1,682 research outputs found
Rapid recovery of tigers <i>Panthera tigris</i> in Parsa Wildlife Reserve, Nepal
No full textAbstractInformation on density and abundance of globally threatened species such as tigers Panthera tigris is essential for effective conservation as well as to evaluate the success of conservation programmes. We monitored tigers in Parsa Widlife Reserve, Nepal, using camera traps, in 2013, 2014 and 2016. Once believed to be a sink for tigers from adjacent Chitwan National Park, Parsa now provides a new hope for tigers. Spatially explicit capture–recapture analysis over 3 survey years revealed an increase in tiger density from 0.78 to 1.38 individuals per 100 km2 from 2013 to 2016. The tiger abundance was estimated to be seven (6–13), 11 (10–16) and 17 (17–20) in 2013, 2014 and 2016, respectively. Resettlement of communities from the core area, reduced anthropogenic pressure, and improved security have made Parsa Wildlife Reserve a suitable habitat for tigers. Tiger abundance increased considerably within a 5 km radius of the evacuated village sites, from two in 2013 to eight in 2014 and 10 in 2016. Population turnover has remained moderate (< 30% per year), with persistence of individuals in multiple years. Dispersing tigers from Chitwan's source population accounted for a large portion (c. 40%) of the tigers detected in Parsa. Conservation efforts along with annual monitoring should be continued in Parsa to sustain the increase and monitor the persistence of tigers. The Chitwan–Parsa complex should be managed as a single ecological unit for conserving the Endangered tiger and other wide-ranging species.</jats:p
A comprehensive assessment of power system resilience to a hurricane using a two-stage analytical approach incorporating risk-based index
No full textSustainability of power systems is a vital need for modern societies. The occurrence of extreme weather events, such as hurricanes, may lead to blackouts. Hence, power systems resilience is a critical issue for experts. The main focus of this paper is on how to assess power system resilience comprehensively. In this regard, a two-stage framework is proposed. In the first stage, an approach is presented to evaluate power system resilience against a single intensity of a hurricane, which is called snapshot resilience assessment. The Cost of Energy Not Supplied (CENS) is regarded as a primary criterion. A risk measure called Conditional Value at Risk (CVaR) is incorporated into this approach to manage the risk of experiencing unfavorable failure scenarios. Accordingly, CVaR of CENS is proposed as an index in this stage. In the second stage, an approach for comprehensive resilience assessment is proposed, which is based on the trend of changing the values of snapshot resilience indices over a range of intensities of the event. The applicability of the proposed framework is tested in the IEEE 24-bus system. Finally, to examine the accuracy of the framework, the resilience of the test system is re-evaluated after applying a resilience improvement method
Data for publication: "Dynamic behavior of shear-thickening tluids under harmonic excitation: an experimental investigation"
No full textThe dataset accompanying the publication "Dynamic Behavior of Shear-Thickening Fluids under Harmonic Excitation: An Experimental Investigation" is now provided exclusively as a single archive:STF Dynamic Behavior Analysis: MATLAB CodeThis repository contains the MATLAB code and all accompanying files inside Suplimentary material.zip and the separate ZIP file “Experimental Paper_Mechanical Systems and Signal Processing_Elsevier.zip,” associated with the paper:"Dynamic Behavior of Shear-Thickening Fluids under Harmonic Excitation: An Experimental Investigation"OverviewThese scripts process experimental data, perform parameter identification for the oscillator system, and generate figures demonstrating the dynamic behavior of shear-thickening fluids (STFs) under harmonic excitation.PrerequisitesMATLAB (R2019b or newer recommended)Inside Supplementary_material.zip, you will find:All .txt experimental data files:RecordedExperimentalDataWithoutSTFOmega0.txtRecordedExperimentalDataWithoutSTFOmegaIncreasingRate0_047.txtRecordedExperimentalDataWithSTFOmegaIncreasingRate0_0333.txtRecordedExperimentalDataWithSTFOmegaConstant8_2.txtRecordedExperimentalDataWithSTFOmegaConstant11_3.txtThe main MATLAB scripts and auxiliary functions for data processing, parameter identification, and figure generation.Any related documentation (including the paper PDF, if applicable).Execution StepsFollow these steps to process the data and generate all figures:1. Data FiltrationRun prepare_mat_data.mProcesses raw experimental data exported from LabVIEW.Applies polynomial fitting to compute rotation speed, velocity, and acceleration.Generates .mat files containing the filtered data for further analysis.2. Free Vibration Parameter IdentificationRun identOscDyn_freeMotion.mUses Nelder-Mead optimization to determine stiffness (k), damping (c), and friction (T) parameters.Minimizes the objective function (Eq. 14) to match simulation with experimental data.Generates Figure 3 comparing simulation vs. experiment.Saves identified parameters in par0.3. Forced Vibration Parameter Identification and Figure GenerationRun identOscDyn_forcedMotion.mBuilds on free-vibration parameters for forced vibration.Generates Figures 4–8, showing:Excitation frequency vs. time (Fig. 4)Resistance force vs. velocity (Fig. 5)Displacement comparison (Fig. 6)Velocity comparison (Fig. 7)Frequency response (Fig. 8)Saves refined parameters to par1.4. Additional FiguresAutomatic generation of:Figure 13: STF force relationships in the resonance region (Section 6.1.2).Figure 15: Time histories in the post-resonance region (Section 6.1.3).Figure 16: STF force relationships in the post-resonance region (Section 6.1.3).Figure 17: STF behavior at constant excitation frequency (Section 6.1.3).Figure 18: Frequency response comparison with and without STF (Section 6.2).TroubleshootingPath Issues: Keep all files in the same directory or update path references in the scripts.Optimization Variability: Multiple runs may be needed due to the stochastic nature of Nelder-Mead.Memory Constraints: For large datasets, reduce data size or increase MATLAB’s allocated memory.Additional InformationFor questions or issues regarding the code, please contact the corresponding author as indicated in the paper.© 2025 | All rights reserved by the authors of"Dynamic Behavior of Shear-Thickening Fluids under Harmonic Excitation: An Experimental Investigation."Additional Note: Paper Source FilesAlso included in this repository is a second ZIP file, “Experimental Paper_Mechanical Systems and Signal Processing_Elsevier.zip,” containing:elsarticle-template folderElsevier’s LaTeX class/template files (e.g., elsarticle.cls and elsarticle-template.tex).Figure 1.jpg through Figure 18.jpgHigh-resolution figures referenced in the manuscript (see image in the screenshot: 18 total JPG files).mybibfile.bibA BibTeX reference database, ensuring proper citation management.These items allow you to compile the full manuscript (in LaTeX) for submission to Mechanical Systems and Signal Processing (Elsevier), with all figures and references properly linked.</p
Detection of algorithmically-generated domains: An adversarial machine learning approach
No full textDomain name detection techniques are widely used to detect Algorithmically Generated Domain names (AGD) applied by Botnets. A major difficulty with these algorithms is to detect those generated names which are meaningful. In this way, Command and Control (C2) servers are detected. Machine learning techniques have been of great use to generalize the attributes of the meaningful names, generated algorithmically. To resist such techniques, the distribution of characters is used as a basis to generate meaningful domain names. Such techniques are called adversarial attacks attempting to fool machine learning methods. However, our experiments with more than 252757 samples show that in addition to character distribution of domain names, randomness property and pronounceability attributes are of great use to detect such meaningful names. Using these additional attributes, we have been able to identify malicious domain names with an accuracy of 98.19%
A Multilabel Fuzzy Relevance Clustering System for Malware Attack Attribution in the Edge Layer of Cyber-Physical Networks
No full textThe rapid increase in the number of malicious programs has made malware forensics a daunting task and caused users' systems to become in danger. Timely identification of malware characteristics including its origin and the malware sample family would significantly limit the potential damage of malware. This is a more profound risk in Cyber-Physical Systems (CPSs), where a malware attack may cause significant physical damage to the infrastructure. Due to limited on-device available memory and processing power in CPS devices, most of the efforts for protecting CPS networks are focused on the edge layer, where the majority of security mechanisms are deployed. Since the majority of advanced and sophisticated malware programs are combining features from different families, these malicious programs are not similar enough to any existing malware family and easily evade binary classifier detection. Therefore, in this article, we propose a novel multilabel fuzzy clustering system for malware attack attribution. Our system is deployed on the edge layer to provide insight into applicable malware threats to the CPS network. We leverage static analysis by utilizing Opcode frequencies as the feature space to classify malware families. We observed that a multilabel classifier does not classify a part of samples. We named this problem the instance coverage problem. To overcome this problem, we developed an ensemble-based multilabel fuzzy classification method to suggest the relevance of a malware instance to the stricken families. This classifier identified samples of VirusShare, RansomwareTracker, and BIG2015 with an accuracy of 94.66%, 94.26%, and 97.56%, respectively
Inferring species absence from zero-sighting records using analytical Bayesian models with population growth
No full textCode and data for: B. Barnes, F. Giannini, M. Parsa and D. Ramsey"Inferring species absence from zero-sighting records using analytical Bayesian models with population growth" (under review
Targeting in International Law : Counterinsurgency and the Legal Materiality of the Principle of Distinction
No full textThis book is about how distinctions are drawn between civilians and combatants in modern warfare and how the legal principle of distinction depends on the technical means through which combatants make themselves visibly distinguishable from civilians. The author demonstrates that technologies of visualisation have always been part of the operation of the principle of distinction, arguing that the military uniform sustained the legal categories of civilian and combatant and actively set the boundaries of permissible and prohibited targeting, and so legal and illegal killing. Drawing upon insights from the theory of legal materiality, visual studies, critical fashion studies, and a dozen of military manuals he shows that far from being passive objects of regulation, these technologies help to draw the boundaries of the legitimate target. With its attention to the co-productive relationship between law, technologies of visualisation and legitimation of violence, this book will be relevant to a large community of researchers in international law, international relations, critical military studies, contemporary counterinsurgency operations and the sociology of law. © 2024 Amin Parsa
Meso-scale soğutma cihazlar deneysel ve sayısal sıcaklık transfer analiz sayısal
No full textVarious thermal management strategies and related technologies are recently developed based on the specific needs, which they are designed to fulfill. Some of these technologies are muffin fans, synthetic jets, and piezoelectric fans. These three technologies are chosen based on the need to compare their core system of heat removing. The muffin fans are the small scale of the normal rotary fans which exploit a number of blades to produce a flow, which performs the cooling. Synthetic jets and the piezoelectric fans both use the oscillation created by a piezoelectric plate to establish a flow. The presence of an oscillating diaphragm in the synthetic jets simulates the breathing process which is done in the lungs of a human being. In the case of piezoelectric fans, the blade is being replaced with an oscillating cantilever beam which periodic movement generates a flow that eventually removes the heat. This study consists of various parts; in the first part, previously mentioned technologies are experimentally compared, in terms of their heat transfer characteristics. In order to test the technologies, an experimental system was designed and manufactured. The test system consists of two main compartments. The heat source and the cooling device; cooling devices are secured on a plexi fixture. This stand is adjustable so that the cooling device can operate in various distances. Fixtures are designed and manufactured to securely hold the devices in position, in order to avoid any extra oscillation during operation. The heat source of the test set up is a square copper heater, placed in front of the cooling technology, which is under the tests. Then, the effect of distance on the heat removal of these cooling devices are examined and reported by putting them at various distances. For the case of the muffin fan, it was observed that the heat transfer coefficient showed inverse relation with distance; higher distance exhibited low heat transfer and thus the fan was only applicable at close distances to the heater. For the synthetic jet, an optimum distance existed after which the heat transfer was not efficient. In the case of the piezoelectric fan, not only increase in the distance resulted on the low heat transfer coefficient but also the heat transfer coefficient depended on the deflection of the piezoelectric fan slab. The effect of slab deflection is studied by the use of two different materials, mylar and metallic substrate fans. The highest Nusselt number for the synthetic jet and the piezoelectric fan is around 60 while for the muffin fan this number is less than 20. The deflection of the piezoelectric slab is so crucial that in the case of the mylar slab the highest achieved heat transfer coefficient is 20 W/m2-K, while for the metallic fan it is approximately three times higher than mylar and it is about 58 W/m2-K. Beside the extensive experimental investigations, the piezoelectric fan is numerically modeled via FLUENT-ANSYS software in order to find the inaccessible results during experiments and better understanding of phenomena. The numerical results are in accordance with the experimental outcomes with a deviation of about 20 percent. The maximum velocity is found to be approximately 1.8 m/s. The flow is also being visualized by the use of the PIV imaging during the heat transfer characteristics examination of the piezoelectric fan. PIV imaging results shed light on side cooling that partially happens at the close distances. The phenomenon of the side cooling is captured after the movement analysis of more than 5000 frames of the operating maylar piezoelectric fan. It is seen that in the distance less than 5 mm there is no time for the formation of the vortex and thus the induced flow is deprived towards the sides. This means that while the heat source is coordinated in the centerline of the fan; the induced flow is cooling the heat source sides and not the heater itself. This is not desirable since the cooling efficiency is lowered at this state. Finally, a high-speed camera has also been used to capture the on spot behavior of the piezoelectric fan over the flow. With the frequency of 3000 frames per second of camera, the flow is captured by the use of a smoke pen. The vortex formation is seen within the various frequencies of the piezoelectric fan. The effect of deflection value is also captured by the sequences of the camera. The formed vortex radius is different in the case of different deflection values. Son zamanlarda çeşitli termal yönetim stratejileri ve ilgili teknolojiler, özel ihtiyaçları yerine getirmek üzerine dayanarak geliştirilmektedir. Bu teknolojilerin bazıları muffin fanları, sentetik jetler ve piezoelektrik fanlardır. Bu üç teknoloji kendi çekirdek ısı giderim sistem karşılaştırma ihtiyacını baz alınarak seçilmiştir. Muffin fanları, normal döner fanların küçük ölçeğidirler ve Soğutma yapan bir akım üretmek için bir dizi bıçak kullanırlar. Sentetik jetleri ve piezoelektrik fanların ikisi de akım oluşturmak için bir piezoelektrik plaka tarafından oluşturulan salınımı kullanırlar. Sentetik Jetlerde salınımlı bir diyafram varlığı insanın akciğerinde yapılan nefes alma işlemini simule eder. Bıçak, Piezoelektrik fanlardaki periyodik hareketi sonucunda ısıyı gideren bir akış oluşturan salınımlı konsol ışını ile değiştiriliyor. Bu çalışma çeşitli bölümlerden oluşmaktadır, birinci bölümde, daha önce bahsedilen teknolojiler deneysel olarak, ısı transfer karakteristikleri bakımından karşılaştırılmıştır. Teknolojileri test etmek için deneysel bir sistem tasarlanıp ve üretilmiştir. Test sistemi iki ana bölmeden oluşur. Isı kaynağı ve soğutma cihazı; Soğutma cihazları bir plexi fikstüre sabitlenmiştir. Bu stand ayarlanabilir, böylece soğutma cihazı çeşitli mesafelerde çalışabilir. Fikstürler, çalışma esnasında ekstra salınımı önlemek için cihazları sabit tutacak şekilde tasarlanıp ve üretilmiştir. Testin kurulumun ısı kaynağı, testlerin altında olan soğutma teknolojisinin önüne yerleştirilen kare bir bakır ısıtıcıdır. Daha sonra uzaklığın bu soğutma cihazlarının ısı gidermesi üzerindeki etkisi, çeşitli mesafelere yerleştirilerek incelenir ve raporlanır Muffin fan durumunda, ısı transfer katsayısının mesafe ile ters ilişki gösterdiği, yüksek mesafenin düşük ısı transferi sergilediği ve bu nedenle fan ısıtıcıya yakın mesafelerde uygulanabileceği görülmüştür. Sentetik jetler için, ısı aktarımı etkili olmadıktan sonra optimum bir mesafe oluşur. Piezoelektrik fan durumunda, yalnızca düşük ısı aktarım katsayısı ile sonuçlanan mesafedeki artış değil, aynı zamanda, ısı aktarım katsayısı piezoelektrik fan levhasının dönmesine bağlıdır. Levhanın dönme etkisi, mylar ve metalik substrate fanları olmak üzere iki farklı malzeme kullanılarak incelenmiştir. Sentetik jet ve piezoelektrik fan için en yüksek Nusselt sayısı 60 civarındayken, muffin fanında bu sayı 20 den düşüktür. Piezoelektrik levhanın dönmesi o kadar önemlidir ki, mylar levhasında elde edilen en büyük ısı transferi eşdeğeri 20 W/m2-K dır, metalik fan için mylar'dan yaklaşık üç kat daha yüksektir ve yaklaşık 58 W/m2-K dır. Kapsamlı deneysel soruşturmaların yanı sıra, Deneyler sırasında erişilemeyen sonuçların bulunması ve olayların daha iyi anlaşılması için, , piezoelektrik fan, sayısal olarak FLUENT-ANSYS yazılımı ile modellenmiştir. Sayısal sonuçlar, yaklaşık yüzde 20 sapma ile deney sonuçları ile uyumludur. Maksimum hız Yaklaşık 1.8 m/s olduğu bulunmuştur. Akış, piezoelektrik fanın ısı transfer özellikleri incelemesi sırasında PIV görüntüleme yöntemiyle de görselleştirilmektedir. PIV görüntüleme sonuçları, kısmen yakın mesafelerde gerçekleşen yan soğutma açıklığa kavuşturmasına yol açıyor. Yan soğutma olayı, 5000'den fazla kare maylar piezoelektrik fanın hareket analizinden sonra ele geçiyor. 5 mm'den daha az uzaklığa vorteks oluşumu için zaman olmadığı ve dolayısıyla sonuçlanan akışın yanlara doğru yoksun olduğu görülmektedir. Bunun anlamı, ısı kaynağının fan merkez çizgisinde koordine edilmesine rağmen, sonuçlanan akış ısı kaynağının yanlarını soğutulup, Isıtıcının kendisinin soğutulmamasıdır, bu durum arzu edilmez çünkü bu durumda soğutma verimi düşürülür. Son olarak, yüksek hızlı bir kamera 'da piezoelektrik fanın akış üzerindeki nokta davranışını kaydetmek için kullanılmıştır. Kameranın saniyede 3000 kare frekansıyla akış bir duman kalemi kullanılarak kaydedilmiştir. Vorteks oluşumu piezoelektrik fanının çeşitli frekanslarında görülür. Dönme değerinin etkisi kameranın dizileri tarafından da kaydedilmiştir. Oluşan vorteks etki alanı, farklı dönme değerleri durumunda farklıdır
Tracking the Persistence of Harmonic Chains: Barcode and Stability
No full textThe persistence barcode is a topological descriptor of data that plays a fundamental role in topological data analysis. Given a filtration of data, the persistence barcode tracks the evolution of its homology groups. In this paper, we introduce a new type of barcode, called the harmonic chain barcode, which tracks the evolution of harmonic chains. In addition, we show that the harmonic chain barcode is stable. Given a filtration of a simplicial complex of size m, we present an algorithm to compute its harmonic chain barcode in O(m³) time. Consequently, the harmonic chain barcode can enrich the family of topological descriptors in applications where a persistence barcode is applicable, such as feature vectorization and machine learning
Reducing root-mean-square current stress on the DC link capacitor of a five-phase electric drive through multiple carrier pulse-width modulation technique
No full textThis study investigates the angle of phase shift between interleaved carriers in pulse-width modulation, as an additional design parameter to reduce the DC link stress of a five-phase drive. Several phase shift strategies are studied and defined with a focus on the DC link root-mean-square current. The effect of adjusting the phase shift between interleaved carriers on the DC link stress is analysed and a general mathematical model is proposed to estimate the effect for any phase shift strategy. The trends predicted by simulations and analytical models have been validated through the application of the control algorithm on a five-phase motor drive system
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