搜索结果：bulb

In a popular YouTube video by the channel Veritasium, the following question is posed: Imagine you have a giant circuit consisting of a battery, a switch, a light bulb, and two wires which are each 300,000 km long. That is the distance that light travels in one second. So, they [the wires] would reach out halfway to the Moon and then come back to be connected to the light bulb, which is one meter away. Now the question is: After I close this switch, how long would it take for the light bulb to light up: Is it half a second, one second, two seconds, 1m/c or none of the above? As part of the Physics Specialist Camp 2022 in Seifhennersdorf -- a final event of the Saxon Physics Olympiad -- students from grades 9 and 10 built a miniature model consisting of a printed circuit board and two 10-meter cables to experimentally study the question. This article describes the experimental setup, presents some exemplary results, and explains them in detail. To enable reconstruction for educational purposes, the final PCB layout, as well as the supply sources and design considerations, are provided.

This study empirically investigates firms' incentives on the choice of product durability, and its social optimality, by developing a dynamic structural model of durable goods with forward-looking consumers and oligopolistic multi-product firms. Based on the observations of the light bulb market, it specifies a model where firms produce multiple products with different durability levels and set product prices based on dynamic incentives. It proposes and applies novel estimation algorithms that alleviate the computational burden and data requirement for estimating demand and marginal cost parameters of dynamic demand models. Using light bulb market data in Japan, structural parameters are estimated. This study obtains the following results. First, large firms have incentives to collude to eliminate high durability incandescent lamps, though it is profitable to sell them for each firm. In contrast, when they can collude on prices, they don't have incentives to eliminate high durability bulbs. Second, eliminating high durability incandescent lamps leads to larger producer and total surplus, though it leads to lower consumer surplus.

With the advent of generative AI (genAI), the potential scope of artificial intelligence has increased dramatically, but the future effect of genAI on productivity remains uncertain. The effect of the technology on the innovation process is a crucial open question. Some inventions, such as the light bulb, temporarily raise productivity growth as adoption spreads, but the effect fades when the market is saturated; that is, the level of output per hour is permanently higher but the growth rate is not. In contrast, two types of technologies stand out as having longer-lived effects on productivity growth. First, there are technologies known as general-purpose technologies (GPTs). GPTs (1) are widely adopted, (2) spur abundant knock-on innovations (new goods and services, process efficiencies, and business reorganization), and (3) show continual improvement, refreshing this innovation cycle; the electric dynamo is an example. Second, there are inventions of methods of invention (IMIs). IMIs increase the efficiency of the research and development process via improvements to observation, analysis, communication, or organization; the compound microscope is an example. We show that GenAI ha

The IoT is getting more and more pervasive. Even the simplest devices, such as a light bulb or an electrical plug, are made "smart" and controllable by our smartphone. This paper describes the findings obtained by applying the PETIoT kill chain to conduct a Vulnerability Assessment and Penetration Testing session on a smart bulb, the Tapo L530E by Tp-Link, currently best seller on Amazon Italy. We found that four vulnerabilities affect the bulb, two of High severity and two of Medium severity according to the CVSS v3.1 scoring system. In short, authentication is not well accounted for and confidentiality is insufficiently achieved by the implemented cryptographic measures. In consequence, an attacker who is nearby the bulb can operate at will not just the bulb but all devices of the Tapo family that the user may have on her Tapo account. Moreover, the attacker can learn the victim's Wi-Fi password, thereby escalating his malicious potential considerably. The paper terminates with an outline of possible fixes.

The proliferation of Internet of Things (IoT) devices has raised significant concerns regarding their security vulnerabilities. This paper explores the security risks associated with smart light systems, focusing on covert communication channels. Drawing upon previous re-search highlighting vulnerabilities in communication protocols and en-cryption flaws, the study investigates the potential for exploiting smart light systems for covert data transmission. Specifically, the paper repli-cates and analyzes an attack method introduced by Ronen and Shamir, which utilizes the Philips Hue White lighting system to create a covert channel through visible light communication (VLC). Experimental re-sults demonstrate the feasibility of transmitting data covertly through subtle variations in brightness levels, leveraging the inherent functional-ity of smart light bulbs. Despite limit. ations imposed by device constraints and communication protocols, the study underscores the need for heightened awareness and security measures in IoT environment. Ultimately, the findings emphasize the importance of implementing robust security practices and exercising caution when deploying networked IoT devices

Measuring the relative humidity of air is an important challenge for meteorological measurements, food conservation, building design, and evaporation control, among other applications. Relative humidity can be measured with a psychrometer, which is a hygrometer composed of two identical thermometers. The bulb of one thermometer is covered by a wick soaked with water so that evaporative cooling makes it indicate a lower temperature than the dry-bulb thermometer; it is possible to determine the relative humidity from the difference between these readings. We describe both a model and an experimental setup to illustrate the principle of a psychrometer for a pedagogical laboratory. The science of psychrometry could be more broadly taught at the undergraduate level to help introduce students to aspects of measurement techniques, fluid mechanics, heat transfer, and non-equilibrium thermodynamics.

We present a model of a coupled system of the olfactory bulb and cortex. Odor inputs to the epithelium are transformed to oscillatory bulbar activities. The cortex recognizes the odor by resonating to the bulbar oscillating pattern when the amplitude and phase patterns from the bulb match an odor memory stored in the intracortical synapses. We assume a cortical structure which transforms the odor information in the oscillatory pattern to a slow DC feedback signal to the bulb. This feedback suppresses the bulbar response to the pre-existing odor, allowing subsequent odor objects to be segmented out for recognition.

In the light bulb problem, one is given uniformly random vectors $x_1, \ldots, x_n, y_1, \ldots, y_n \in \{-1,1\}^d$. They are all chosen independently except a planted pair $(x_{i^*}, y_{j^*})$ is chosen with correlation $ρ>0$. The goal is to find the planted pair. This problem was introduced over 30 years ago by L.~Valiant, and is known to have many applications in data analysis, statistics, and learning theory. The naive algorithm runs in $Ω(n^2)$ time, and algorithms based on Locality-Sensitive Hashing approach quadratic time as $ρ\to 0$. In 2012, G.~Valiant gave a breakthrough algorithm using fast matrix multiplication that runs in time $O(n^{(5-ω)/(4-ω)}) < O(n^{1.615})$, no matter how small $ρ>0$ is. This was subsequently refined by Karppa, Kaski, and Kohonen in 2016 to $O(n^{2 ω/ 3}) < O(n^{1.582})$. In this paper, we propose a new approach which can replace matrix multiplication tensor with other tensors. Those tensors can omit some terms one is supposed to compute, and include additional error terms. Our new approach can make use of any tensors which previously had no known algorithmic applications, including tensors which arise naturally as intermediate steps

We present a model of an olfactory system that performs odor segmentation. Based on the anatomy and physiology of natural olfactory systems, it consists of a pair of coupled modules, bulb and cortex. The bulb encodes the odor inputs as oscillating patterns. The cortex functions as an associative memory: When the input from the bulb matches a pattern stored in the connections between its units, the cortical units resonate in an oscillatory pattern characteristic of that odor. Further circuitry transforms this oscillatory signal to a slowly-varying feedback to the bulb. This feedback implements olfactory segmentation by suppressing the bulbar response to the pre-existing odor, thereby allowing subsequent odors to be singled out for recognition.

We present new smoothing techniques for topologically embedded surfaces in smooth 4-manifolds, which give topological isotopy to a smooth surface. As applications, we prove "topological = smooth" results in dimension 4 for certain disks and spheres modulo isotopy. A key step in our approach is to link Quinn's smoothing theory with ideas in Gabai's 4-dimensional light bulb theorem and succeeding developments of Schneiderman-Teichner and Kosanović-Teichner. As another application of our smoothing technique, we obtain a topological version of the Dax invariant which gives topological isotopy obstructions for topological disks in 4-manifolds.

Given n buttons and n bulbs so that the ith button toggles the ith bulb and at most two other bulbs, we compute the sharp lower bound on the number of bulbs that can be lit regardless of the action of the buttons.

The reshaping and decorrelation of similar activity patterns by neuronal networks can enhance their discriminability, storage, and retrieval. How can such networks learn to decorrelate new complex patterns, as they arise in the olfactory system? Using a computational network model for the dominant neural populations of the olfactory bulb we show that fundamental aspects of the adult neurogenesis observed in the olfactory bulb -- the persistent addition of new inhibitory granule cells to the network, their activity-dependent survival, and the reciprocal character of their synapses with the principal mitral cells -- are sufficient to restructure the network and to alter its encoding of odor stimuli adaptively so as to reduce the correlations between the bulbar representations of similar stimuli. The decorrelation is quite robust with respect to various types of perturbations of the reciprocity. The model parsimoniously captures the experimentally observed role of neurogenesis in perceptual learning and the enhanced response of young granule cells to novel stimuli. Moreover, it makes specific predictions for the type of odor enrichment that should be effective in enhancing the ability

Internet of Things (IoT) devices are progressively being utilised in a variety of edge applications to monitor and control home and industry infrastructure. Due to the limited compute and energy resources, active security protections are usually minimal in many IoT devices. This has created a critical security challenge that has attracted researchers' attention in the field of network security. Despite a large number of proposed Network Intrusion Detection Systems (NIDSs), there is limited research into practical IoT implementations, and to the best of our knowledge, no edge-based NIDS has been demonstrated to operate on common low-power chipsets found in the majority of IoT devices, such as the ESP8266. This research aims to address this gap by pushing the boundaries on low-power Machine Learning (ML) based NIDSs. We propose and develop an efficient and low-power ML-based NIDS, and demonstrate its applicability for IoT edge applications by running it on a typical smart light bulb. We also evaluate our system against other proposed edge-based NIDSs and show that our model has a higher detection performance, and is significantly faster and smaller, and therefore more applicable to a

Rear-end collision accounts for around 8% of all vehicle crashes in the UK, with the failure to notice or react to a brake light signal being a major contributory cause. Meanwhile traditional incandescent brake light bulbs on vehicles are increasingly being replaced by a profusion of designs featuring LEDs. In this paper, we investigate the efficacy of brake light design using a novel approach to recording subject reaction times in a simulation setting using physical brake light assemblies. The reaction times of 22 subjects were measured for ten pairs of LED and incandescent bulb brake lights. Three events were investigated for each subject, namely the latency of brake light activation to accelerator release (BrakeAcc), the latency of accelerator release to brake pedal depression (AccPdl), and the cumulative time from light activation to brake pedal depression (BrakePdl). To our knowledge, this is the first study in which reaction times have been split into BrakeAcc and AccPdl. Results indicate that the two brake lights containing incandescent bulbs led to significantly slower reaction times compared to the tested eight LED lights. BrakeAcc results also show that experienced subjec

We present optimized aperiodic structures for use as broadband thermal incandescent emitters which are capable of increasing the emittance by nearly a factor of two over the visible wavelength range when compared to bulk tungsten. These aperiodic multilayer structures are designed with alternating layers of tungsten and air or tungsten and silicon carbide on top of a tungsten substrate. We investigate the properties of these structures for use as lightbulb filaments. We find that these structures greatly enhance the emittance over the visible wavelength range, while also increasing the overall efficiency of the bulb and could lead to a decrease in incandescent lightbulb power consumption by nearly 50%.

In this comment on "How many principles does it take to change a light bulb ... into a laser?" by Howard M. Wiseman, Physica Scripta 91 (3), 033001 (2016) I am analyzing this extremely nicely formulated question in the framework of the Hanbury-Brown & Twiss experiment thus celebrating also its 60th anniversary. I am giving a straightforward, concise and unique answer on this question, emphasizing that the intensity correlations or the photon statistics make the difference between a light bulb and a laser.