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Neurochemical correlates of speed-accuracy trade-off during individual and social learning in honey bees
No full textIndividuals learn about their environment through personal observations or by observing their social conspecifics. This results in two possible learning phenotypes – slow, accurate individual learners and fast, inaccurate social learners. While the costs and benefits of these different learning strategies are recognized, the neurophysiological mechanisms that underlie such cognitive variation remain less understood. We addressed this issue by measuring individual honey bees (Apis mellifera) for their performance on an individual and a social learning task followed by quantifying the concentrations of various neurotransmitters in their brains. Our results show that during individual learning, learning speed was associated with a positive interaction between octopamine and glutamate while learning accuracy was associated with a positive interaction between octopamine and serotonin. These patterns were exactly the opposite during social learning, where learning speed was associated with a positive interaction between octopamine and serotonin and learning accuracy was associated with a positive interaction between octopamine and serotonin. We discuss the mechanistic relevance of these patterns and the idea that mechanisms underlying social learning may be distinct from those involved in individual learning and how these differences may underlie different cognitive phenotypes that form the basis of slow-fast phenotypic differences
Türk musikisi ses icrası üzerinde (yeni) İstanbul Radyosu'nun (1949-1968) rolü
Get PDFRadyo ile müziğin –birbirinden ayrı düşünülmesinin neredeyse imkânsız olduğu- bir birlikteliği, herhalde yadsınamaz bir olgudur. Resmi radyoların yayına başlamasından önce, ilk radyo yayını denemesi sırasında keman sololarının dinletildiği bir tecrübe izlenmiş, radyo bir anlamda yayın hayatına müzikle başlamış, sonrasında da müzik radyo yayınlarının en temel öğelerinden biri
olmayı sürdürmüştür. Bu seyir, dünya radyoları için böyle olduğu gibi, esasen Türkiye radyoları için de geçerlidir. Bununla beraber, bu ikisi arasında, doğalarından neşet eden bir çatışma alanını da ortaya koymak gerekir. Radyo, “tek yönlü” bir iletişim aracı olarak, ele aldığı her “konuyu” bir biçimde dinleyicisine “dikte etmeye” eğilimli bir dinamiğe sahiptir. Öyle ya da böyle, “sunduğu malzemeyi, o malzeme üzerinde oynama-değiştirme imkânı olmayan
bir kitleye iletmeyi öngören” bir yapıyı içerir. Hâlbuki müzik, kendi
iç dinamikleri olan, besteci-icracı-dinleyici unsurlarının tamamının
gelişim-dönüşüme müdahil olduğu ve bunun sosyal değişimlerle de
beslendiği, devingen bir yapıya sahiptir. Bu açıdan, bir karar merciin
belirlediği bir formu ya da normu “olduğu gibi” kabullenmeye yatkın
değildir. Bu noktada da, çatışmaya açıktır. Nitekim 1927’de yayın hayatına başlayan Türkiye radyolarında da, radyo ile musiki arasında bu “gerilimin” izlerini sürmek olasıdır. İlk iki radyo deneyiminden sonra, 1949’da kurulan ve televizyonun yayın hayatına başladığı 1968 tarihine kadar oldukça etkin bir
konumu bulunan Yeni İstanbul Radyosu’nun genelde musiki, özelde ses icracılığı üzerinde nasıl bir rolü söz konusudur? İşte bu bildiride, Radyo’nun söz konusu dönemde uygulamaya aldığı bazı kararların ses icrası üzerindeki etkileri masaya yatırılarak bu belirleyici faaliyetlerin bir değerlendirilmesi yapılacak, tüm bu uygulamaların sonucu ses icrası adına ortaya çıkan tablo analitik bir biçimde ele alınmaya çalışılacaktır
Optimal sizing and location of energy storage systems for transmission grids connected to wind farms
No full textAlthough modern renewable power sources such as solar and wind are increasing their share of the world's power generation, they need to grow faster to replace a greater share of coal and gas power generation and thus, help prevent CO2 and other greenhouse gas emissions to reach critical levels. Renewable energy generation must be coupled with energy storage systems, which are unfortunately expensive investments. However, substantial cost savings may be possible if a system-wide solution is sought. This paper presents such an attempt for a transmission grid that has a mixture of renewable and non-renewable sources. The particular problem is to find the type, location and size of the storage systems in the grid, as well as the structure of the transmission network, to minimize total investment and system-wide operating costs of power generation, transmission and storage. A mixed integer linear programming formulation is devised for the problem, which can be very large because various operational decisions are made at short intervals. Hence, we develop a “divide-and-conquer” type solution approach based on time decomposition, wherein the problem is first solved in monthly time segments. Subsequently, optimal or near-optimal monthly generation schedules are merged to construct the greater portion of a grand schedule for the whole year. Although still considerably large, the model can be solved effectively after another set of heuristically developed restrictions on the transmission network structure. The formulation and solution method are implemented on a series of realistic instances for a modest-sized transmission grid adapted from Sardinia Island of Italy to demonstrate the effectiveness of the approach and the insight into related design decisions
Cut-based matheuristic algorithms to detect tacit collusion in deregulated electricity markets
No full textIn deregulated electricity markets, the trading mechanism aims at maintaining competition among generator companies to enable just and affordable electricity prices. The relationship between generators and Independent System Operator (ISO) can be considered as a Stackelberg game formulated as a bi-level optimization problem where each generator maximizes its profit at the upper level, while ISO minimizes the cost of generation for market clearing at the lower level. Theoretically, the market is considered to be in a Nash equilibrium state under an ideal level of competition. Yet, generators could collude tacitly to obtain larger profits than they would have obtained from the largest payoff in a Nash equilibrium. In order to detect such collusions, we consider a non-linear bi-level problem formulation. The original bi-level formulation is reformulated using two alternative mixed integer linear programming formulations utilizing the linear programming property of the lower level and various linearization methods. Besides a total enumaration algorithm (based on a trivial but computationally expensive method) to detect collusions, we develop matheuristic algorithms relying on adding cuts, identification of Nash equilibrium state, partial enumeration methods and their combinations. The performance of the algorithms is compared with each other based on their capacity in identifying collusive states and the required computational effort
X-ray and gamma-ray timing of GRB 180720B, GRB 181222B, GRB 211211A, and GRB 220910A observed with Fermi and ASIM
No full textWe present a timing study of the gamma and X-ray observations and analysis of a sample of bright gamma-ray bursts (GRBs; i.e. GRB 180720B, GRB 181222B, GRB 211211A, and GRB 220910A), including the very bright and long GRB 211211A (a.k.a. kilonova candidate). They have been detected and observed by the Atmosphere–Space Interactions Monitor (ASIM) installed on the International Space Station (ISS) and the Gamma-ray Burst Monitor (GBM) onboard the Fermi mission. The early (T - T0 ≈ s) and high-energy (0.3–20 MeV) ASIM High Energy Detector (HED) and (150 keV–30 MeV) Fermi (BGO) light curves show well-defined peaks with a low quasi-periodic oscillation (QPO) frequency between 2.5 and 3.5 Hz that could be identified with the spin of the neutron star (NS) in the binary mergers originating these GRBs. These QPOs consist on the first detection of low-frequency QPOs (≤10 Hz) detected in magnetars so far. We also detect a strong QPO at 21.8-22 Hz in GRB 181222B together with its (less significant) harmonics. The low-frequency QPO would correspond to the signal of the orbiting NS previous to the final coalescence giving rise to the gravitational wave (GW) signal
Green transition for Turkey: growth, employment, and trade deficit effects
No full textThis study examines the potential economic impacts of Turkey's energy transition by focusing on the effects of solar and wind energy investments. With Turkey aiming for “net zero” emissions by 2053, this research evaluates the impacts on total emissions, economic growth, employment, and the trade deficit under various scenarios. Utilizing input-output analysis and the employment factor approach, we analyze the macroeconomic and emission outcomes of a 10-year clean energy investment project targeting the transformation of the energy sector. Our findings indicate that investing in solar and wind energy could reduce Turkey's greenhouse gas emissions by 28–77 percent of 2020 emission levels. These investments are projected to enhance economic growth, contributing an additional 0.6%–1.8% of 2020 GDP annually on average. The employment effects are also significant, with total potential job creation amounting to a total of 1.3%–3.4% of Turkey's labor force in 2020. Furthermore, the investments are expected to improve the trade balance by 6.9–14.6 billion dollars over 10 years. The results suggest that green energy investments can simultaneously achieve environmental goals and promote economic stability through job creation and improve trade balances
GPU assisted brute force cryptanalysis of GPRS, GSM, RFID, and TETRA brute force cryptanalysis of KASUMI, SPECK, and TEA3
No full textKey lengths in symmetric cryptography are determined with respect to the brute force attacks with current technology. While nowadays at least 128-bit keys are recommended, there are many standards and real-world applications that use shorter keys. In order to estimate the actual threat imposed by using those short keys, precise estimates for attacks are crucial. In this work we provide optimized implementations of several widely used algorithms on GPUs, leading to interesting insights on the cost of brute force attacks on several real-word applications. In particular, we optimize KASUMI (used in GPRS/GSM), SPECK (used in RFID communication), and TEA3 (used in TETRA). Our best optimizations allow us to try 235.72, 236.72, and 234.71 keys per second on a single RTX 4090 GPU. Those results improve upon previous results significantly, e.g. our KASUMI implementation is more than 15 times faster than the optimizations given in the CRYPTO’24 paper [ACC+ 24] improving the main results of that paper by the same factor. With these optimizations, in order to break GPRS/GSM, RFID, and TETRA communications in a year, one needs around 11, 22 billion, and 1.36 million RTX 4090 GPUs, respectively. For KASUMI, the time-memory trade-off attacks of [ACC+ 24] can be performed with 142 RTX 4090 GPUs instead of 2400 RTX 3090 GPUs or, when the same amount of GPUs are used, their table creation time can be reduced to 20.6 days from 348 days, crucial improvements for real world cryptanalytic tasks
Flow boiling of HFE-7100 over graphene coated sintered porous copper surfaces in a minichannel
No full textHigh power dense electronic devices demand efficient heat removal and thermal management. Phase change heat transfer with the application of graphene coating offers superior heat dissipation. In this study, the effects of sintered copper powders and monolayer graphene coating on flow boiling of HFE-7100 were investigated for a minichannel. Bare copper surface and surfaces with additional sintered layers of thicknesses of 0.5 mm, 1.0 mm, and 2.0 mm were compared in terms of flow boiling heat transfer. Additionally, graphene coatings were applied to each surface, and the effects of graphene coating on flow boiling heat transfer were assessed at atmospheric pressure. The experiments were conducted at different heating fluxes and two different mass fluxes (120 kg/m²s and 180 kg/m²s) for each surface. Novec HFE-7100, a dielectric fluid having a high potential for the use in electronics cooling applications, was used as the working fluid in flow boiling experiments. The results indicated that the sintered layer improved the flow boiling heat transfer performance. The sintered layer thickness of 0.5 mm offered the best heat transfer performance with an enhancement up to 145 % relative to the bare surface at high heat fluxes. It was also observed that graphene coatings further enhanced the heat transfer performance of the sintered surfaces up to 34 %. When 0.5 mm sinter thickness and graphene coating were combined, the maximum heat transfer enhancement was recorded as 227 % compared to the bare surface. In the light of high-speed camera images, flow boiling characteristics and effects of graphene coating on flow patterns were displayed. Accordingly, the graphene coating increased the nucleation site density, improved the stability of bubble formation and led to HTC enhancement for the sintered surfaces
Lyapunov-based fractional-order PID controller design for coupled nonlinear system
No full textCoupled nonlinear systems are difficult to control due to the adverse effects of uncertainties and coupling effects with increased sensor noise. This paper proposes an improved Lyapunov-based composite controller consisting of fractional-order proportional–integral–derivative (FOPID) and velocity-based disturbance observer to deal with the motion control of uncertain, nonlinear, and coupled system. FOPID utilizes the stable filtered error to facilitate the control development and stability analysis for the multi-input multi-output (MIMO) coupled system. Moreover, a disturbance observer is developed by utilizing the velocity signals to provide robustness against the disturbances and parametric uncertainties. Enhanced infinite order disturbance observer (EIFDOB) structure is used to improve the robustness of the introduced technique despite the high-frequency sensor noise. Stability analysis is provided to verify the introduced controller through the Lyapunov stability theorem, LaSalle’s invariance principle, and Barbalat’s lemma. Signal chasing is also presented to show that all signals are ultimately bounded. Comprehensive numerical simulations are performed on high-fidelity and coupled nonlinear model of the twin rotor MIMO system where the efficiency of the presented technique is examined against the external disturbances, matched uncertainties, and sensor noise. The results presented with different scenarios show that the proposed technique performed better with more robustness than FOPID and integer order proportional–integral–derivative
Comparative assessment of surface lattice resonance characteristics in plasmonic titanium nitride and gold nanodisk arrays
No full textTitanium nitride (TiN) is an advantageous material for plasmonic applications and is suitable for extreme conditions in which conventional plasmonic materials such as gold (Au) cannot be utilized. In this study, TiN and Au nanodisk arrays with different lattice spacing (Λ) were fabricated using the electron beam lithography (EBL) method to increase the quality factor of TiN. At a period of 550 nm, the TiN nanodisk arrays demonstrate a higher sensitivity, 412.79 nm·RIU−1, with the plasmonic resonance wavelength shifting from 883 nm (n = 1.3335) to 915 nm (n = 1.4069) in the NIR region. The surface lattice resonance (SLR) properties of the produced TiN nanodisk arrays were investigated in detail with Au nanodisk arrays. The TiN nanodisk arrays caused sharp plasmon resonances by creating a localized plasmon vibration mode coupled with the diffractive grazing wave excited by the incident light. The transmission dips obtained at narrower full width at half maximum (FWHM) values caused at least an almost 10-fold improvement in the quality factor compared to localized surface plasmon resonance (LSPR) dips. This study is significant for assessing the surface plasmon resonance characteristics of TiN and Au nanodisk arrays across various periods and indices