the time exceeds the threshold,immunizing key nodes is almost ineffective.The analysis provides a better way to contain the malware in the industrial control network.展开更多
[Objective] The study aimed at analyzing Genetic Differentiation of Cervinae. [Method] The complete mitochondrial DNA control region of five species of Cervinae was determined by direct DNA sequencing. Homologous sequ...[Objective] The study aimed at analyzing Genetic Differentiation of Cervinae. [Method] The complete mitochondrial DNA control region of five species of Cervinae was determined by direct DNA sequencing. Homologous sequences of others Cervinae were gained from GenBank, and then analyzed through biology software. [Result] The lengths of their control region were 921-1 072 bp, the nucleotide content of T, A, C, and G was 32.1%, 30.2%, 22.7% and 15.0% separately. Genetic distance of each species ranged from 0.062-0.106, which belonged to level of inter-genus. The molecular phylogenetic tree indicated that red deer, skia deer and White-lipped Deer had close relationship, and they constituted one branch with sambar deer. Eld's deer and elk deer constituted the second branch, and hog deer constituted the third branch alone. [Conclusion] Hog deer and fallow deer should be incorporated in Cervus, divergence time is about 1.55-2.60 million years among Cervinae in China.展开更多
In order to solve the problem of artificial generation and low efficiency of test sequences for zone controller (ZC), a model-based automatic generation method of test sequence is proposed. Firstly, the timed automata...In order to solve the problem of artificial generation and low efficiency of test sequences for zone controller (ZC), a model-based automatic generation method of test sequence is proposed. Firstly, the timed automata model is established based on function analysis of the zone controller, and the correctness of the model is verified by UPPAAL. Then by parsing the timed automata model files, state information and transition conditions can be extracted to generate test case sets. Finally, according to the serialization conditions of test cases, the test cases are serialized into test sequences by using the improved depth first search algorithm. A case, the ZC controls the train running within its jurisdiction, shows that the method is correct and can effectively improve the efficiency of test sequence generation.展开更多
To understand the evolution of the Miocene gravity flow deposits in the Lower Congo-Congo Fan Basin,this paper documents the Miocene sequence stratigraphic framework,the depositional characteristics and the controllin...To understand the evolution of the Miocene gravity flow deposits in the Lower Congo-Congo Fan Basin,this paper documents the Miocene sequence stratigraphic framework,the depositional characteristics and the controlling factors of the gravity flow system.Based on the establishment of high-resolution sequence stratigraphic framework,lithofacies characteristics and sedimentary units of the gravity flow deposits in the region are identified by using seismic,well logging and core data comprehensively,and the sedimentary evolution process is revealed and the controlling factors are discussed.The Miocene can be divided into four 3 rd-order sequences(SQ1-SQ4).The gravity flow deposits mainly include siliciclastic rock and pelite.The main sedimentary units include slumping deposits,mass transport deposits(MTD),channel fills,levee-overbank deposits,and frontal lobes.In the Early Miocene(SQ1),mainly gull-wing,weakly restricted to unrestricted depositional channel-overbank complexes and lobes were formed.In the early Middle Miocene(SQ2),W-shaped and weakly restricted erosional-depositional channels(multi-phase superposition)were subsequently developed.In the late Middle Miocene(SQ3),primarily U-shaped and restricted erosional channels were developed.In the Late Miocene(SQ4),largely V-shaped and deeply erosional isolated channels were formed in the study area.Climate cooling and continuous fall of the sea level made the study area change from toe of slope-submarine plain to lower continental slope,middle continental slope and finally to upper continental slope,which in turn affected the strength of the gravity flow.The three times of tectonic uplifting and climate cooling in the West African coast provided abundant sediment supply for the development of gravity flow deposits.Multistage activities of salt structures played important roles in redirecting,restricting,blocking and destroying the gravity flow deposits.Clarifying the characteristics,evolution and controlling factors of the Miocene gravity flow deposits in the Lower Congo-Congo Fan Basin can provide reference for deep-water petroleum exploration in this basin.展开更多
On the basis of the relationship between the Hamiltonian of spin 1/2 quantum system under control and the energy level structure and transitions, a radio frequency pulse sequence is designed using intuitive and half c...On the basis of the relationship between the Hamiltonian of spin 1/2 quantum system under control and the energy level structure and transitions, a radio frequency pulse sequence is designed using intuitive and half counter-intuitive sequences of pulse to transfer the population of the 3-qubit system coherently. The effectiveness of the designed control sequence is verified through the system simulation experiment of the evolution of state. In principle, the design method of the control pulse sequence proposed can be generalized to use in the quantum systems of higher dimension.展开更多
In this paper, the mutual information between clock-controlled input and output sequences is discussed. It is proved that the mutual information is a strictly monotone increasing function of the length of output seque...In this paper, the mutual information between clock-controlled input and output sequences is discussed. It is proved that the mutual information is a strictly monotone increasing function of the length of output sequence, and its divergent rate is gaven.展开更多
When D:ξ→η is a linear ordinary differential (OD) or partial differential (PD) operator, a “direct problem” is to find the generating compatibility conditions (CC) in the form of an operator D<sub>1:</su...When D:ξ→η is a linear ordinary differential (OD) or partial differential (PD) operator, a “direct problem” is to find the generating compatibility conditions (CC) in the form of an operator D<sub>1:</sub>η→ξ such that Dξ = η implies D<sub>1</sub>η = 0. When D is involutive, the procedure provides successive first-order involutive operators D<sub>1</sub>,...,D<sub>n </sub>when the ground manifold has dimension n. Conversely, when D<sub>1</sub> is given, a much more difficult “inverse problem” is to look for an operator D:ξ→η having the generating CC D<sub>1</sub>η = 0. If this is possible, that is when the differential module defined by D<sub>1</sub> is “torsion-free”, that is when there does not exist any observable quantity which is a sum of derivatives of η that could be a solution of an autonomous OD or PD equation for itself, one shall say that the operator D<sub>1</sub> is parametrized by D. The parametrization is said to be “minimum” if the differential module defined by D does not contain a free differential submodule. The systematic use of the adjoint of a differential operator provides a constructive test with five steps using double differential duality. We prove and illustrate through many explicit examples the fact that a control system is controllable if and only if it can be parametrized. Accordingly, the controllability of any OD or PD control system is a “built in” property not depending on the choice of the input and output variables among the system variables. In the OD case and when D<sub>1</sub> is formally surjective, controllability just amounts to the formal injectivity of ad(D<sub>1</sub>), even in the variable coefficients case, a result still not acknowledged by the control community. Among other applications, the parametrization of the Cauchy stress operator in arbitrary dimension n has attracted many famous scientists (G. B. Airy in 1863 for n = 2, J. C. Maxwell in 1870, E. Beltrami in 1892 for n = 3, and A. Einstein in 1915 for n = 4). We prove that all these works are already explicitly using the self-adjoint Einstein operator, which cannot be parametrized and the comparison needs no comment. As a byproduct, they are all based on a confusion between the so-called div operator D<sub>2</sub> induced from the Bianchi operator and the Cauchy operator, adjoint of the Killing operator D which is parametrizing the Riemann operator D<sub>1</sub> for an arbitrary n. This purely mathematical result deeply questions the origin and existence of gravitational waves, both with the mathematical foundations of general relativity. As a matter of fact, this new framework provides a totally open domain of applications for computer algebra as the quoted test can be studied by means of Pommaret bases and related recent packages.展开更多
By using m-sequence over the finite field GF(2m) of degree L to control m-sequence over GF(2m) of degree L, a class of periodic sequences with large linear complexity is constructed. The lower bounds of the linear com...By using m-sequence over the finite field GF(2m) of degree L to control m-sequence over GF(2m) of degree L, a class of periodic sequences with large linear complexity is constructed. The lower bounds of the linear complexity of these sequences are L((L +1)m-Lm).展开更多
Power control is an important issue in mobile communication systems and has been studied extensively in the literature. This paper has taken on a new perspective and modeled the problem as a state estimation problem w...Power control is an important issue in mobile communication systems and has been studied extensively in the literature. This paper has taken on a new perspective and modeled the problem as a state estimation problem with finite communication constraints. The problem is solved by using the 1-bit mean coder-estimator sequence. The performance of the coder-estimator sequence is compared with that of the simple feedback power control technique by evaluating their respective fade margins as in commonly done in radio system engineering.展开更多
The 5’-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids spe...The 5’-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids species retrieved from GenBank. A phylogenetic tree was constructed based on the partial control region sequences. The results of phyloge- netic analysis are consistent with those of conventional systematics. Compared to previous studies, the structure of the 5’-end of mitochondrial control region was analyzed. The terminal associated sequence motif and its complementary motif were i- dentified at the 5’-end of the sequences. A conserved sequence block, named as CM5’d, was identified in the 5’-end of con- trol region sequences in all Pleuronectids. Another central conserved sequence block, named as CSB-F, was detected in the central conserved blocks.展开更多
The configuration an electric vehicle's electrical system and its control sequence design scheme was discussed. Vehicle management unit (VMU), power management unit (PMU) and battery management unit (BMU) were use...The configuration an electric vehicle's electrical system and its control sequence design scheme was discussed. Vehicle management unit (VMU), power management unit (PMU) and battery management unit (BMU) were used as the control units in the vehicle. VMU was used as master control unit, PMU was used as the traction control unit and BMU was used as battery management unit. The concentrated single module control was found to be on one of its configurations.展开更多
The poly(vinylpyridine)(PVP) based(co)polymers are of particular interest in materials science, due to their multifunctionality and diverse applications. So far, there is no report on the sequence-regulated copolymeri...The poly(vinylpyridine)(PVP) based(co)polymers are of particular interest in materials science, due to their multifunctionality and diverse applications. So far, there is no report on the sequence-regulated copolymerization of vinylpyridines(VPs) and methacrylate monomer in one-step manner yet. Here we designed and synthesized a series of guanidine phosphines as Lewis base(LB), which is combined with bulky organoaluminium to construct Lewis pairs(LPs) for polymerization of VPs. The living/controlled polymerization of 4-vinylpyridine(4-VP) or 2-vinylpyridine(2-VP) can be accomplished with remarkable efficiency by such Lewis pair polymerization(LPP), furnishing polymers with high molecular weight(up to 288 kg/mol) and narrow molecular weight distribution(as low as 1.17). Mechanistic studies reveal the interaction of LPs and formation of zwitterionic intermediates, providing solid evidences to support the proposed polymerization mechanism. More importantly, by simply adjusting the LA dosage, this LPP strategy realizes the unprecedented control over the sequence regulation of 2-VP-based copolymers from gradient to block in one-step manner, regardless of the monomer ratio, which greatly expands the versatility of the LPP.展开更多
The modular multilevel matrix converter(M3C)is a potential frequency converter for low-frequency AC transmission.However,capacitor voltage control of high-voltage and largecapacity M3C is more difficult,especially for...The modular multilevel matrix converter(M3C)is a potential frequency converter for low-frequency AC transmission.However,capacitor voltage control of high-voltage and largecapacity M3C is more difficult,especially for voltage balancing between branches.To solve this problem,this paper defines sequence circulating components and theoretically analyzes the influence mechanism of different sequence circulating components on branch capacitor voltage.A fully decoupled branch energy balancing control method based on four groups of sequence circulating components is proposed.This method can control capacitor voltages of nine branches in horizontal,vertical and diagonal directions.Considering influences of both circulating current and voltage,a cross decoupled control is designed to improve control precision.Simulation results are taken from a low-frequency transmission system based on PSCAD/EMTDC,and effectiveness and precision of the proposed branch energy balancing control method are verified in the case of nonuniform parameters and an unbalanced power system.展开更多
In this study,four sequencing batch reactors(SBR),with the sludge retention time(SRT)of 5,10,20 and 40 d,were used to treat domestic wastewater,and the effect of SRT on nitrite accumulation in the biological nitrogen ...In this study,four sequencing batch reactors(SBR),with the sludge retention time(SRT)of 5,10,20 and 40 d,were used to treat domestic wastewater,and the effect of SRT on nitrite accumulation in the biological nitrogen removal SBR was investigated.The real-time control strategy based on online parameters,such as pH,dissolved oxygen(DO)and oxidation reduction potential(ORP),was used to regulate the nitrite accumulation in SBR. The model-based simulation and experimental results showed that with the increase of SRT,longer time was needed to achieve high level of nitritation.In addition,the nitrite accumulation rate(NAR)was higher when the SRT was relatively shorter during a 112-day operation.When the SRT was 5 d,the system was unstable with the mixed liquor suspended solids(MLSS)decreased day after day.When the SRT was 40 d,the nitrification process was significantly inhibited.SRT of 10 to 20 d was more suitable in this study.The real-time control strategy combined with SRT control in SBR is an effective method for biological nitrogen removal via nitrite from wastewater.展开更多
The study and comparison of sequences of characters from a finite alphabet is relevant to various areas of science, notably molecular biology. The measurement of sequence similarity involves the consideration of the p...The study and comparison of sequences of characters from a finite alphabet is relevant to various areas of science, notably molecular biology. The measurement of sequence similarity involves the consideration of the possible sequence alignments in order to find an optimal one for which the “distance” between sequences is minimum. In biology informatics area, it is a more important and difficult problem due to the long length (100 at least) of sequence, this cause the compute complexity and large memory require. By associating a path in a lattice to each alignment, a geometric insight can be brought into the problem of finding an optimal alignment, this give an obvious encoding of each path. This problem can be solved by applying genetic algorithm, which is more efficient than dynamic programming and hidden Markov model using commomly now.展开更多
In developing distributed systems, conformance testing is required to determine whether an implementation under test (IUT) conforms to its specification. With distributed test architectures involving multiple remote...In developing distributed systems, conformance testing is required to determine whether an implementation under test (IUT) conforms to its specification. With distributed test architectures involving multiple remote testers, testing approaches may become more complicated because of issues known as controllability and observability problems. Based on a finite state machine (FSM) representation of the system's specification, this paper proposes a new method to generate a test sequence utilizing multiple UIO sequences. The method is essentially guided by the way of minimizing the use of external coordination messages and input/output operations. Experiments are given to evaluate the proposed method.展开更多
Weedy rice exerts a severe impact on rice production by competing for sunlight, water and nutrients. This study assayed the population structure, genetic diversity and origin of Northeast Asia weedy rice by using 48 s...Weedy rice exerts a severe impact on rice production by competing for sunlight, water and nutrients. This study assayed the population structure, genetic diversity and origin of Northeast Asia weedy rice by using 48 simple sequence repeat markers. The results showed that weedy rice in Northeast Asia had a high genetic diversity, with Shannon's diversity index (I) of 0.748 and the heterozygosity (He) of 0.434. In each regional population, I value varied widely. The widest range of I (0.228-0.489) was observed in the weedy rice of Eastern China, which was larger than that of Northeast China and Korea (0.168-0.270). The F-statistics of regional populations (Fis, Fit and Fst) also showed higher values in the weedy rice of Eastern China than those of Northeast China and Korea All weedy rice accessions were grouped into two clusters in the unweighted pair group method with arithmetic mean cluster analysis dendrogram, namely Eastern China branch and Northeastern China plus Korea branch. There was significant differentiation in genetic characteristics in weedy rice of northeastern and eastern Asia, especially in Eastern China.展开更多
In a quantum key distribution system, it is crucial to keep the extinction ratio of the coherent pulses stable. This means that the direct current bias point of the electro-optic modulator (EOM) used for generating ...In a quantum key distribution system, it is crucial to keep the extinction ratio of the coherent pulses stable. This means that the direct current bias point of the electro-optic modulator (EOM) used for generating coherent pulses must be locked. In this paper, an autobias control system based on a lock-in-amplifier for the EOM is introduced. Its drift information extracting theory and control method are analyzed comprehensively. The long term drift of the extinction ratio of the coherent pulses is measured by a single photon detector, which indicates that the autobias control system is effective for stabilizing the bias point of the EOM.展开更多
The genomic sequence of the attenuated hog cholera virus Lapinized Chinese strain (HCLV) was determined from overlapping cDNA clones. The viral RNA of HCLV stain comprised 12 310 nucleotide (nt) including 374 nt and 2...The genomic sequence of the attenuated hog cholera virus Lapinized Chinese strain (HCLV) was determined from overlapping cDNA clones. The viral RNA of HCLV stain comprised 12 310 nucleotide (nt) including 374 nt and 239 nt at the 5′ and 3′-noncoding region, respectively. The complete genome sequence contained one large open reading frame which encoded an amino acid sequence of 3 898 residues with a calculated molecular weight of 437×103. Although there were mostly only small differences between the sequence of the HCLV strain and the published sequences of strains ALD, GPE?, Alfort and Brescia, there was one notable insertion of 12 nucleotides, TTTTCTTTTTTC in the 3′ non-coding region of HCLV strain.展开更多
According to the previously published CSFV sequences, 18 paris of partially overlapping primers which span the entire genome of CSFV strain Shimen were designed and synthesized. Each cDNA fragment of strain Shimen was...According to the previously published CSFV sequences, 18 paris of partially overlapping primers which span the entire genome of CSFV strain Shimen were designed and synthesized. Each cDNA fragment of strain Shimen was amplified by RT-PCR method from the anticoagulant blood of strain Shimen infected pig. The PCR fragments were cloned into pGEM-T vector respectively and sequenced. The results show that we have obtained the nucleotide sequence of strain Shimen. The viral RNA consists of 12 297 nucleotides including noncoding regions of 373 and 227 bases at the 5′ and 3′ end, respectively, and a single large open reading frame spanning 11 697 nucleotides in the middle, which encodes an amino acid sequence of 3 989 residues with a calculated molecular weight of 437.6×103. The precisely sequencing of 5′ and 3′ termini is undertaking.展开更多
基金Scientific Research Project of Liaoning Province Education Department,Code:LJKQZ20222457&LJKMZ20220781Liaoning Province Nature Fund Project,Code:No.2022-MS-291.
文摘As industrialization and informatization becomemore deeply intertwined,industrial control networks have entered an era of intelligence.The connection between industrial control networks and the external internet is becoming increasingly close,which leads to frequent security accidents.This paper proposes a model for the industrial control network.It includes a malware containment strategy that integrates intrusion detection,quarantine,and monitoring.Basedonthismodel,the role of keynodes in the spreadofmalware is studied,a comparisonexperiment is conducted to validate the impact of the containment strategy.In addition,the dynamic behavior of the model is analyzed,the basic reproduction number is computed,and the disease-free and endemic equilibrium of the model is also obtained by the basic reproduction number.Moreover,through simulation experiments,the effectiveness of the containment strategy is validated,the influence of the relevant parameters is analyzed,and the containment strategy is optimized.In otherwords,selective immunity to key nodes can effectively suppress the spread ofmalware andmaintain the stability of industrial control systems.The earlier the immunization of key nodes,the better.Once the time exceeds the threshold,immunizing key nodes is almost ineffective.The analysis provides a better way to contain the malware in the industrial control network.
基金Supported by National Science and Technology Support Program(2007BAI38B03)National Platform Project for Natural Science and Technology Rescources(No.2004DKA30460)~~
文摘[Objective] The study aimed at analyzing Genetic Differentiation of Cervinae. [Method] The complete mitochondrial DNA control region of five species of Cervinae was determined by direct DNA sequencing. Homologous sequences of others Cervinae were gained from GenBank, and then analyzed through biology software. [Result] The lengths of their control region were 921-1 072 bp, the nucleotide content of T, A, C, and G was 32.1%, 30.2%, 22.7% and 15.0% separately. Genetic distance of each species ranged from 0.062-0.106, which belonged to level of inter-genus. The molecular phylogenetic tree indicated that red deer, skia deer and White-lipped Deer had close relationship, and they constituted one branch with sambar deer. Eld's deer and elk deer constituted the second branch, and hog deer constituted the third branch alone. [Conclusion] Hog deer and fallow deer should be incorporated in Cervus, divergence time is about 1.55-2.60 million years among Cervinae in China.
文摘In order to solve the problem of artificial generation and low efficiency of test sequences for zone controller (ZC), a model-based automatic generation method of test sequence is proposed. Firstly, the timed automata model is established based on function analysis of the zone controller, and the correctness of the model is verified by UPPAAL. Then by parsing the timed automata model files, state information and transition conditions can be extracted to generate test case sets. Finally, according to the serialization conditions of test cases, the test cases are serialized into test sequences by using the improved depth first search algorithm. A case, the ZC controls the train running within its jurisdiction, shows that the method is correct and can effectively improve the efficiency of test sequence generation.
基金Supported by the China National Science and Technology Major Project(2016ZX05004-002)National Natural Science Foundation of China(91328201)。
文摘To understand the evolution of the Miocene gravity flow deposits in the Lower Congo-Congo Fan Basin,this paper documents the Miocene sequence stratigraphic framework,the depositional characteristics and the controlling factors of the gravity flow system.Based on the establishment of high-resolution sequence stratigraphic framework,lithofacies characteristics and sedimentary units of the gravity flow deposits in the region are identified by using seismic,well logging and core data comprehensively,and the sedimentary evolution process is revealed and the controlling factors are discussed.The Miocene can be divided into four 3 rd-order sequences(SQ1-SQ4).The gravity flow deposits mainly include siliciclastic rock and pelite.The main sedimentary units include slumping deposits,mass transport deposits(MTD),channel fills,levee-overbank deposits,and frontal lobes.In the Early Miocene(SQ1),mainly gull-wing,weakly restricted to unrestricted depositional channel-overbank complexes and lobes were formed.In the early Middle Miocene(SQ2),W-shaped and weakly restricted erosional-depositional channels(multi-phase superposition)were subsequently developed.In the late Middle Miocene(SQ3),primarily U-shaped and restricted erosional channels were developed.In the Late Miocene(SQ4),largely V-shaped and deeply erosional isolated channels were formed in the study area.Climate cooling and continuous fall of the sea level made the study area change from toe of slope-submarine plain to lower continental slope,middle continental slope and finally to upper continental slope,which in turn affected the strength of the gravity flow.The three times of tectonic uplifting and climate cooling in the West African coast provided abundant sediment supply for the development of gravity flow deposits.Multistage activities of salt structures played important roles in redirecting,restricting,blocking and destroying the gravity flow deposits.Clarifying the characteristics,evolution and controlling factors of the Miocene gravity flow deposits in the Lower Congo-Congo Fan Basin can provide reference for deep-water petroleum exploration in this basin.
基金supported by the National Natural Science Foundation of China (60774098)the National Key Basic Research Program (2006922004)
文摘On the basis of the relationship between the Hamiltonian of spin 1/2 quantum system under control and the energy level structure and transitions, a radio frequency pulse sequence is designed using intuitive and half counter-intuitive sequences of pulse to transfer the population of the 3-qubit system coherently. The effectiveness of the designed control sequence is verified through the system simulation experiment of the evolution of state. In principle, the design method of the control pulse sequence proposed can be generalized to use in the quantum systems of higher dimension.
文摘In this paper, the mutual information between clock-controlled input and output sequences is discussed. It is proved that the mutual information is a strictly monotone increasing function of the length of output sequence, and its divergent rate is gaven.
文摘When D:ξ→η is a linear ordinary differential (OD) or partial differential (PD) operator, a “direct problem” is to find the generating compatibility conditions (CC) in the form of an operator D<sub>1:</sub>η→ξ such that Dξ = η implies D<sub>1</sub>η = 0. When D is involutive, the procedure provides successive first-order involutive operators D<sub>1</sub>,...,D<sub>n </sub>when the ground manifold has dimension n. Conversely, when D<sub>1</sub> is given, a much more difficult “inverse problem” is to look for an operator D:ξ→η having the generating CC D<sub>1</sub>η = 0. If this is possible, that is when the differential module defined by D<sub>1</sub> is “torsion-free”, that is when there does not exist any observable quantity which is a sum of derivatives of η that could be a solution of an autonomous OD or PD equation for itself, one shall say that the operator D<sub>1</sub> is parametrized by D. The parametrization is said to be “minimum” if the differential module defined by D does not contain a free differential submodule. The systematic use of the adjoint of a differential operator provides a constructive test with five steps using double differential duality. We prove and illustrate through many explicit examples the fact that a control system is controllable if and only if it can be parametrized. Accordingly, the controllability of any OD or PD control system is a “built in” property not depending on the choice of the input and output variables among the system variables. In the OD case and when D<sub>1</sub> is formally surjective, controllability just amounts to the formal injectivity of ad(D<sub>1</sub>), even in the variable coefficients case, a result still not acknowledged by the control community. Among other applications, the parametrization of the Cauchy stress operator in arbitrary dimension n has attracted many famous scientists (G. B. Airy in 1863 for n = 2, J. C. Maxwell in 1870, E. Beltrami in 1892 for n = 3, and A. Einstein in 1915 for n = 4). We prove that all these works are already explicitly using the self-adjoint Einstein operator, which cannot be parametrized and the comparison needs no comment. As a byproduct, they are all based on a confusion between the so-called div operator D<sub>2</sub> induced from the Bianchi operator and the Cauchy operator, adjoint of the Killing operator D which is parametrizing the Riemann operator D<sub>1</sub> for an arbitrary n. This purely mathematical result deeply questions the origin and existence of gravitational waves, both with the mathematical foundations of general relativity. As a matter of fact, this new framework provides a totally open domain of applications for computer algebra as the quoted test can be studied by means of Pommaret bases and related recent packages.
文摘By using m-sequence over the finite field GF(2m) of degree L to control m-sequence over GF(2m) of degree L, a class of periodic sequences with large linear complexity is constructed. The lower bounds of the linear complexity of these sequences are L((L +1)m-Lm).
基金Supported by a grant from the Hong Kong Research Grants Councilpartially supported by Shenzhen University
文摘Power control is an important issue in mobile communication systems and has been studied extensively in the literature. This paper has taken on a new perspective and modeled the problem as a state estimation problem with finite communication constraints. The problem is solved by using the 1-bit mean coder-estimator sequence. The performance of the coder-estimator sequence is compared with that of the simple feedback power control technique by evaluating their respective fade margins as in commonly done in radio system engineering.
基金the Shandong Foundation of Sciences(No.Y2000D04) the National Key Basic Research Program from the Ministry of Science and Technology of China(No.G19990437).
文摘The 5’-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids species retrieved from GenBank. A phylogenetic tree was constructed based on the partial control region sequences. The results of phyloge- netic analysis are consistent with those of conventional systematics. Compared to previous studies, the structure of the 5’-end of mitochondrial control region was analyzed. The terminal associated sequence motif and its complementary motif were i- dentified at the 5’-end of the sequences. A conserved sequence block, named as CM5’d, was identified in the 5’-end of con- trol region sequences in all Pleuronectids. Another central conserved sequence block, named as CSB-F, was detected in the central conserved blocks.
文摘The configuration an electric vehicle's electrical system and its control sequence design scheme was discussed. Vehicle management unit (VMU), power management unit (PMU) and battery management unit (BMU) were used as the control units in the vehicle. VMU was used as master control unit, PMU was used as the traction control unit and BMU was used as battery management unit. The concentrated single module control was found to be on one of its configurations.
基金supported by the National Natural Science Foundation of China (22225104, 92356302 and 22071077)China Postdoctoral Science Foundation (2022TQ0115 and 2022M711297)。
文摘The poly(vinylpyridine)(PVP) based(co)polymers are of particular interest in materials science, due to their multifunctionality and diverse applications. So far, there is no report on the sequence-regulated copolymerization of vinylpyridines(VPs) and methacrylate monomer in one-step manner yet. Here we designed and synthesized a series of guanidine phosphines as Lewis base(LB), which is combined with bulky organoaluminium to construct Lewis pairs(LPs) for polymerization of VPs. The living/controlled polymerization of 4-vinylpyridine(4-VP) or 2-vinylpyridine(2-VP) can be accomplished with remarkable efficiency by such Lewis pair polymerization(LPP), furnishing polymers with high molecular weight(up to 288 kg/mol) and narrow molecular weight distribution(as low as 1.17). Mechanistic studies reveal the interaction of LPs and formation of zwitterionic intermediates, providing solid evidences to support the proposed polymerization mechanism. More importantly, by simply adjusting the LA dosage, this LPP strategy realizes the unprecedented control over the sequence regulation of 2-VP-based copolymers from gradient to block in one-step manner, regardless of the monomer ratio, which greatly expands the versatility of the LPP.
基金supported by National Key R&D Program of China(No.2021YFB2401100).
文摘The modular multilevel matrix converter(M3C)is a potential frequency converter for low-frequency AC transmission.However,capacitor voltage control of high-voltage and largecapacity M3C is more difficult,especially for voltage balancing between branches.To solve this problem,this paper defines sequence circulating components and theoretically analyzes the influence mechanism of different sequence circulating components on branch capacitor voltage.A fully decoupled branch energy balancing control method based on four groups of sequence circulating components is proposed.This method can control capacitor voltages of nine branches in horizontal,vertical and diagonal directions.Considering influences of both circulating current and voltage,a cross decoupled control is designed to improve control precision.Simulation results are taken from a low-frequency transmission system based on PSCAD/EMTDC,and effectiveness and precision of the proposed branch energy balancing control method are verified in the case of nonuniform parameters and an unbalanced power system.
基金Supported by the National Key Technologies Research and Development Program of China during the Eleventh Five-year Plan Period(2006BAC19B03)the Project of Scientific Research Base and Scientific Innovation Platform of Beijing Municipal Education Commission(PXM2008_014204_050843the State Key Laboratory of Urban Water Resource and Environment(HIT)(QAK201006)
文摘In this study,four sequencing batch reactors(SBR),with the sludge retention time(SRT)of 5,10,20 and 40 d,were used to treat domestic wastewater,and the effect of SRT on nitrite accumulation in the biological nitrogen removal SBR was investigated.The real-time control strategy based on online parameters,such as pH,dissolved oxygen(DO)and oxidation reduction potential(ORP),was used to regulate the nitrite accumulation in SBR. The model-based simulation and experimental results showed that with the increase of SRT,longer time was needed to achieve high level of nitritation.In addition,the nitrite accumulation rate(NAR)was higher when the SRT was relatively shorter during a 112-day operation.When the SRT was 5 d,the system was unstable with the mixed liquor suspended solids(MLSS)decreased day after day.When the SRT was 40 d,the nitrification process was significantly inhibited.SRT of 10 to 20 d was more suitable in this study.The real-time control strategy combined with SRT control in SBR is an effective method for biological nitrogen removal via nitrite from wastewater.
文摘The study and comparison of sequences of characters from a finite alphabet is relevant to various areas of science, notably molecular biology. The measurement of sequence similarity involves the consideration of the possible sequence alignments in order to find an optimal one for which the “distance” between sequences is minimum. In biology informatics area, it is a more important and difficult problem due to the long length (100 at least) of sequence, this cause the compute complexity and large memory require. By associating a path in a lattice to each alignment, a geometric insight can be brought into the problem of finding an optimal alignment, this give an obvious encoding of each path. This problem can be solved by applying genetic algorithm, which is more efficient than dynamic programming and hidden Markov model using commomly now.
基金Project supported by the National Natural Science Foundation of China (Grant No.60673115), and the Open Foundation of State Key Laboratory of Software Engineering (Grant No.SKLSE05-13)
文摘In developing distributed systems, conformance testing is required to determine whether an implementation under test (IUT) conforms to its specification. With distributed test architectures involving multiple remote testers, testing approaches may become more complicated because of issues known as controllability and observability problems. Based on a finite state machine (FSM) representation of the system's specification, this paper proposes a new method to generate a test sequence utilizing multiple UIO sequences. The method is essentially guided by the way of minimizing the use of external coordination messages and input/output operations. Experiments are given to evaluate the proposed method.
基金funded by Shanghai Municipal Key Task Projects of Prospering Agriculture by Science and Technology Plan in China (Grant No. Hu Nong Ke Gong Zi 2008: 2-1)
文摘Weedy rice exerts a severe impact on rice production by competing for sunlight, water and nutrients. This study assayed the population structure, genetic diversity and origin of Northeast Asia weedy rice by using 48 simple sequence repeat markers. The results showed that weedy rice in Northeast Asia had a high genetic diversity, with Shannon's diversity index (I) of 0.748 and the heterozygosity (He) of 0.434. In each regional population, I value varied widely. The widest range of I (0.228-0.489) was observed in the weedy rice of Eastern China, which was larger than that of Northeast China and Korea (0.168-0.270). The F-statistics of regional populations (Fis, Fit and Fst) also showed higher values in the weedy rice of Eastern China than those of Northeast China and Korea All weedy rice accessions were grouped into two clusters in the unweighted pair group method with arithmetic mean cluster analysis dendrogram, namely Eastern China branch and Northeastern China plus Korea branch. There was significant differentiation in genetic characteristics in weedy rice of northeastern and eastern Asia, especially in Eastern China.
基金Project supported by the National Natural Science Foundation of China(Grant No.61108039)the Major Research Plan of the National Natural Science Foundation of China(Grant No.91121023)the Scientific Research Foundation of Graduate School of South China Normal University(Grant No.2012kyjj224)
文摘In a quantum key distribution system, it is crucial to keep the extinction ratio of the coherent pulses stable. This means that the direct current bias point of the electro-optic modulator (EOM) used for generating coherent pulses must be locked. In this paper, an autobias control system based on a lock-in-amplifier for the EOM is introduced. Its drift information extracting theory and control method are analyzed comprehensively. The long term drift of the extinction ratio of the coherent pulses is measured by a single photon detector, which indicates that the autobias control system is effective for stabilizing the bias point of the EOM.
文摘The genomic sequence of the attenuated hog cholera virus Lapinized Chinese strain (HCLV) was determined from overlapping cDNA clones. The viral RNA of HCLV stain comprised 12 310 nucleotide (nt) including 374 nt and 239 nt at the 5′ and 3′-noncoding region, respectively. The complete genome sequence contained one large open reading frame which encoded an amino acid sequence of 3 898 residues with a calculated molecular weight of 437×103. Although there were mostly only small differences between the sequence of the HCLV strain and the published sequences of strains ALD, GPE?, Alfort and Brescia, there was one notable insertion of 12 nucleotides, TTTTCTTTTTTC in the 3′ non-coding region of HCLV strain.
文摘According to the previously published CSFV sequences, 18 paris of partially overlapping primers which span the entire genome of CSFV strain Shimen were designed and synthesized. Each cDNA fragment of strain Shimen was amplified by RT-PCR method from the anticoagulant blood of strain Shimen infected pig. The PCR fragments were cloned into pGEM-T vector respectively and sequenced. The results show that we have obtained the nucleotide sequence of strain Shimen. The viral RNA consists of 12 297 nucleotides including noncoding regions of 373 and 227 bases at the 5′ and 3′ end, respectively, and a single large open reading frame spanning 11 697 nucleotides in the middle, which encodes an amino acid sequence of 3 989 residues with a calculated molecular weight of 437.6×103. The precisely sequencing of 5′ and 3′ termini is undertaking.