An autoencoder is a type of artificial neural network used to learn efficient codings of unlabeled data (unsupervised learning). An autoencoder learns two functions: an encoding function that transforms the input data, and a decoding function that recreates the input data from the encoded representation. The autoencoder learns an efficient representation (encoding) for a set of data, typically for dimensionality reduction, to generate lower-dimensional embeddings for subsequent use by other machine learning algorithms. Variants exist which aim to make the learned representations assume useful properties. Examples are regularized autoencoders (sparse, denoising and contractive autoencoders), which are effective in learning representations for subsequent classification tasks, and variational autoencoders, which can be used as generative models. Autoencoders are applied to many problems, including facial recognition, feature detection, anomaly detection, and learning the meaning of words. In terms of data synthesis, autoencoders can also be used to randomly generate new data that is similar to the input (training) data. == Mathematical principles == === Definition === An autoencoder is defined by the following components: Two sets: the space of encoded messages Z {\displaystyle {\mathcal {Z}}} ; the space of decoded messages X {\displaystyle {\mathcal {X}}} . Typically X {\displaystyle {\mathcal {X}}} and Z {\displaystyle {\mathcal {Z}}} are Euclidean spaces, that is, X = R m , Z = R n {\displaystyle {\mathcal {X}}=\mathbb {R} ^{m},{\mathcal {Z}}=\mathbb {R} ^{n}} with m > n . {\displaystyle m>n.} Two parametrized families of functions: the encoder family E ϕ : X → Z {\displaystyle E_{\phi }:{\mathcal {X}}\rightarrow {\mathcal {Z}}} , parametrized by ϕ {\displaystyle \phi } ; the decoder family D θ : Z → X {\displaystyle D_{\theta }:{\mathcal {Z}}\rightarrow {\mathcal {X}}} , parametrized by θ {\displaystyle \theta } .For any x ∈ X {\displaystyle x\in {\mathcal {X}}} , we usually write z = E ϕ ( x ) {\displaystyle z=E_{\phi }(x)} , and refer to it as the code, the latent variable, latent representation, latent vector, etc. Conversely, for any z ∈ Z {\displaystyle z\in {\mathcal {Z}}} , we usually write x ′ = D θ ( z ) {\displaystyle x'=D_{\theta }(z)} , and refer to it as the (decoded) message. Usually, both the encoder and the decoder are defined as multilayer perceptrons (MLPs). For example, a one-layer-MLP encoder E ϕ {\displaystyle E_{\phi }} is: E ϕ ( x ) = σ ( W x + b ) {\displaystyle E_{\phi }(\mathbf {x} )=\sigma (Wx+b)} where σ {\displaystyle \sigma } is an element-wise activation function, W {\displaystyle W} is a "weight" matrix, and b {\displaystyle b} is a "bias" vector. === Training an autoencoder === An autoencoder, by itself, is simply a tuple of two functions. To judge its quality, we need a task. A task is defined by a reference probability distribution μ r e f {\displaystyle \mu _{ref}} over X {\displaystyle {\mathcal {X}}} , and a "reconstruction quality" function d : X × X → [ 0 , ∞ ] {\displaystyle d:{\mathcal {X}}\times {\mathcal {X}}\to [0,\infty ]} , such that d ( x , x ′ ) {\displaystyle d(x,x')} measures how much x ′ {\displaystyle x'} differs from x {\displaystyle x} . With those, we can define the loss function for the autoencoder as L ( θ , ϕ ) := E x ∼ μ r e f [ d ( x , D θ ( E ϕ ( x ) ) ) ] {\displaystyle L(\theta ,\phi ):=\mathbb {\mathbb {E} } _{x\sim \mu _{ref}}[d(x,D_{\theta }(E_{\phi }(x)))]} The optimal autoencoder for the given task ( μ r e f , d ) {\displaystyle (\mu _{ref},d)} is then arg min θ , ϕ L ( θ , ϕ ) {\displaystyle \arg \min _{\theta ,\phi }L(\theta ,\phi )} . The search for the optimal autoencoder can be accomplished by any mathematical optimization technique, but usually by gradient descent. This search process is referred to as "training the autoencoder". In most situations, the reference distribution is just the empirical distribution given by a dataset { x 1 , . . . , x N } ⊂ X {\displaystyle \{x_{1},...,x_{N}\}\subset {\mathcal {X}}} , so that μ r e f = 1 N ∑ i = 1 N δ x i {\displaystyle \mu _{ref}={\frac {1}{N}}\sum _{i=1}^{N}\delta _{x_{i}}} where δ x i {\displaystyle \delta _{x_{i}}} is the Dirac measure, the quality function is just L 2 {\displaystyle L^{2}} loss: d ( x , x ′ ) = ‖ x − x ′ ‖ 2 2 {\displaystyle d(x,x')=\|x-x'\|_{2}^{2}} , and ‖ ⋅ ‖ 2 {\displaystyle \|\cdot \|_{2}} is the Euclidean norm. Then the problem of searching for the optimal autoencoder is just a least-squares optimization: min θ , ϕ L ( θ , ϕ ) , where L ( θ , ϕ ) = 1 N ∑ i = 1 N ‖ x i − D θ ( E ϕ ( x i ) ) ‖ 2 2 {\displaystyle \min _{\theta ,\phi }L(\theta ,\phi ),\qquad {\text{where }}L(\theta ,\phi )={\frac {1}{N}}\sum _{i=1}^{N}\|x_{i}-D_{\theta }(E_{\phi }(x_{i}))\|_{2}^{2}} === Interpretation === An autoencoder has two main parts: an encoder that maps the message to a code, and a decoder that reconstructs the message from the code. An optimal autoencoder would perform as close to perfect reconstruction as possible, with "close to perfect" defined by the reconstruction quality function d {\displaystyle d} . The simplest way to perform the copying task perfectly would be to duplicate the signal. To suppress this behavior, the code space Z {\displaystyle {\mathcal {Z}}} usually has fewer dimensions than the message space X {\displaystyle {\mathcal {X}}} . Such an autoencoder is called undercomplete. It can be interpreted as compressing the message, or reducing its dimensionality. At the limit of an ideal undercomplete autoencoder, every possible code z {\displaystyle z} in the code space is used to encode a message x {\displaystyle x} that really appears in the distribution μ r e f {\displaystyle \mu _{ref}} , and the decoder is also perfect: D θ ( E ϕ ( x ) ) = x {\displaystyle D_{\theta }(E_{\phi }(x))=x} . This ideal autoencoder can then be used to generate messages indistinguishable from real messages, by feeding its decoder arbitrary code z {\displaystyle z} and obtaining D θ ( z ) {\displaystyle D_{\theta }(z)} , which is a message that really appears in the distribution μ r e f {\displaystyle \mu _{ref}} . If the code space Z {\displaystyle {\mathcal {Z}}} has dimension larger than (overcomplete), or equal to, the message space X {\displaystyle {\mathcal {X}}} , or the hidden units are given enough capacity, an autoencoder can learn the identity function and become useless. However, experimental results found that overcomplete autoencoders might still learn useful features. In the ideal setting, the code dimension and the model capacity could be set on the basis of the complexity of the data distribution to be modeled. A standard way to do so is to add modifications to the basic autoencoder, to be detailed below. == Variations == === Variational autoencoder (VAE) === Variational autoencoders (VAEs) belong to the families of variational Bayesian methods. Despite the architectural similarities with basic autoencoders, VAEs are architected with different goals and have a different mathematical formulation. The latent space is, in this case, composed of a mixture of distributions instead of fixed vectors. Given an input dataset x {\displaystyle x} characterized by an unknown probability function P ( x ) {\displaystyle P(x)} and a multivariate latent encoding vector z {\displaystyle z} , the objective is to model the data as a distribution p θ ( x ) {\displaystyle p_{\theta }(x)} , with θ {\displaystyle \theta } defined as the set of the network parameters so that p θ ( x ) = ∫ z p θ ( x , z ) d z {\displaystyle p_{\theta }(x)=\int _{z}p_{\theta }(x,z)dz} . === Sparse autoencoder (SAE) === Inspired by the sparse coding hypothesis in neuroscience, sparse autoencoders (SAE) are variants of autoencoders, such that the codes E ϕ ( x ) {\displaystyle E_{\phi }(x)} for messages tend to be sparse codes, that is, E ϕ ( x ) {\displaystyle E_{\phi }(x)} is close to zero in most entries. Sparse autoencoders may include more (rather than fewer) hidden units than inputs, but only a small number of the hidden units are allowed to be active at the same time. Encouraging sparsity improves performance on classification tasks. There are two main ways to enforce sparsity. One way is to simply clamp all but the highest-k activations of the latent code to zero. This is the k-sparse autoencoder. The k-sparse autoencoder inserts the following "k-sparse function" in the latent layer of a standard autoencoder: f k ( x 1 , . . . , x n ) = ( x 1 b 1 , . . . , x n b n ) {\displaystyle f_{k}(x_{1},...,x_{n})=(x_{1}b_{1},...,x_{n}b_{n})} where b i = 1 {\displaystyle b_{i}=1} if | x i | {\displaystyle |x_{i}|} ranks in the top k, and 0 otherwise. Backpropagating through f k {\displaystyle f_{k}} is simple: set gradient to 0 for b i = 0 {\displaystyle b_{i}=0} entries, and keep gradient for b i = 1 {\displaystyle b_{i}=1} entries. This is essentially a generalized ReLU function. The other way is a relaxed version of the k-
Artifact (app)
Artifact was a personalized social news aggregator app that uses recommender systems to suggest articles. Launched in January 2023 by Nokto, Inc., a company founded by co-founders of Instagram Kevin Systrom and Mike Krieger, the app is available for iOS and Android. The app's name is a portmanteau of the words "articles", "artificial intelligence", and "fact". The app shut down in January 2024 as a result of low interest. == History == Nokto, Inc. was established on March 3, 2022, as a foreign stock company in California, with its headquarters in San Francisco. The company's main product, Artifact, is the first new product launched by Krieger and Systrom since their 2018 resignation from Instagram after conflicts with parent company Meta, which acquired Instagram in 2012. Artifact launched on January 31, 2023, after the team had been working on it for over a year, offering the option to sign up for a waiting list for its private beta, which grew to about 160,000 people, and then launching in open beta on February 22, 2023. With a team of seven employees in San Francisco, the app was free throughout its lifetime, with the founders explaining at the time that different business models - such as advertising or subscription fees - could be explored in the future. In January 2024, cofounder Kevin Systrom announced that the app would be shutting down after concluding that "the market opportunity isn’t big enough to warrant continued investment in this way." In April 2024, it was announced Artifact had been acquired by Yahoo, who intended to use the service's technology in an upgraded Yahoo! News app. == Features == Frequently described as "TikTok for text" and a competitor to Twitter, Artifact was a news aggregator that used machine learning to make personalized recommendations based on topics, news sources, and authors that the reader is interested in. In addition to reading articles, the app offered the ability to like articles, leave comments, or listen to an audio version of an article read by AI-generated voices, including a simulation of the voices of Snoop Dogg or Gwyneth Paltrow. AI also would rewrite clickbait headlines that users flagged. Artifact later expanded to a social network where users could post links, images and text to their profile, which could be liked or commented on by other users. Similar to other social news websites like Reddit, reader accounts had profiles with reputation scores.
Transmission security
Transmission security (TRANSEC) is the component of communications security (COMSEC) that results from the application of measures designed to protect transmissions from interception and exploitation by means other than cryptanalysis. Goals of transmission security include: Low probability of interception (LPI) Low probability of detection (LPD) Antijam — resistance to jamming (EPM or ECCM) This involves securing communication links from being compromised by techniques like jamming, eavesdropping, and signal interception. TRANSEC includes the use of frequency hopping, spread spectrum and the physical protection of communication links to obscure the patterns of transmission. It is particularly vital in military and government communication systems, where the security of transmitted data is critical to prevent adversaries from gathering intelligence or disrupting operations. TRANSEC is often implemented alongside COMSEC (Communications Security) to form a comprehensive approach to communication security. Methods used to achieve transmission security include frequency hopping and spread spectrum where the required pseudorandom sequence generation is controlled by a cryptographic algorithm and key. Such keys are known as transmission security keys (TSK). Modern U.S. and NATO TRANSEC-equipped radios include SINCGARS and HAVE QUICK.
Human rights and encryption
Human rights and encryption refers to the ways in which digital encryption affects human rights. Encryption can be used as both a detriment and a boon to human rights; for example, encryption can be used to enforce digital rights management for video games. This kind of video game licensing can render software unusable long term and represents the erosion of consumer rights. At the same time, encryption is fundamental part of internet security. Asymmetrical encryption is used extensively online for authentication, providing users confidence their internet traffic is not being misdirected. Encryption is also used to obfuscate information as it travels from end-to-end over the internet, preventing eavesdropping and tampering. Encryption can also provide anonymity, which is an important consideration for freedom of expression. Despite its drawbacks, encryption is essential for a free, open, and trustworthy internet. == Background == === Human rights === Human rights are moral principles or norms for human behaviour that are regularly protected as legal rights in national and international law. They are commonly understood as inalienable, fundamental rights "to which a person is inherently entitled simply because they are a human being". Those rights are "inherent in all human beings" regardless of their nationality, location, language, religion, ethnic origin, or any other status. They are applicable everywhere and at every time and are universal and egalitarian. === Cryptography === Cryptography is a long-standing subfield of both mathematics and computer science. It can generally be defined as "the protection of information and computation using mathematical techniques." Encryption and cryptography are closely interlinked, although "cryptography" has a broader meaning. For example, a digital signature is "cryptography", but not technically "encryption". == Overview == Under international human rights law, freedom of expression is recognized as a human right under Article 19 of the Universal Declaration of Human Rights (UDHR) and the International Covenant on Civil and Political Rights (ICCPR). In Article 19 of the UDHR states that "everyone shall have the right to hold opinions without interference" and "everyone shall have the right to freedom of expression; this right shall include freedom to seek, receive and impart information and ideas of all kinds, regardless of frontiers, either orally, in writing or in print, in the form of art, or through any other media of his choice". Since the 1970s, the availability of digital computing and the invention of public-key cryptography have made encryption more widely available. (Previously, encryption techniques were the domain of nation-state actors.) Cryptographic techniques are also used to protect the anonymity of communicating actors and privacy more generally. The availability and use of encryption continue to lead to complex, important, and highly contentious legal policy debates. Some government agencies have made statements or proposals to lessen such usage and deployment due to hurdles it presents for government access. The rise of commercial end-to-end encryption services have pushed towards more debates around the use of encryption and the legal status of cryptography in general. Encryption, as defined above, is a set of cryptographic techniques to protect information. The normative value of encryption, however, is not fixed but varies with the type and purpose of the cryptographic methods used. Traditionally, encryption (cipher) techniques were used to ensure the confidentiality of communications and prevent access to information and communications by others and intended recipients. Cryptography can also ensure the authenticity of communicating parties and the integrity of communications contents, providing a key ingredient for enabling trust in the digital environment. There is a growing awareness within human rights organizations that encryption plays an important role in realizing a free, open, and trustworthy Internet. UN Special Rapporteur on the promotion and protection of the right to freedom of opinion and expression David Kaye observed, during the Human Rights Council in June 2015, that encryption and anonymity deserve a protected status under the rights to privacy and freedom of expression: "Encryption and anonymity, today's leading vehicles for online security, provide individuals with a means to protect their privacy, empowering them to browse, read, develop and share opinions and information without interference and enabling journalists, civil society organizations, members of ethnic or religious groups, those persecuted because of their sexual orientation or gender identity, activists, scholars, artists and others to exercise the rights to freedom of opinion and expression." == Encryption in media and communication == In the context of media and communication, two types of encryption in media and communication can be distinguished: It could be used as a result of the choice of a service provider or deployed by Internet users. Client-side encryption tools and technologies are relevant for marginalized communities, journalists and other online media actors practicing journalism as a way of protecting their rights. It could prevent unauthorized third party access, but the service provider implementing it would still have access to the relevant user data. End-to-end encryption is an encryption technique that refers to encryption that also prevents service providers themselves from having access to the user's communications. The implementation of these forms of encryption has sparked the most debate since the start of the 21st century. === Service providers deployed techniques to prevent unauthorized third-party access. === Among the most widely deployed cryptographic techniques is the securitization of communications channel between internet users and specific service providers from man-in-the-middle attacks, access by unauthorized third parties. Given the breadth of nuances involved, these cryptographic techniques must be run jointly by both the service user and the service provider in order to work properly. They require service providers, including online news publisher(s) or social network(s), to actively implement them into service design. Users cannot deploy these techniques unilaterally; their deployment is contingent on active participation by the service provider. The TLS protocol, which becomes visible to the normal internet user through the HTTPS header, is widely used for securing online commerce, e-government services and health applications as well as devices that make up networked infrastructures, e.g., routers, cameras. However, although the standard has been around since 1990, the wider spread and evolution of the technology has been slow. As with other cryptographic methods and protocols, the practical challenges related to proper, secure and (wider) deployment are significant and have to be considered. Many service providers still do not implement TLS or do not implement it well. In the context of wireless communications, the use of cryptographic techniques that protect communications from third parties are also important. Different standards have been developed to protect wireless communications: 2G, 3G and 4G standards for communication between mobile phones, base stations and base stations controllers; standards to protect communications between mobile devices and wireless routers ('WLAN'); and standards for local computer networks. One common weakness in these designs is that the transmission points of the wireless communication can access all communications e.g., the telecommunications provider. This vulnerability is exacerbated when wireless protocols only authenticate user devices, but not the wireless access point. Whether the data is stored on a device, or on a local server as in the cloud, there is also a distinction between 'at rest'. Given the vulnerability of cellphones to theft for instance, particular attention may be given to limiting service provided access. This does not exclude the situation that the service provider discloses this information to third parties like other commercial entities or governments. The user needs to trust the service provider to act in their interests. The possibility that a service provider is legally compelled to hand over user information or to interfere with particular communications with particular users, remains. === Privacy-enhancing Technologies === There are services that specifically market themselves with claims not to have access to the content of their users' communication. Service Providers can also take measures that restrict their ability to access information and communication, further increasing the protection of users against access to their information and communications. The integrity of these Privacy Enhancing Technologies (PETs), depends on delicate design decisions as well as the
Media engagement framework
The media engagement framework is a planning framework used by marketing professionals to understand the behavior of social media marketing-based audiences. The construct was introduced in the book, ROI of Social Media. Powell’s background in marketing ROI and Groves' experience and understanding of the applications of social media in business led to a collaboration. Dimos joined as a brand strategist for Litmus Group, a global management consulting firm. The media engagement framework consists of the definitions of personas (Individuals, Consumers and Influencers), referenced by the competitive set or constraint that applies to that persona and the measurement framework that might be applied to those personas. It is referenced at the center of the marketing process diagram, surrounded by the marketing functions of strategy, tactics, metrics and ROI. The marketing process diagram describes how the media engagement framework can apply to any strategic marketing activity but was developed to establish a completely integrated framework describing how both traditional and social media marketing activities can be planned, executed, measured and improved. == Application == The media engagement framework provides a strategic planning construct in which measurements and metrics play a crucial role. Applying the media engagement framework aids in the development and management of an effective online marketing presence leveraging social media to engage a market or audience. By first personifying the audience, the marketer is able to identify the limiting aspect of the engagements possible with that audience segment and then, understand the type of engagement metrics to apply. Each persona makes decisions differently about how he/she acts in the social media universe. A framework metric can be applied for each of these personas: Endorsement funnel for influencers Community engagement funnel for individuals Purchase funnel for consumers Individuals, influencers and consumers make decisions based on alternatives available to them and constraints put on them. To engage with an individual brands must realize they are competing against the time an individual spends on line. If they find something else more engaging, they will engage with that activity. Brands compete against other brands for the purchases of consumers acting in the category. Lastly, influencers have only so many endorsements they can make and therefore brands compete with other endorsers for the endorsement of an influencer. Creating engaging content by keeping target audience in mind like create content that audience find it funny, interesting, and relatable will encourage audience to share it on social networks. Which will be beneficial for you brand, getting more people to know about your business and brand. Contact Digilord to create engaging content for your brand. Use of listening tools (Google Alerts, Twitter Search, SocialMention.com, Veooz.com, Alterian SM2, Radian6, Sysomos, Buzzient etc.) can be employed within the model to help identify the members of the audience segment and to support the formation of other social engagement planning and management tools.
Native cloud application
A native cloud application (NCA) is a type of computer software that natively utilizes services and infrastructure from cloud computing providers such as Amazon EC2, Force.com, or Microsoft Azure. NCAs exhibit a combined usage of the three fundamental technologies: Computational grid - loosely, e.g. MapReduce Data grids (e.g. distributed in-memory data caches) Auto-scaling on any managed infrastructure
Back-Up Interceptor Control
Backup Interceptor Control (BUIC, ) was the Electronic Systems Division 416M System to backup the SAGE 416L System in the United States and Canada. BUIC deployed Cold War command, control, and coordination systems to SAGE radar stations to create dispersed NORAD Control Centers. == Background == Prior to the SAGE Direction Centers becoming operational, the USAF deployed data link systems at NORAD Control Centers with ground computers for controlling crewed interceptors. After SAGE IBM AN/FSQ-7 Combat Direction Centrals became operational and the Super Combat Centers with improved (digital) computers were cancelled, a backup to SAGE was planned in the event the above-ground SAGE Air Defense Direction Center failed. == General Electric AN/GPA-37 Course Directing Group == BUIC began with deployment of General Electric AN/GPA-37 Course Directing Groups to several Long Range Radar stations. Units designated included the "U.S. Air Force 858th Air Defense Group (BUIC) [which became] a permanent operating facility" at Naval Air Station Fallon in Nevada. == BUIC II == BUIC II was used to command and control sites using the Burroughs AN/GSA-51 Radar Course Directing Group. North Truro AFS became the first ADC installation configured for BUIC II. == BUIC III == The AN/GYK-19 (initially AN/GSA-51A) was an upgraded version of the BUIC II system designated AN/GSA-51A and required a larger building than the AN/GSA-51. The first BUIC III site was Fort Fisher AFS, and Air Defense Command's was first installed at Fort Fisher Air Force Station, North Carolina. Although more advanced systems were contemplated, the final design of the BUIC III system was an upgraded version of the BUIC II with around twice the performance. == Closure and upgrade == In 1972, the USAF decided to shut down most of the BUIC sites; most of the sites mothballed by 1974, except for the BUIC III site at Tyndall Air Force Base. In Canada the BUIC site at Senneterre was shut down, but St Margarets remained open. The remaining sites were closed between 1983-1984 when SAGE was replaced by the Joint Surveillance System. The AN/FYQ-47 Common Digitizer for the Joint Surveillance System, and the Radar Video Data Processor (RVDP) was a combined system for the Air Force and Federal Aviation Administration (FAA), it replaced the SAGE Burroughs AN/FST-2 Coordinate Data Transmitting Sets.