Question: Algorithms (a) Explain the greedy strategy in algorithm…

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Question Answered step-by-step Question: Algorithms (a) Explain the greedy strategy in algorithm… Question:Algorithms (a) Explain the greedy strategy in algorithm design. To what problems does it apply? [3 marks] (b) If a problem can be solved with both dynamic programming and a greedy algorithm, what are the adv of up to a given amount of p pence. Its goal is to minimize the number of postage stamps issued, and the machine always has as many stamps as needed. (i) Let the set of available denominations for the stamps be D = {1p, 5p, 25p, 50p, £1, £2}. Can this problem be solved using bottom-up dynamic programming? If so, clearly describe your algorithm and determine its complexity. If not, prove that it cannot be done. [5 marks] (ii) Let c1 < c2 < · · · < cn be n stamp denominations. Prove that if each ci (a positive integer) is a multiple of ci−1 for every i = 2, . . . , n then the greedy strategy applied to the set D = {c1, c2, · · · , cn} finds the optimal solution for any amount p that is a multiple of c1. [7 marks] (iii) Provide a set of denominations for stamps D and an amount of pence p for which the greedy strategy fails to give an optimal solution, p being a multiple of the smallest denomination in D. Show what solution the greedy strategy would find and what the optimal solutiony-list representation and the adjacency-matrix representation. Find a problem that can be solved more efficiently in the adjacency-list representation than in the adjacency-matrix representation, and another problem that can be solved more efficiently in the adjacency-matrix representation than in the adjacency-list representation. [4 marks] (b) Prove or disprove (by giving a counter-example) the following claim: If a directed graph G contains a path from a vertex u to a vertex v, then any depth-first search must result in v.d ≤ u.f, where .d is the discovery time and .f the finishing time. [4 marks] (c) We are given an undirected, connected graph G = (V, E) with edge-weights w : E → R + and a minimum spanning tree T of G. How would you update your minimum spanning tree T in each of the following three cases? Specify the runtime of your algorithm and give a proof that the returned tree is indeed a minimum spanning tree. (i) We increase the weight of an edge e which is not in T. [3 marks] (ii) We decrease the weight of an edge e which is in T. [3 marks] (iii) We add a new edge e with weight w(e) to G. The weight w(e) is arbitrary, but for simplicity you may assume that after adding the edge e no two edges in G have the same weight. Assuming both operands are normalised and nonzero, what is the maximumdegree (number of shifts) of normalisation required in the result of a floatingpoint multiplication? Ignore zero and denormal results. [5 marks](b) A watertight capsule containing scientific instruments is dropped from ahigh-altitude plane into the ocean where it must approach close to the sea bottombefore floating up for retrieval by a boat. You are provided with subroutinesthat compute water and air resistance from velocity. Collision with the oceanbottom is a mission failure.(i) Set up a state vector and sketch code for a finite-difference, time-domainsimulation of the trajectory in one dimension. Include a check for missionfailure. [5 marks](ii) What three issues will affect your choice of simulation timestep?[3 marks](iii) Your simulation is now re-coded using interval arithmetic. New subroutinesfor resistance are provided with interval domain and range giving a pair withthe maximum and minimum resistance likely to be encountered. All inputparameters are likewise coded as pairs. Summarise how this will affect thestate vector and your code  The Java class below defines a queue data structure with a fixed capacity. public class FixedCapacityQueue { int[] mData = null; int mHead=0; // index of first full cell int mTail=0; // index of next empty cell public FixedCapacityQueue(int capacity) { mData = new int[capacity]; } public boolean enqueue(int x) { if (mTail==mData.length) return false; mData[mTail]=x; mTail++; return true; } public int dequeue() { if (mTail==mHead) return -1; int v=mData[mHead]; mHead++; return v; } } (a) Explain the risks posed by the lack of access modifiers specified on the state. Which access modifier is appropriate for these entities? [3 marks] (b) Discuss the choice to signal enqueue and dequeue errors using return values of false and -1, respectively. Suggest a better alternative and modify enqueue and dequeue to use it. [5 marks] (c) Explain how an enqueue operation on a FixedCapacityQueue object could fail with an error even when there are fewer items in the queue than the assigned capacity of the object. Show how to fix this. [3 marks] (d) Rewrite the class to use Java's Generics so that it can be used to represent queues of arbitrary objects (Integers, Strings, etc). Use the java.util.ArrayList class instead of int[] for the type of mData. [4 marks] (e) Explain why it was necessary to replace the int[] type of mData in part (d), and why ArrayList does not suffer from the same issue. [5 marks] 3 (TURN OVER) CST.2015.1.4 4 Object-Oriented Programming A developer wishes to create a photo library application that can auto-detect faces in images to assist labelling. They wish to use some commercially available Java face detection software. The source to this software is unavailable—only the Java bytecode and documentation are supplied. The two key classes are as follows: Class name Method prototype Image // Constructor public Image(byte[] imageData, int w, int h) // Get the image value at pixel (x,y) public byte getPixel(int x, int y) // Set the image pixel at (x,y) to value val public void setPixel(int x, int y, byte val) // Get the image width public int getWidth() // Get the image height public int getHeight() Algorithm // Search for and mark the faces in Image im public static void markFaces(Image im) (a) Explain what is meant by source code, machine code and Java bytecode. Give two advantages of distributing Java software as bytecode rather than source code. [5 marks] (b) Explain why markFaces() is declared static. [1 mark] (c) The developer wishes to add filename information in the form of a String to all of the Image instances. Show how to achieve this efficiently using inheritance. [4 marks] (d) The developer wishes to know whether the markFaces() method visits every pixel in the image or uses a more intelligent search strategy. Provide a new class definition that can be used to determine the search sequence. Your class should be able to temporarily augment an Image object with logging capabilities while it is being processed by markFaces(). [Hint:   Explain how shared data can be protected through the use of objects. [8 marks] The built-in facilities for restricting concurrency in Java allow only one thread at a time to be executing within the critical region.readers may share access at the same time, but only one writer may acquire exclusive access (excluding any readers while it does so). Specify a MultiSync class in Java with methods to acquire and release both read and write access, and sketch its implementation. [6 marks] Derive a MultiBuffer class that extends MultiSync with methods to store and read a data field, ensuring that any locks are released when a waiting thread is interrupted. Your example may use a simple data field such as an integer but you should explain why such an elaborate scheme of concurrency control is unnecessary in this case. [6 marks] 2 CST.99.4.3 4 Compiler Construction It is commonly suggested that Algol-60 call-by-name can be modelled by passing a function as a call-by-value parameter. Show how a program containing a definition int f(int x:name) { ... x ... x ... } of f (where x occurs only in Rvalue context) and a call f(e) to f can be replaced by an equivalent definition and call using only call-by-value. [6 marks] Most such explanations assume that the uses of x within f occur only in Rvalue context. However, Algol-60 also permits the equivalent of int g(int x:name) { if (p) { ... x := x+1; x := -x; ... } return x; } and calls like g(a[k()]) which, when p is true, would have the effect of calling k() five times and consequent access to five (possibly different) subscripts of array a[]. Develop your explanation for the first part of this question to cover also the case of a call-by-name parameter being used in both Lvalue and Rvalue contexts. [Hint: note that when p is false then the actual parameter to g need not be an Lvalue, so you may need two parameterless procedure arguments ("thunks").] [8 marks] Using the previous part or otherwise, give a translation of a definition and call h(e) using call-by-value-result (Ada in out mode) with no uses of the address-of (&) operator other than those involved in call-by-name. Your explanation is allowed to deviate from call-by-value-result by allowing side-effects in e to take place twice. [6 marks] 5 Data Structures and Algorithms Outline the mechanism used in the Burrows-Wheeler block compression algorithm, illustrating your description by applying it to the string ALFALFA. [14 marks] Briefly discuss the advantages and disadvantages of the Burrows-Wheeler algorithm compared with other commonly used compression methods. [6 marks] 3 [TURN OVER CST.99.4.4 6 Computer Design A modern processor's memory is constructed from a hierarchy of memories. Explain what the levels of the hierarchy are. [5 marks] Why do modern processors have several registers rather than an accumulator plus one or two index registers? [5 marks] Hand compile the following pseudo-code for both a register machine and an accumulator machine of your choice. You may invent an instruction set. Make the semantics of the code clear via comments. a=0; b=1; for(i=0; i<5; i++) { a=a+b; b=a-b; } [10 marks] 7 Operating System Functions The following are three ways which a file system may use to determine which disk blocks make up a given file. (a) chaining in a map (b) tables of pointers (c) extent lists Briefly describe how each scheme works Additional hint on notation: s u = path from s to u consisting of 0 or moreedges (0 when s ≡ u); u → v = path from u to v consisting of precisely oneedge; d[u] = weight of the shortest path found so far from source s to vertexu; δ(s, v) = weight of shortest existing path from s to v.](c) Why does the algorithm require non-negative edge weights? [2 marks](d) Would the algorithm work if the only negative weights were on edges leavingthe source? Justify your answer with a proof or counterexample. [5 marks](e) Consider the following approach for finding shortest paths in the presence ofnegative edges. "Make all the edge weights positive by adding a sufficientlylarge biasing constant to each; then find the shortest paths using Dijkstra'salgorithm and recompute their weights on the original graph." Will this work?Justify your answer with a proof or counterexample. [3 marks]2CST.2006.5.32 Computer Design(a) Why do pipelines exhibit branch and load delays? [6 marks](b) What impact does pipeline length have on clock frequency? [4 marks](c) Why might a shorter pipeline result in a more power-efficient design?[4 marks](d) Recently we have seen microprocessor manufacturers release dual-processorchips where each processor has a shorter pipeline than the earlier singleprocessor per chip designs. What sort of applications might run better onthe older chips and vice versa? [6 marks]3 Digital Communication I(a) Describe the concepts of circuit switching and packet switching. [5 marks](b) What are the fundamental advantages of each over the other? [5 marks](c) What is the role of buffering and buffering policy in each approach? [5 marks](d) There is an expectation that in the near future telephony will move from circuitswitching to packet switching. Why is this so in light of the advantages of eachapproach? [5 marks]3 (TURN OVER)CST.2006.5.44 Concurrent Systems and Applications(a) The following Java interface describes the API for a first-come, first-served(FCFS) mutual exclusion system, designed to work even if threads areinterrupted in the enter and exit routines.interface FCFS {public void enter();public void exit();}Sketch a concrete class, FCFSImpl, implementing this interface, which does notneed to be re-entrant, ensuring that you satisfy the following requirements:(i) if a thread is interrupted while executing the entry protocol, it shouldabort its attempt to gain entry and cleanly terminate the call; you mayassume that the calling code will not then enter the critical region;[6 marks](ii) the exit protocol should notify a particular thread and not simply callnotifyAll(). [6 marks](b) Object allocation graphs can be used to detect deadlock in a concurrentapplication.(i) Give an example of an object allocation graph and explain the meaningsof the different components. [2 marks](ii) Describe an algorithm which can use an object allocation graph and anobject request matrix to determine whether or not deadlock exists.[5 marks](iii) Describe how to distinguish between cases in which deadlock has occurredand those in which deadlock is inevitable but is yet to occur. [1 mark]4CST.2006.5.5SECTION B5 Computer Graphics and Image Processing(a) Give the definition of the cubic Be0zier curve. [4 marks](b) Derive the conditions necessary to ensure that two cubic Be0zier curves joinwith C1-continuity. [6 marks](c) Describe, in detail, an algorithm for drawing a cubic Be0zier curve to a giventolerance using straight lines. You may assume that you already have analgorithm for drawing a straight line. [6 marks](d) Explain why and how homogeneous co-ordinates are used in computergraphics. [4 marks]6 Compiler Construction(a) Consider the grammarS ::= (L) | aL ::= L, S | S(i) Present a right-most derivation for the string (a, ((a, a), (a, a))).[3 marks](ii) Present a left-most derivation for the same string (a, ((a, a), (a, a))).[3 marks](b) Automatic garbage collection is an important technique for the implementationof many programming languages. Define each of the following variations:(i) Mark and Sweep; [3 marks](ii) Copy Collection; [3 marks](iii) Generational Collection. [3 marks](c) Write a small program that will produce different values depending on whichkind of variable scoping mechanism is used, static or dynamic. Explain youranswer. [5 marks]5 (TURN OVER)You may find it useful to apply a common design pattern.] [10 marks] 4 CST.2015.1.5 SECTION C 5 Numerical Methods (a) Consider the iteration: xn+1 = (2xn + N/x2 n )/3 (i) The iteration converges to give what useful property of the constant argument N? [2 marks] (ii) Examine whether the above iteration should work for all possible values of N and x0? [6 marks] (iii) Find the order of convergence for the above iteration. You may use standard results but do not simply state an order without justification. [3 marks] (b) Cholesky provides an approach to solving certain systems of simultaneous equations. His method (and similar methods) perform upper/lower triangle decomposition of the equation coefficient matrix A such that A = LU and U T = L. (i) Under what circumstances can Cholesky's method be used? Can it be used if A is already a triangular matrix and, if not, what should be done instead? [3 marks] (ii) Give expressions for two of the four values in the upper-left 2×2 sub-matrix of L in terms of the elements of AImage transcription textflat h) - f(a) = 3. h Practice consider f(x) = 9x - 5. a. Compute: f(a) = b.Compute and simplify: f(a ... Show more... Show moreImage transcription textGiven 100 G3 =—, U s2+10/§3+100 do each ofthe following: 3 Compute can (Natural frequency)b Compute C (Damping ratio) c Co... Show more... Show more  Computer Science Engineering & Technology C++ Programming COMPE COMPE375 Share QuestionEmailCopy link Comments (0)

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Question Pro: Stern, S. W., (2019). Sex workers of the world unite. The American Scholar, pp. 40-54. The author presents the case, largely though the words of sex-workers themselves, for de-criminalization and for allowing sex workers to control the conditions of their work—that is, to operate brothels themselves, choose their physicians, provide and receive benefits, and work outside brothels if they so choose - which will make them safer and less apt to be exploited.Con: Der Spiegel Staff. (2013, May). How legalizing prostitution has failed. Der Spiegel Online. https://www.spiegel.de/international/germany/human-trafficking-persists-despite-legality-of-prostitution-in-germany-a-902533.htmlStaff writers report that since de-criminalization of prostitution in Germany in 2003, exploitation and human trafficking remain significant problems. According to one German law enforcement officer, Germany is a "center for the sexual exploitation of young women from Eastern Europe, as well as a sphere of activity for organized crime groups from around the world" (Germany's Human Trafficking Problem section)Aspect 2: SESTA/FOSTA.What other emotion is Sarah displaying? (1 mark)________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________5. What action is appropriate for the PSW to take in this situation? Why? (3 marks)________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Today is your day off. You find yourself in the Ross' neighbourhood and decide to say hello. As you go up to the door, you see Mrs. Ross violently shaking her son. She is visibly upset and is speaking to him in a very angry voice.1. Describe all the feelings that you (or other PSWs) might have in this situation. Explain how they might be helpful or unhelpful in resolving the problem. (2 marks)________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________  2. Identify the possible reasons for the angry outburst in Mrs. Ross. (3 marks)________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________3. Identify two behaviours in Ray that indicate that he may be abused. (2 marks)a.______________________________________________________________b.______________________________________________________________ 4. What action is appropriate for the PSW to take in this situation? Why? (3 marks)________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Perhaps, however, there might turn out to be gene control networks that do generally structure certain features of the psychological development of contemporary humans (Walsh 2006: 440ff.). The quest for such GNRs can, then, count as the search for an explanatory nature of contemporary humans, where the explanatory function thus sought is divorced from any classificatory role.Aspect 1: SafetyPro: (citation to article supporting SESTA legislation; brief description of content)Con: (citation to article against SESTA legislation; brief description of content)Aspect 3: EconomicsPro: (citation to article showing better income/standard of living after de-criminalization; brief description of content)Con: (citation to article showing real economic benefit is to pimps, traffickers brief; description of content)My Topic Selection: TelehealthIssue: What are the positive and negative impacts of Telehealth in the over-all delivery of care?Aspects:1. Legal aspects2. Financial aspects3. Medical aspectsExplanation:The healthcare sector has been in a more intense battle than ever before since the pandemic begun. This sector has been finding ways on how to navigate the times just to deliver the best care possible to the public. Telehealth is an interesting topic to explore given the times we are in - the digital era. Understanding the positive and negative impacts of Telehealth in the over-all delivery of care will help us innovate and create better systems where there are weaknesses while we build-up on the strong points.Aspects:1. Legal aspectsWhat could be the potential professional disadvantage on the side of the practitioner in utilizing Telehealth? What are the policies and guidelines that have been developed for Telehealth? Issues on confidentiality and IT security may also be taken into consideration.2. Financial aspectsHow does the Telehealth affect the medical coverage/insurances? 3. Medical aspectsHow effective is the assessment of the healthcare provider? For instance, howcan they assess breathing? Or how can they take the baseline vital signs? Do they have alternatives for Telehealth consultations in assessing the patients?There has, however, been a move in general philosophy of science that, if acceptable, would transform the relationship between the taxonomic and explanatory features of species. This move was influentially initiated by Richard Boyd (1999a). It begins with the claim that the attempt to define natural kinds in terms of spatiotemporally unrestricted, intrinsic, necessary and sufficient conditions is a hangover from empiricism that should be abandoned by realist metaphysics. Instead, natural kinds should be understood as kinds that support induction and explanation, where generalisations at work in such processes need not be exceptionless. Thus understood, essences of natural kinds, i.e., their "natures", need be neither intrinsic nor be possessed by all and only members of the kinds. Instead, essences consist of property clusters integrated by stabilising mechanisms ("homeostatic property clusters", HPCs). These are networks of causal relations such that the presence of certain properties tends to generate or uphold others and the workings of underlying mechanisms contribute to the same effect. Boyd names storms, galaxies and capitalism as plausible examples (Boyd 1999b: 82ff.). However, he takes species to be the paradigmatic HPC kinds. According to this view, the genealogical character of a species' nature does not undermine its causal role. Rather, it helps to explain the specific way in which the properties cohere that make up the taxon's essence. Moreover, these can include extrinsic properties, for example, properties of constructed niches (Boyd 1991: 142, 1999a: 164ff.; Griffiths 1999: 219ff.; R. Wilson et al. 2007: 202ff.).How would a nurse integrate these teaching tools into daily nursing practice?• Which tools are the most effective?• Do the resources reach across the lifespan?• Is the use of social media effective?Whether such an account can indeed adequately explain taxonomic practice for species taxa is a question that can be left open here (see Ereshefsky & Matthen 2005: 16ff.). By its own lights the account does not identify conditions for belonging to a species such as Homo sapiens (Samuels 2012: 25f.). Whether it enables the identification of factors that play the explanatory roles that the term "human nature" might be supposed to pick out is perhaps the most interesting question. Two ways in which an account of human nature might be developed from such a starting point have been sketched.Mutual patterning of the human and environmental fields includes:• sharing knowledge• offering choices• empowering the patient• fostering patterning• evaluation• repeat pattern appraisal, which includes nutrition, work/leisure activities, wake/sleep cycles, relationships, pain, and fear/hopes• identify dissonance and harmony• validate appraisal with the patient• self-reflection for the patientAsha Singh is a 49-year-old woman who recently moved from Southern India.  Asha has found moving to a new country challenging, she has struggled with the cultural change and has found it hard to settle into her new environment. She moved to Australia to a moderate size rural township, with her husband Rahul and their three school aged children, Arman (16), Panav (14) and Anaya (13). They all attend the local high school. The children have settled into school well and her husband has started his new job, Asha finds herself alone and isolated, as she has not developed friendships at this point in time. The rest of her family are assimilating well into the new country and home. Asha was woken overnight with an unusual heavy feeling in her chest, she ate late the evening before so thought it may have just been a little indigestion. She felt anxious but this feeling of anxiety has been with her a lot lately, and was also finding it difficult to breath, she put this down to her anxiety and fell back to sleep. The following morning she woke without pain and did not mention anything to her husband as she did not want to worry him and carried on with her morning. As the morning progressed she was busy tidying the house and preparing the evening meal. The pain in her chest returned, this time it felt very heavy and she started to feel dizzy, anxious and was having difficulty breathing. She decided to call her husband, he called an ambulance and left work to be with his wife. Asha was transported to hospital, she was diagnosed with a having a ST Elevated Myocardial Infarction (STEMI). Asha has a medical history of hypertension, she is also overweight and has never enjoyed exercise. Her new doctor has started her on Ramipril 5mg nocte, she has been compliant with her medication as both her parents had high blood pressure and they both have died from cardiac disease. Asha is a non-smoker and eats a very traditional Indian diet. Asha needs to undergo thrombolytic therapy to dissolve the clot in order for myocardium reperfusion to occur, as the closest cardiac catheterisation lab is 2 hours away. Her vitals were taken on route to ED and the findings were:RR - 24SpO2 - 93%BP- 160/98HR - 75Temp - 36.8Pain - 7/10BGL - 9.5mmol/LHer ECG 6. how are others in the situation viewing the problem?7. what is the history of the problem? 8. who has the political power in the situation? 9. who needs to know more about the problem?  10. how effective are the current programs, strategies, and policies? 11. what are the economic inequalities in the situation? 12. what are the barriers to solving the problem?  13. what strategies may alleviate the problem?   Health Science Science Nursing Share QuestionEmailCopy link Comments (0)
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