Describe the roles and relationships of the members of a Chief Programmer team. [5 marks] Describe Maslow's Hierarchy of Needs. [5 marks] Discuss stages of group formation. How does belonging to a group satisfy some of the needs described by Maslow? [5 marks] "The problems of co-ordination mean that there is a limit on the size of any software system that can be successfully built." Discuss. [5 marks] 6 Advanced Algorithms Describe the structure of a Fibonacci heap and explain how to perform the following operations: (a) create an empty heap (b) add a single new node to a heap (c) form the union of two existing heaps

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Discuss how neural operators which encode, analyse and represent image structure in natural visual systems can be implemented in artificial neural networks. Include four of the following issues in your discussion: receptive field structure adaptiveness and perceptual learning hierarchies of tuning variables in successive layers of the visual pathway wavelet codes for extracting pattern information in highly compressed form self-similarity of weighting functions associative memory or content-addressable memory for recognising patterns such as faces and eliciting appropriate response sequences [20 marks] Write brief notes on each of the following: (a) the Internet Worm (b) Trojan horses (c) polymorphic viruses (d) virus exploitation of covert channels (e) the distinguishing characteristics of viruses written in interpreted languages

(a) Show that any continuous function h : D D on a domain D has a least prexed point x(h). [5 marks] (b) Let f : DE D and g : DE E be continuous functions where D and E are domains. The continuous function hf,gi : DE DE, acts so that (d,e) 7 (f(d,e),g(d,e)). Bekic's theorem states that the least xed point of hf,gi is the pair ( d, e) where d = x(d. f(d, e)) where e = x(e. g(x(d. f(d,e)),e)) . You are asked to show Bekic's theorem in the following stages. Write (d0,e0) for the least xed point of hf,gi. (i) Show that ( d, e) is a xed point of hf,gi. Deduce that (d0,e0) v ( d, e). [5 marks] (ii) Show the converse, that ( d, e) v (d0,e0). [10 marks] (a) Describe the semantics of the modal -calculus. [4 marks] (b) Describe without proof the meaning of the following modal -calculus assertions: (i) Z. hciZ ; [1 mark] (ii) Z. hciZ ; [1 mark] (iii) Z. (A([c]F hciZ)) (here F means false); [2 marks] (iv) Z. (B(AhciZ)) ; [2 marks] (v) Z. (B(AhciZ)) . [2 marks] (c) Consider the transition system consisting of two states p,q and two transitions p c q and q c p. (i) Does p satisfy Z. ([c]F (hciT hciZ)) ? (ii) Does p satisfy Z. ([c]F (hciT hciZ)) ? (Again, here F means false and T means true.) In this part you should justify your answers carefully. [8 marks]

The IA-64 architecture includes a number of instruction set features that are intended to allow compilers to generate code that will execute with fewer pipeline stalls. Explain how four of the following ve features operate, and how they could be used by a compiler to improve performance relative to more conventional instruction sequences. (a) Register windows for procedure call linkage. (b) Not a Thing (NaT) "poison" bits associated with registers. (c) Address aliasing table (ALAT) for load data speculation. (d) Register le rotation. (e) Parallel compares. [5 marks each] (a) Describe the operation of the TCP congestion control scheme, covering the two phases of slow start, congestion avoidance and the triggers of duplicate ack and timeout that set it in train. [10 marks] (b) A computer is connected to the Internet via a wireless link using the packet service from the mobile phone company. This oers 30 kbps data rate, but has a widely varying round-trip time across the wireless hop from the computer to the next hop in the backbone of between 700 milliseconds and 1.1 seconds. It also has an average packet loss rate of 25%. Using time-sequence diagrams to illustrate the fate of data packets and acknowledgements, show the impact that this has on the throughput that a typical TCP implementation would achieve. [10 marks] (a) Describe four of the problems from which classical multilevel-secure systems suer. [12 marks] (b) Your client is proposing to implement an e-mail system with the property that every e-mail sent internally within the company - that is, with no outside recipients - should be deleted after 180 days unless a manager authorises its retention. Which of the problems in part (a) would you have to consider, and why? [8 marks] (a) Specify an appropriate knot vector for each of the following NURBS curves. (i) A uniform cubic NURBS curve dened by six control points. (ii) Similar to (i) but passing through both endpoints. (iii) Similar to (i) but passing through the third control point, possibly with lower continuity at that point. (iv) The cubic Bezier curve dened by four control points. [8 marks] (b) Give the continuity class for each of: (i) curve (a)(i) between the knots; (ii) curve (a)(ii) at the knots; (iii) curve (a)(iii) at the third control point. [The continuity class is the highest derivative which is guaranteed to be continuous at the point(s) in question.] [3 marks] (c) The Loop and Buttery subdivision schemes can both operate on triangular meshes, in which all of the polygons have three sides. Both schemes subdivide the mesh by introducing new vertices at the midpoints of edges, splitting every original triangle into four smaller triangles, as shown below. Each scheme has rules for calculating the locations of the new "edge" and "vertex" vertices based on the locations of the old vertices. These rules are shown below. All weights should be multiplied by 1 16. (i) Which of the two schemes produces a limit surface which interpolates the original data points? (ii) Which of the four rules must be modied when there is an extraordinary vertex? For each of the four rules either explain why it must be modied or explain why it does not need to be modied. (iii) Suggest appropriate modications where necessary to accommodate extraordinary vertices. [9 marks] (a) Consider an interactive system with average system response time R and system throughput X. Derive the interactive response time law when there are M users present, each with an average think time Z. [6 marks] (b) Consider an interactive timesharing system with M users, one CPU and two disks labelled A and B respectively. Suppose that measurements of the system have determined that: the average user think time Z is 5 seconds; the average time spent by a job in the CPU is 40 ms per request; the average time spent by a job at the individual disks per request is 30 ms for disk A and 25 ms for disk B; the visit counts per job are 25 requests for the CPU, 20 requests for disk A and 4 requests for disk B. (i) For each of the devices: CPU, disk A and disk B, determine the service demands. [4 marks] (ii) If disk A has a utilisation of 60%, what is the utilisation of the CPU and of disk B? [5 marks] (iii) If the utilisation of disk B is 10%, what is the average response time when there are 20 users present? [5 marks] Write short notes (approximately one paragraph) explaining the similarities and dierences between each of the following: (a) Annotations and verication conditions. [5 marks] (b) Partial and total correctness. [5 marks] (c) Deep and shallow embedding. [5 marks] (d) First order and higher order logic. [5 marks] On average, how many such questions will need to be asked before the selected symbol is discovered? [2 marks] (iv) What is the entropy of the above symbol set? [2 marks] (v) Construct a uniquely decodable prex code for the symbol set, and explain why it is uniquely decodable and why it has the prex property. [2 marks] (vi) Relate the bits in your prex code to the "yes/no" questions that you proposed in (i). [2 marks] (b) Explain the meaning of "self-Fourier", and cite at least two examples of mathematical objects having this property. [3 marks] (c) Explain briey: (i) sensation limit; [1 mark] (ii) critical band; [1 mark] (iii) Bark scale. [1 mark] (d) Which dierent aspects of perception do Weber's law and Steven's law model? [2 marks]

(a) Explain how combinational and sequential devices can be modelled in higher order logic in a uniform way (i.e. so that combinational and sequential devices can be connected). [3 marks] (b) Illustrate your explanation by showing how to dene combinational devices NOT and AND that perform negation and conjunction, respectively, and a sequential unit-delay device DEL such that the output of DEL at time t+1 is the value input at t. [3 marks] (c) Dene in higher order logic a predicate Rose such that if t > 0 then Rose f t is true if and only if f has a rising edge at time t (i.e. f is true at t but false at t1). [2 marks] (d) Draw a diagram showing how to connect instances of NOT, AND and DEL to implement a device RoseImp, with one input and one output, such that the output is true at time t, where t > 0, if and only if there is a rising edge on the input at time t. [6 marks]

answer the question clearly