检索结果-南通市图书馆

A Survey of the Machine Learning Models for Forest Fire Prediction and Detection

在线全文

学校读者我要写书评

暂无评论

International Journal of Communications, Network and System Sciences 2023年第7期16卷 131-150页

作者： Prathibha Sobha shahram Latifi Department of Electrical and Computer Engineering University of Nevada Las Vegas Las Vegas USA

Forest fires are a significant threat to the environment, causing ecological damage, economic losses, and posing a threat to human life. Hence, timely detection and prevention of forest fires are critical to minimizing their impact. In this paper, we review the current state-of-the-art methods in forest fire detection and prevention using predictions based on weather conditions and predictions based on forest fire history. In particular, we discuss different Machine Learning (ML) models that have been used for forest fire detection. Further, we present the challenges faced when implementing the ML-based forest fire detection and prevention systems, such as data availability, model prediction errors and processing speed. Finally, we discuss how recent advances in Deep Learning (DL) can be utilized to improve the performance of current fire detection systems.

关键词： AI Computer Vision Deep Learning Forest Fires ML UAV

Hydrodynamical wind in magnetized accretion flows with convection

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2012年第12期12卷 1625-1636页

作者： shahram Abbassi Amin Mosallanezhad School of Physics Damghan UniversityP.O.Box 36715-364DamghanIran School of Astronomy Institute for Research in Fundamental SciencesP.O.Box 19395-5531 TehranIran Center for Excellence in Astronomy&Astrophysics(CEAA-RIAAM) P.O.Box 55134-441 MaraghaIran

The existence of outflow and magnetic fields in the inner region of hot accretion flows has been confirmed by observations and numerical magnetohydrodynamic（MHD）*** present self-similar solutions for radiatively inefficient accretion flows（RIAFs）around black holes in the presence of outflow and a global magnetic *** influence of outflow is taken into account by adopting a radius that depends on mass accretion rateM=M0 （r/r0）s with s〉0. We also consider convection through a mixing length formula to calculate convection parameterα*** we consider the additional magnetic field parameters βr,φ,z=c2 r,φ,z /（2c2 s ）,where c2 r,φ,z are the Alfvén sound speeds in three directions of cylindrical *** numerical results show that by increasing all components of the magnetic field,the surface density and rotational velocity increase,but the sound speed and radial infall velocity of the disk *** have also found that the existence of wind will lead to reduction of surface density as well as rotational ***,the radial velocity,sound speed,advection parameter and the vertical thickness of the disk will increase when outflow becomes important in the RIAF.

关键词： accretion:accretion flow-wind:outflow-convection:MHD

SOLUBLE POLYIMIDES FROM A SEMI-ALIPHATIC DIAMINE CONTAINING ESTER,AMIDE AND ETHER GROUPS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2011年第1期29卷 93-100页

作者： shahram Mehdipour-Ataei Leila Akbarian-Feizi Iran Polymer and Petrochemical Institute P.O.Box 14965/115TehranIran

A diamine was synthesized by two successive reactions. Nucleophilic reaction of 4-hydroxybenzoic acid with terephthaloyl chloride yielded terephthaloyl bis（4-oxybenzoic） acid. Then reaction of this compound with 1,8-diamino-3,6- dioxaoctane via Yamazaki method resulted in preparation of diamine named terephthalic acid bis（4-{2-[2-（2-amino ethoxy）ethoxy]ethyl carbamoyl}phenyl） ester. After fully characterization it was used to prepare new polyimides through polycondensation with different dianhydrides using trimethylchlorosilane. Characterization of polymers was achieved by common methods and their physical properties including inherent viscosity, thermal behavior, thermal stability, crystallinity and solubility were studied. Prepared polyimides showed improved solubility and good thermal stability.

关键词： Polyimide Polycondensation Synthesis Thermal properties

Effect of Bainite Morphology on Mechanical Properties of the Mixed Bainite-martensite Microstructure in D6AC Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2012年第4期28卷 336-342页

作者： Khodamorad Abbaszadeh Hassan Saghafian shahram Kheirandish School of Metallurgy and Materials Engineering Iran University of Science and Technology Tehran *** Iran

The effect of bainite morphology on mechanical properties of the mixed bainite-martensite microstructure in D6AC low alloy ultra-high strength steel has been studied in the present work. For this purpose, samples austenitized at 910℃ for 40 min were quenched in three different ways. Some of the samples were directly oil-quenched, some others were quenched in salt bath at 330 ℃ and the remaining samples were quenched in salt bath at 425 ℃ for various holding times. All samples were tempered at 200 ℃ for 2 h. Microstructures were examined by optical microscopy （OM） and scanning electron microscopy （SEM）. Fracture surfaces also were studied by SEM. Results showed that the mixed microstructure containing martensite and 28 vol.% of the lower bainite exhibited higher yield and tensile strengths than the fully martensitic microstructure. This could be mainly attributed to the partitioning of the prior austenite grains by the lower bainite and enhancing the strength of lower bainite in the mixed microstructure by plastic constraint. Charpy V-notch （CVN） impact energy and ductility were improved by increasing the volume fraction of the lower bainite. This is not the case about the mixed microstructure containing the upper bainite and martensite. As a result, the tensile and CVN impact properties of mixed upper bainite-martensite microstructure are lower than those of the fully martensitic microstructure. Finally, fractography studies showed cleavage fracture at the surface of CVN impact specimens with martensitic and upper bainitic microstructures confirming the tendency to brittle behavior.

关键词： Upper bainite Lower bainite Microstructure D6AC Mechanical properties

Effect of chemical activation process on adsorption of As(V) ion from aqueous solution by mechano-thermally synthesized zinc ferrite nanopowder

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2020年第4期27卷 526-537页

作者： Mohammad Sefidmooy Azar shahram Raygan Saeed Sheibani School of Metallurgy and Materials Engineering College of EngineeringUniversity of TehranTehranIran

Nanostructured ZnFe2O4 was synthesized by the heat treatment of a mechanically activated mixture of ZnO/α-Fe2O3.X-ray diffraction(XRD)and differential thermal analysis(DTA)results demonstrated that,after 5 h of the mechanical activation of the mixture,ZnFe2O4 was formed by heat treatment at 750°C for 2 *** improve the characteristics of ZnFe2O4 for adsorption applications,the chemical activation process was *** 2 h chemical activation with 1 mol·L?1 HNO3 and co-precipitation of 52%?57%dissolved ZnFe2O4 led to an increase in the saturated magnetization from 2.0 to 7.5 emu·g?1 and in the specific surface area from 5 to 198 m2·g?*** addition,the observed particle size reduction of chemically activated ZnFe2O4 in field emission scanning electron microscopy(FESEM)micrographs was in agreement with the specific surface area *** improvements in ZnFe2O4 characteristics considerably affected the adsorption performance of this *** results revealed that mechano-thermally synthesized ZnFe2O4 had the maximum arsenic adsorption of 38%with the adsorption capacity of 0.995 mg·g?1 in a 130 mg·L?1 solution of As(V)after 30 min of ***,chemically activated ZnFe2O4 showed the maximum arsenic adsorption of approximately 99%with the adsorption capacity of 21.460 mg·g?1 under the same *** results showed that the weak adsorption performance of mechano-thermally synthesized ZnFe2O4 was improved by the chemical activation process.

关键词： zinc ferrite mechano-thermal chemical activation adsorption arsenic(V)

Variational Calculation of Lattice SU(N) Gauge System

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1996年第5期13卷 337-339页

作者： ZHENG Xi-te shahram Alavian Department of Applied Physics Sichuan Union University(Chengdu University of Science and Technology)Chengdu 610065 Saskatchewan Accelerator Laboratory University of SaskatchewanSaskatoonSaskatchewanCanadaS7N5C6(present address)

A general method for an analytical calculation of SU(N)lattice gauge theories with finite N≥3 *** an example,the order parameter(E)of lattice SU(4)gauge systetn is *** result is in good agree^nent with Monte Carlo si... 详细信息

关键词： gauge lattice finite

Identification of lncRNAs associated with the progression of acute lymphoblastic leukemia using a competing endogenous RNAs network

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Oncology Research 2022年第6期30卷 259-268页

作者： shahram NEKOEIAN TAHEREH ROSTAMI AMIR NOROUZY SAFIN HUSSEIN GHOLAMREZA TAVOOSIDANA BAHRAM CHAHARDOULI SHAHRBANO ROSTAMI YAZDAN ASGARI ZAHRA AZIZI Department of Molecular Medicine School of Advanced Technologies in MedicineTehran University of Medical SciencesTehranIran Research Institute for Oncology Hematology and Cell TherapyShariati HospitalTehran University of Medical SciencesTehranIran Department of Energy&Environmental Biotechnology National Institute of Genetic Engineering and Biotechnology(NIGEB)TehranIran Department of Medical Laboratory Science University of RaparinRaniaKurdistan RegionIraq Department of Medical Biotechnology School of Advanced Technologies in MedicineTehran University of Medical SciencesTehranIran

Acute lymphoblastic leukemia(ALL)is a malignancy of bone marrow lymphoid *** effective treatments,the causes of its progression or recurrence are still *** prognostic biomarkers is needed for early diagnosis and more effective *** study was performed to identify long non-coding RNAs(lncRNAs)involved in ALL progression by constructing a competitive endogenous RNA(ceRNA)*** lncRNAs may serve as potential new biomarkers in the development of *** GSE67684 dataset identiﬁed changes in lncRNAs and mRNAs involved in ALL *** from this study were re-analyzed,and probes related to lncRNAs were ***,miRTarBase,and miRcode databases were used to identify microRNAs(miRNAs)related to the discovered genes and *** ceRNA network was constructed,and the candidate lncRNAs were ***,the results were validated with reverse transcription quantitative real-time PCR(RT-qPCR).The ceRNA network outcomes demonstrated that the top lncRNAs associated with altered mRNAs in ALL are IRF1-AS1,MCM3AP-AS1,TRAF3IP2-AS1,HOTAIRM1,CRNDE,and *** of the subnets linked to MCM3AP-AS1,TRAF3IP2-AS1,and IRF1-AS1 indicated that these lncRNAs were considerably related to pathways associated with inﬂammation,metastasis,and *** expression levels of IRF1-AS1,MCM3AP-AS1,TRAF3IP2-AS1,CRNDE,and TUG1 were found in ALL samples compared to *** expression of MCM3AP-AS1,TRAF3IP2-AS1,and IRF1-AS1 is signiﬁcantly elevated during the progression of ALL,playing an oncogenic *** to their role in the main cancer pathways,lncRNAs could be suitable therapeutic and diagnostic targets in ALL.

关键词： RT-qPCR ALL Non-coding RNAs microRNA Leukemia

An error-free protocol for quantum entanglement distribution in long-distance quantum communication

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2011年第7期56卷 618-625页

作者： SALEMIAN Shamsolah MOHAMMADNEJAD shahram Nanoptronics Research Center Department of Electronics and Electrical Engineering Iran University of Science and Technology

Quantum entanglement distribution is an essential part of quantum communication and computation protocols. Here, linear optic elements are employed for the distribution of quantum entanglement over a long distance. Polarization beam splitters and wave plates are used to realize an error-free protocol for broadcasting quantum entanglement in optical quantum communication. This protocol can determine the maximum distance of quantum communication without decoherence. Error detection and error correc-tion are performed in the proposed scheme. In other words, if there is a bit flip along the quantum channel, the end stations (Alice and Bob) can detect this state change and obtain the correct state (entangled photon) at another port. Existing general error detec-tion protocols are based on the quantum controlled-NOT (CNOT) or similar quantum logic operations, which are very difficult to implement experimentally. Here we present a feasible scheme for the implementation of entanglement distribution based on a linear optics element that does not need a quantum CNOT gate.

关键词：光量子通信量子纠缠协议长距离分发错误检测量子逻辑运算光学元件

Globally stable and high-performance Internet congestion control through a computational inspiration from nature

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2011年第6期54卷 1251-1263页

作者： AMALI shahram ANALOUI Morteza Computer Engineering Department University of Mohaghegh Ardabili Computer Engineering Department Iran University of Science and Technology

There are many reasons to worry that the current congestion control schemes in the Internet may be reaching its limits. Since the nature is a source of excellent solutions for complex problems, this work attempts to solve the congestion control problem, by adopting some biological principles and mechanisms. The current work proposes that the congestion problem in the Internet can be addressed through an inspiration from the population control tactics in nature. Toward this idea, each flow (W ) in the network is viewed as a species whose population size matches congestion window size of the flow. By this assumption, congestion control problem is redefined as population control of flow species. This paper defines a three-trophic food chain analogy in congestion control area, and gives a model to control population size of W species within this food chain. We call this model BICCTT and show mathematically, it is stable and efficient regardless of the link capacity, the round-trip delay, and number of flows. Extensive packet-level simulations in ns-2, show that BICCTT operates better than TCP/RED and XCP in both typical and high bandwidth-delay environments. BICCTT achieves fair bandwidth allocation, high utilization, small queue size, and near-zero packet drops. It does not maintain any per-flow state in routers and have low computational loads per packet, which makes it scalable.

关键词： nature-inspired algorithm congestion control TCP stability