Mobile Computing in the CloudSome mobile apps need computational power beyond their own can handle. Forexample, a mobile app uses AI to identify people. In cases like this, apps need tosend data back to the cloud letting AI services to identify the person and retrieveresults from the cloud and display on the mobile device.In general, mobile applications require cloud services for actions that can’t bedone directly on the device, such as offline data synchronization, storage, or datasharing across multiple users. People often have to configure, set up, and managemultiple services to power the backend. People also have to integrate each of thoseservices into applications by writing multiple lines of code. However, as the numberof application features grow, the code and release process become more complex,and managing the backend requires more time.AWS services such as Amplify provisions and manages backends for mobileapplications. One just selects the capabilities needed such as authentication, ana-lytics, or offline data sync, and Amplify will automatically provision and managethe AWS service that powers each of the capabilities. One can then integrate thosecapabilities into applications through the Amplify libraries and UI components

7.7.2

Mobile computing is still a very active and evolving field of research, whosebody of knowledge awaits codification in textbooks. The results achieved so far canbe grouped into the following broad areas:• Mobile networking, including Mobile IP, ad hoc protocols, and techniques forimproving TCP performance in wireless networks.• Mobile information access, including disconnected operation, bandwidth-adaptive file access, and selective control of data consistency.• Support for adaptive applications, including transcoding by proxies and adaptiveresource management.• System-level energy saving techniques, such as energy-aware adaptation,variable-speed processor scheduling, and energy-sensitive memory management.• Location sensitivity, including location sensing and location-aware systembehavior.A future in which computers become pervasive, unobtrusive, and almost invisibleis being brought a step closer. Recent development shows that demonstrator andprototype sensor networks that mark an important step forward in the cutting-edgefield.

Mobile AppsA mobile app is a software application developed specifically for use on handhelddevices such as smartphones and tablets, rather than applications running on desktopor laptop computers. Mobile apps are categorized as native apps, which are createdspecifically for a given platform, web-based apps, or web apps, which are regularweb applications that all computational works are done on the server side, or hybridapps that combines both native and web apps. Mobile apps are generally referred asnative apps. Apple iOS and Android are the most common mobile app platforms

Despite the fact that Internet computing is a relatively young concept with manyquestions still open, there is overwhelming consensus regarding the potential ofthis paradigm in advancing technology. New business solution, such as Akamaiedge computing powered by WebSphere, will enable companies to supplementtheir existing IT infrastructure with virtualized Internet computing capacity ondemand on a “pay-as-you-go” basis. A benefit of this business solution will allowdata and programs to be swept up from desktop PCs and corporate server roomsand installed in the compute Internet cloud. Implementing Internet computing willallow the elimination of the responsibility of updating software with each newrelease and configuration of desktops on installs. Since applications run in the cloudand not on individual computers or desktops, you don’t need hard drive space orprocessing power demanded by traditional desktop software. Corporations doesnot have to purchase high-powered personal computers (PC) and can purchasesmaller hard disk, less memory, and more efficient processor. Files will essentiallybe stored in the cloud, as well as software programs, and this could assist in cuttingoverhead budget substantially. The “Internet computing” trend of replacing softwaretraditionally installed on business computers with applications delivered via theInternet is driven by aims of reducing IT complexity and cost

A critical issue in implementing cloud computing is taking virtual machines,which contain critical applications and sensitive data, to public and shared environ-ments. Below are the four deployment models.• Public describes computing in the traditional mainstream sense, wherebyresources are dynamically provisioned to the general public on a fine-grained,self-service basis over the Internet, via web applications/web services, from anoff-site third-party provider who bills on a fine-grained utility computing basis.• Community shares infrastructure between several organizations from a specificcommunity with common concerns (security, compliance, jurisdiction, etc.),whether managed internally or by a third-party and hosted internally or exter-nally. The costs are spread over fewer users than a public cloud (but more than aprivate cloud), so only some of the benefits of cloud computing are realized.• Hybrid is a composition of two or more clouds (private, community, or public)that remain unique entities but are bound together, offering the benefits ofmultiple deployment models. It can also be defined as multiple cloud systemsthat are connected in a way that allows programs and data to be moved easilyfrom one deployment system to another.• Private is infrastructure operated solely for a single organization, whethermanaged internally or by a third-party and hosted internally or externally. Theyhave attracted criticism because users “still have to buy, build, and managethem” and thus do not benefit from lower up-front capital costs and less hands-on management, essentially lacking the economic model that makes cloudcomputing such an intriguing concept.

Internet computing can gain significant flexibility and agility with migratingsensitive data into remote, worldwide data centers. Integration of documents onweb-based office suites can simplify processes and creates a more efficient wayof doing business. It will allow for cost savings and easy access and streamlinemost daily activities. Internet computing powering can also support different aspectof businesses, which also utilized Internet computing with forms accessible byweb application that electronically supports online collaboration in real time withother users. The information and communication systems used, whether networkedor not, serves as a media to implement a business process. The objective of thissection is to discuss the benefits of an Internet computing environment that improvesagility, integrating modern-day technology (e.g., iPhone, iPad, web interface phone,etc.), and an example of Internet and computing online documents. It begins withan introduction of Internet computing by definition and its elements, referring tobusiness benefits of utilizing of Internet computing, examples of Internet computingsuch as web base online office suites, and the integration of Internet computing andmodern-day technology.

Ubiquitous computing is roughly the opposite of virtual reality. Where virtual realityputs people inside a computer-generated world, ubiquitous computing forces thecomputer to live out here in the world with people. Virtual reality is primarily ahorse power problem; ubiquitous computing is a very difficult integration of humanfactors, computer science, engineering, and social sciences.Augmented reality (AR) is a live, direct or indirect, view of a physical, real-world environment whose elements are augmented by computer-generated sensoryinput such as sound, video, graphics, or GPS data. It is related to a more generalconcept called mediated reality, in which a view of reality is modified (possiblyeven diminished rather than augmented) by a computer. As a result, the technologyfunctions by enhancing one’s current perception of reality. By contrast, virtualreality replaces the real world with a simulated one. An example of augmentedreality is shown in Fig. 7.13.Augmentation is conventionally in real time and in semantic context withenvironmental elements, such as sports scores on TV during a match. With the helpof advanced AR technology (e.g., adding computer vision and object recognition),the information about the surrounding real world of the user becomes interactive anddigitally manipulable. Artificial information about the environment and its objectscan be overlaid on the real world. The term augmented reality is believed to havebeen coined in 1990 by Thomas Caudell, working at Boeing.Research explores the application of computer-generated imagery in live videostreams as a way to enhance the perception of the real world. AR technologyincludes head-mounted displays and virtual retinal displays for visualization pur-poses and construction of controlled environments containing sensors and actuators.Fig. 7.13 Augmented reality (color)

Ubiquitous computing (ubicomp) is a post-desktop model of human-computerinteraction in which information processing has been thoroughly integrated intoeveryday objects and activities. In the course of ordinary activities, someone“using” ubiquitous computing engages many computational devices and systemssimultaneously and may not necessarily even be aware that they are doing so.This model is usually considered an advancement from the desktop paradigm.More formally, ubiquitous computing is defined as machines that fit the humanenvironment instead of forcing humans to enter theirs. Figure 7.12 illustrates adiagram of ubicomp.This paradigm is also described as pervasive computing, ambient intelligence,where each term emphasizes slightly different aspects.

The hardware translation from x86 instructions into internal RISC-like micro-operations, which cost relatively little in microprocessors for desktops and servers,becomes significant in area and energy for mobile and embedded devices. Hence,ARM processors dominate cell phones and tablets today just as x86 processorsdominate PCs. Atmel AVR is used in a variety of products ranging from Xboxhandheld controllers to BMW cars.

ApplicationsRISC has not got the momentum on desktop computers and servers. However, itsbenefits in embedded and mobile devices have become the main reason to be usedwidely in these areas including iPhone, BlackBerry, Android, and some gamingdevices.

Advantages and DisadvantagesThere is still considerable controversy among experts about the ultimate value ofRISC architectures. Its proponents argue that RISC machines are both cheaper andfaster and are therefore the machines of the future. Skeptics note that by making thehardware simpler, RISC architectures put a greater burden on the software. Theyargue that this is not worth the trouble because conventional microprocessors arebecoming increasingly fast and cheap anyway.To some extent, the argument is becoming moot because CISC and RISCimplementations are becoming more and more alike. Many of today’s RISC chipssupport as many instructions as yesterday’s CISC chips. And today’s CISC chipsuse many techniques formerly associated with RISC chips

The CISC approach attempts to minimize the number of instructions per program,sacrificing the number of cycles per instruction. RISC does the opposite, reducingthe cycles per instruction at the cost of the number of instructions per program

he primary goal of CISC architecture is to complete a task in as few linesof assembly as possible. A CISC processor would come prepared with a MULTinstruction. When executed, this instruction loads the two values into separateregisters, multiplies the operands in the execution unit, and then stores the product

Architecture and ProgrammingThe simplest way to examine the advantages and disadvantages of RISC architectureis by contrasting it with its predecessor: complex instruction set computers (CISC)architecture.

A reduced instruction set computer (RISC) is a type of microprocessor thatrecognizes a relatively limited number of instructions. Until the mid-1980s, thetendency among computer manufacturers was to build increasingly complex CPUsthat had ever larger sets of instructions. At that time, however, a number ofcomputer manufacturers decided to reverse this trend by building CPUs capableof executing only a very limited set of instructions. One advantage of reducedinstruction set computers is that they can execute their instructions very fast becausethe instructions are so simple. Another, perhaps more important advantage, is thatRISC chips require fewer transistors, which makes them cheaper to design andproduce. Since the emergence of RISC computers, conventional computers havebeen referred to as CISCs (complex instruction set computers).6.4.1 HistoryThe first RISC projects came from IBM, Stanford, and UC-Berkeley in the late1970s and early 1980s.

Computers with multiple processors located in a central location or distributedlocations are generally considered as a parallel processing system (Hwang 1993).Here multiple processors mean multiple processing units. It is different from multi-core computers that we have just discusse

For a MIMD system, each processor has its own cache memory. They alsoshare the main memory, storage, and I/O devices in order to share data among theprocessors.

Front-side bus (FSB) functions as the processor bus, memory bus, or system busthat connects the CPU with the main memory and L2 cache.

Dual-channel architecture requires a dual-channel-capable motherboard and twoor more DDR, DDR2 SDRAM, or DDR3 SDRAM memory modules.

Fewer people have studied the vulnerabilities of computer buses to attackers. Acomputer system can be taken over from devices that are attached to the buses

Figure 4.6 shows that there are many buses in a computer system. If we look intoit, we can see that it is essentially a single-bus system. In addition to the PCI bus,the AGP is merely a graphics accelerator. It goes through a bridge that bridges AGPand PCI together. Similarly, SATA and USB also go through a bridge that exchangesignals between SAT

As a multi-core (quad-core or more) computer contains two or more processorsintegrated on one chip, people would think this is a multi-bus system.

A bus is usually referred to as address, data, and control signals that connect to aprocessor. An actual computer may have more buses than just only one single bus

Asynchronous communication utilizes a transmitter, a receiver, and a wirewithout coordination about the timing of individual bits

Synchronous Bus and Asynchronous Bus

MIDI controllers are also available in a range of other forms, such as electronicdrum triggers, pedal keyboards that are played with the feet (e.g., with an organ),wind controllers for performing saxophone-style music, and MIDI guitar synthe-sizer controllers.

MIDI∗Musical instrument digital interface (MIDI) is an electronic musical instrumentindustry specification that enables a wide variety of digital musical instruments,computers, and other related devices to connect and communicate seamlessly withone another.The primary functions of MIDI include communicating event messages aboutmusical notation, pitch, velocity, control signals for parameters such as volume,vibrato, audio panning, cues, and clock signals (to set and synchronize tempo)

Ethernet is a family of computer networking technologies for local area networks(LANs) commercially introduced in 1980. Standardized in IEEE 802.3, Ethernethas largely replaced competing wired LAN technologies.Systems communicating over Ethernet divide a stream of data into individualpackets called frames. Each frame contains source and destination addresses anderror-checking data so that damaged data can be detected and re-transmitted.The standards define several wirings and signaling variants. The original10BASE5 Ethernet used coaxial cable as a shared medium. Later the coaxialcables were replaced by twisted pair and fiber-optic links in conjunction with hubsor switches. Data rates were periodically increased from the original 10 megabitsper second to 100 gigabits per second

Parallel Buses and Parallel CommunicationIn telecommunication and computer science, parallel communication is a methodof sending several data signals simultaneously over several parallel channels. Itcontrasts with serial communication; this distinction is one way of characterizinga communications link

In telecommunications, RS-232 is the traditional name for a series of standardsfor serial binary single-ended data and control signals connecting between a data

trol signals in the control bus:• Clock The clock signal (usually represented as φ) is used to synchronize memoryand other devices with the processor. Some instructions only need one cycle (suchas shift, logical bit operations), while others may require more cycles to performthe instruction. For a processor with the clock frequency f , the cycle T = 1/f .• Reset Reset signal will initialize the processor. It is usually referred to as warmreboot. Many computers come with a reset button. In the event the system isfrozen, a warm start usually can solve the problem.• Read/Write The R/W signal is used to communicate with the memory or I/Odevices to send or receive data to or from the CPU.• Interrupt The interrupt signal is used to indicate if there is a device requestingdata exchange with the CPU. There is also an acknowledgement (ACK) signalthat tells the device if the request has been granted.

For a 32-bit processor, theaddressing space is 4 G

A system bus consists of three sub-bus systems, an addressbus, a data bus, and a control bus.

Compared with RFID, NFC has a much closer contactless distance,so it is more secure.

The normal data exchangerange of NFC is about 10 cm, which makes NFC a more secure way to transferhigh-speed data

Near field communication (NFC) is a technology that generally replaces the stan-dard practice of typing in a username and/or password; multifactor authenticationusing NFC can be used in conjunction with either or both.

The RFID tag then sends out its unique ID number (storedin built-in memory).

RFID options for young kids

A cloud server

More efficient student attendance—System automates the student attendance,hence reducing irregularities in the attendance process arising due to human error.

The system has an built-in facility of sending automatic SMS and E-mail alerts to Parents/Guardians of students.

The student attendance system we aretrying to build is a biometrics and RFID-based attendance management system forschools.

Fixed readers are set up to create a specific interrogation zone which can betightly controlled.

the halting problem represents the associated function as w

unction is what specifies the correspondence between elements in two sets.A function that defines the correspondence of elements of sets A to those of Bis denoted by f : A → B, and the element of B corresponding to an element a of Ais denoted by f (a), where a is said to be mapped to f (a). A function is also calleda mapping. The set A of

ing is a sequence of symbols, which will be discussed frequently throughoutthis book. Suppose we are given a finite set of symbols. The strings we deal withare assumed to be composed o

A is called the size of set A and is denoted by |A|. A set whose size is zero is calledan empty set and denoted by ∅. That is, ∅ denotes a set that has no elements. If ais an element of se

e Cartesian product is frequently used in this book, the readersare expected to have a firm image of it mind. The Cartesian product can be general-ized for an arbitrary number of sets. For example, A × B × C = {(a, b, c) | a ∈ A,b ∈ B, c ∈ C}. In particular, the Cartesian product of k As A × A × · · · × A is de-noted by A k . In general, an element of Ak , denoted by (a 1 , a 2 , . . . , a k ), is calleda k-tuple. In particular, an element o

Much research has been done on quantum computers, whichutilize effects related to quantum mechanics, and on neurocomputers, which havea neuron-like structure as well. The computational barriers might be overcome bymeans of the effect of the superposit

Von Neumann (1903–1957), who should be acknowledged as the originator of computer science and whois a titan in this field, is also known for having devised the stored-program conceptused by present day computers. Touching upon computer design, von Neumannhighlights the contrast between computers and humans and

In the case of context-free grammars, a rewriting rule can always be appliedprovided that a symbol, corresponding to the term on the left-hand side of therule, appears in a generated string. In other words, the rewriting does not dependon the surroundings, i.e., context.

nce for the robustness of the Turing machine computational model, thereis not only the fact that the computational power does not change in accordancewith the model parameters, but also the fact that what can be computed does notchange even if we adopt, instead of a Turing machine, a superficially dissimilarcomputational model that is defined in terms of funct

eal with a variety of computational models: a pushdown automa-ton created by replacing a tape of a Turing machine with one of restricted read-writefashion; a finite automaton obtained by replacing a tape of a Turing machine by aread-only tape of finite leng

lthough many researchers conjecture that an NP-completeproblem cannot be computed in polynomial time, it has not yet been proved whetherthis conjecture is valid or not. The problem to prove or disprove the conjecture issaid to be the P vs. NP problem, which remains as the greatest unsolved problemof computer science

problem which is computable inpractice is considered to be one whose time complexity is described as a functionpolynomial in input size n, whereas a problem that is not computable in practiceis one whose time complexity is greater than any function polynomial in n,

Turing asserted that what can be computed by a mechanical procedure is equiva-lent to what can be computed by a Turing machine. This is called the Church–Turingthesis, which asserts that the intuitive concept of being computable by a mechanicalprocedure is equivalent to the precise notion defined mathematically in terms of aTuring machine.

a Turing machine is built from a control part and a tapeof infinite length, which is divided into squares. The tape works as memory, whereasthe control part, taking one of a finite number of states, controls how to read orrewrite a symbol on the square that the control part looks at currently.

Computational Barrier

Furthermore,although a program exists that has enabled a computer to win against the master ofchess, no such program that reaches the level of chess exists for shogi or go. Thereason is that, in general, as the depth of reading ahead in a game increases, thenumber of cases that must follow increases explosively. In this respect, computerscannot yet cope well with shogi and go, as they can with chess. We must confron

Computer science deals with the issue of what can and cannot be computed and,if possible, how it can be computed. We refer to what a computer does, whateverit is, as “computation.”

What isdefined as a field within which an algorithm works is a computational model. Oncea computational model is defined, a set of basic moves that are performed is fixed asone step.