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Right answer is (B) False

The best I can explain: Temporal reasoning allows a SYSTEM to reason about its operational characteristics during an interval of time. For EXAMPLE, spectrum sensing over a period can help IDENTIFY intervals of spectrum underutilization WITHIN that period of time.

The correct answer is (b) Availability of spectrum access INFORMATION to the primary user

Explanation: The wireless REGIONAL area NETWORK comprises base stations, repeaters, and consumer premise equipment. It provides fixed wireless access services in rural areas. The inclusion of a radio environment map provides knowledge of location, antenna height, transmission power, and opportunistic spectrum access. It provides knowledge DISTRIBUTION and usage patterns of secondary USERS.

Correct answer is (b) Policy life CYCLE management

For explanation: Police service is involved in the maintenance of policies that were downloaded and included in the radio frame by a policy AUTHORITY. It performs policy life cycle management operations such as PARSING the policy LANGUAGE, monitoring operation status, and eliminating OUTDATED policies.

Correct CHOICE is (b) Quality of Service

To explain: COGNITIVE radio should provide a large amount of COMPUTATIONAL resources to achieve the results of each operation. Edge conditions refer to the devices which are positioned in a location without REGULAR service and hence cannot benefit from learning techniques. Predictable behaviour refers to the ability to estimate the outcome of each step of the operation but not the final outcome.

Right OPTION is (C) SET of all possible choices

For explanation I would say: A decision tree is a DIRECTED graph with a HIERARCHICAL set of nodes and arcs. A node represents a choice or a decision. An arc from one decision node to another decision node represents all possible choices associated with that node.

Correct choice is (c) Reduction in observation time

To ELABORATE: The radio environment map holds both present and past radio environment information. Spectrum SENSING with prior knowledge is more effective than continuous SCANNING of the ENTIRE radio spectrum. Consequently, the observation time, cost, and energy consumption of radio can be REDUCED.

The correct answer is (a) Behaviour knowledge

To EXPLAIN: Behavioural knowledge involves actions and their effect on the knowledge system. Both internal and EXTERNAL effectors altering the system and the ENVIRONMENT are INCLUDED. An event begins with a set of assertions and terminates with a varying set of assertions.

The correct option is (d) Modification of knowledge BASE

The best explanation: The modification of the knowledge base step is generally the final step in a single learning CYCLE. The knowledge base is modified in accordance with the outcome of the actions implemented by the reasoning engine. The EXISTING information in the knowledge base is altered, or the action selection policy is changed. Otherwise, NEW knowledge entries are included in the database.

The CORRECT ANSWER is (d) Easy human comprehension

Easiest explanation: Symbolic knowledge representation typically involves graphical or natural language notations. It is easy for humans to UNDERSTAND. It offers a simplistic MEANS for conveying underlying information for human understanding and interpretation.

The correct choice is (C) User EQUIPMENT terminal

Easy explanation: The radio ENVIRONMENT map installed on a user’s terminal equipment is CALLED a local radio environment map. Each map is unique to its user device. The local radio environment map enables the COGNITIVE radio to store current status and past experiences.

The CORRECT answer is (a) RF environment AWARENESS

For explanation: RF awareness means to be aware of spectrum utilization, spectrum users, topology, INTERFERENCE, and other RF characteristics. Radio transceiver database, cooperative sharing, sensor networks, and field measurement are the METHODS applied to gain RF environment awareness.

Correct option is (B) GEOGRAPHICAL awareness

To elaborate: Geographical awareness provides information on TERRAIN and geographical information pertaining to radio propagation and channel PROPERTIES. Terrain recognition, site specific propagation prediction, and exploitation of geographical information database are the techniques APPLIED to gain geographical awareness.

The correct option is (c) Similarities to existing entries in memory

To explain: Learning in ontology BASED SYSTEM involves integrating new KNOWLEDGE with existing collection of entries in memory. A classifier is used to assess the degree of SIMILARITY between a new entry and the existing entries. The classifier ACCOMPLISHES this by analyzing the properties and values of a new entry.

The correct choice is (d) Learning

Best explanation: The reasoning engine is responsible for applying the GATHERED knowledge in accordance with the CURRENT state of the system. However, the reactions will be limited to previously defined knowledge even under new situations. Learning provides the ability to study input, identify patterns, and modify the operation of the RADIO system as PER the demands of the situations.

The CORRECT choice is (c) Doppler SHIFT

For explanation I would say: The major degradation introduced by channels on cognitive RADIO is shadowing, fading, and Doppler shift. Predictive models constructed using short term and long term observations with radio environment map increase awareness of channels. This helps in DEVELOPING better plans to tackle the effect of channel degradation.

Right choice is (c) Call drop due to multipath

The explanation is: COGNITIVE radio with radio environment map can predict call drop resulting due to multipath or SHADOWING. It can be prevented by switching on the backup POWER amplifier, INCREASING the number of RAKE fingers, spreading gain, changing power control policy, or by opting intersystem handoff.

Right answer is (c) Radio propagation simulation tools

The best EXPLANATION: Radio propagation simulation tools are used to predict important parameters such as path loss, signal to noise ratio, and geographical environment INFORMATION. Location specific radio propagation techniques with 3 D terrain maps offer accurate predictions that can provide BETTER system PLANNING and management.

The correct OPTION is (C) Mobility and trajectory AWARENESS

The best I can explain: Mobility and trajectory awareness COMPUTES the speed and direction of a cognitive radio. Speed and trajectory is estimated by analyzing the CHANGE of location of the radio over a period of time and by utilizing the resources of a geographic information database.

The correct choice is (a) Radio ENVIRONMENT map supports ADAPTION regardless of available resources

The best explanation: Effective adaption of radio environment map is limited by radio scenarios such as available services, user policy, radio equipment capability, and available spectrum. Radio environment map supports VARIOUS network architectures, collaborative information processing, and network ACCESS on the basis of performance metrics.

Correct answer is (C) The POLICY engine obtains the set of policies to be downloaded

Explanation: The first step in the operation of the cognition engine is to collect the set of policies to be downloaded for the operation of the radio. The policy NEXT determines the information to be MONITORED on the radio platform. Then the COGNITIVE radio grants the policy engine with the requested situational data. This results in the processing of appropriate policy rules.

Correct choice is (a) Regional licensing

Best explanation: Internet services such are live streaming sporting events, or ONLINE streaming of television shows and music might be permitted to broadcast only over certain licensed TERRITORIES. GEOLOCATION is applied to avoid license violations. Fraud detection, Geomarketing, and gaming are other regions of INTEREST.

Correct choice is (b) SUPPORTS only unidirectional communication

For EXPLANATION I would SAY: CLASS eliminates interception of packet at non-destination layer, reduces processing OVERHEAD, eliminates insertion of signaling information, and supports BIDIRECTIONAL communication. Signaling message typically includes the Internet Control Message Protocol.

The CORRECT answer is (a) Obligation policies

To ELABORATE: The Ponder language is regarded as a declarative, object-oriented language that can define obligation and authorization policies. Obligation policies are event-triggered condition-action RULES that can be used to describe adaptable management actions. Authorization policies are used to define the SET of resources available for each user access.

The correct choice is (a) METHOD of extraction of timing

For explanation: LORAN – B employed phase COMPARISON variation and HENCE used a DIFFERENT method of timing extraction compared to LORAN A. The disadvantage of LORAN B is that its pulse length was about 40 microseconds and the technique exhibited phase distortion.

The correct choice is (a) True

To explain: Cognitive radio SHIFTS communication from direct propagation to DIFFRACTED propagation. Diffracted propagation undergoes attenuation at the rate of the FOURTH power of distance. It hinders the ABILITY of the radio to SENSE, calculate interference, and evaluate the outcome of communication.

Correct option is (d) Choose MULTIPLE ACCESS techniques

Easiest explanation: MAC layer in cognitive radio should manage the level of accessibility provided for resources of the radio. MAC layer should be AWARE of channel occupancy and surrounding spectrum environment to quickly HANDLE changes in the environment and to mitigate loss PRODUCED due to mobility. MAC layer should have the capability to change design configuration.

The correct option is (d) Signal energy

To EXPLAIN: SPECTRUM reuse is a critical phenomenon that includes the OPTIMAL OPERATION of other users of the spectrum through spectrum sharing. It involves reporting the INFORMATION of spectrum usage to spectrum broker and distributing spectrum usage information to other nodes.

Right OPTION is (b) Explicit congestion notification is an extension of transport and network layer

To explain I would say: Explicit congestion notification informs about network congestion to END DEVICES without dropping PACKETS. It is possible only when the end devices and the underlying infrastructure support ECN. The procedure involves marking a bit in the IP header to indicate upcoming congestion.

The correct ANSWER is (B) Path loss is increased

Explanation: Path loss is proportional to the operating frequency. Hence, transmission range gradually REDUCES with an increase in frequency when the transmission power is not modified. If transmission power is increased, the path loss is DECREASED with an increase in the amount of interference.

Correct ANSWER is (c) Shadowing uncertainty

Best explanation: The main drawback of cooperation detection is the increased strain on NETWORKS with limited resources as the NUMBER of OPERATIONS and overhead TRAFFIC is increased. When the xG user communication range does not include the transmitter, interference is unavoidable as receiver information is unavailable. Receiver uncertainty is not solved by cooperation detection.

Correct answer is (d) Data scrubbing

For explanation: The primary source of the IP address database is the regional INTERNET registries that assign the IP addresses to organizations within their service area. Network routing information EXTRACTED at the endpoint of an IP address, data mining, and data provided by Internet Service PROVIDERS are useful for constructing the IP database.

The correct CHOICE is (d) 90 m

Easy EXPLANATION: Very high FREQUENCY omnidirectional range is a short-range radio navigation system. The signals are kept in the LINE of sight between the transmitter and receiver. It OFFERS an accuracy of 90 m.

The correct choice is (d) Reduced noise FLOOR

The best I can explain: MODULATION depth provides the degree of difference between a modulated signal and an unmodulated signal. The increase of modulation depth is a poor solution for effective spectrum usage as it increases the energy needs of the operation. It AFFECTS the operation of other spectrum users as it results in the increase of noise floor or it precludes the operation at quickly increasing RADII from the TRANSMITTER.

The correct CHOICE is (d) Increased delay

The best explanation: In the location coordination scheme, MULTIHOP paths are created, where intermediary NODES might select an identical FREQUENCY band. It results in increased switching delay. This can be avoided by INTRODUCING a scheduling mechanism such as polling.

Right option is (a) Selection of a spectrum band for transmission

Easy explanation: In multipath routing, the multiple paths are discovered first. The routes are evaluated on route metrics such as delay and link stability, and then the node selects a route for transmission. One APPROACH is to employ dynamic source routing for route discovery. Multipath routing suits the dynamic NATURE of cognitive NETWORKS and EXHIBITS increased EFFICIENCY.