Part 1 Part I. Poverty, Inequality, and Reform Approaches Chapter 2 Chapter 1. Introduction: Poverty Reduction in Ghana Chapter 3 Chapter 2. The Evolution of Poverty in Ghana: 1960-2000 Chapter 4 Chapter 3. The North-South Divide and the Disappearing Middle-Class: An Analysis of Spatial Inequality and Polarization in Ghana Chapter 5 Chapter 4. From SAPs to PRSPs: A Tale of Two Paradigms or Simply a Tale? Part 6 Part II. Designing, Implementing, Financing, and Monitoring the GPRS Chapter 7 Chapter 5. Public Consultations, the Role of Civil Servants, and Development Partners in Ghana's Poverty Reduction Strategy Chapter 8 Chapter 6. Linking Poverty Reduction Strategies to the Budget Chapter 9 Chapter 7. Towards an Architecture for the Delivery of International Development Assistance Chapter 10 Chapter 8. Monitoring Poverty Reduction Strategies Part 11 Part III. Special Topics in Poverty Reduction Chapter 12 Chapter 9. Decentralization, Poverty Reduction, and the Ghana Poverty Reduction Strategy Chapter 13 Chapter 10. Tackling Child Poverty in Ghana Chapter 14 Chapter 11. Employment Generation for Poverty Alleviation Chapter 15 Chapter 12. Informal Sector Activities and Urban Poverty in Ghana: Patterns and Poverty Policy Options Chapter 16 Chapter 13. Achieving Gender Equity in Ghana: How Useful is the Ghana Poverty Reduction Strategy? Chapter 17 Chapter 14. Environmental Sustainability and Poverty Reduction in Ghana Part 18 Part IV. Lessons and What Next Chapter 19 Chapter 15. Conclusions and Policy Lessons: The Next Generation of Poverty Reduction Strategies
Companies can no longer perceive themselves as stand-alone entities in the business environment. As a result of major trends such as Globalization, Outsourcing and Off-shoring, companies have more and more begun to perceive themselves as part of a chain (or network) of companies. With the increased length of chains and the increased interdependencies between organizations, coordination between such entities has become increasingly important. Due to the fact that Supply Chain (SC) decision making is distributed over various players, one of the key managerial challenges in any SC consisting of autonomous organizations is to align decisions. Typically, each organization will take decisions to optimize its own performance. But what is best for an individual organization is not always best for the SC, so that un-aligned decision making usually leaves the SC in a state of sub-optimization. Contract mechanisms might be useful to tackle such challenges. Ideally, contract mechanisms ensure that the SC is optimized as if it were a single unit (coordination) and is designed such that all players benefit from working together through the coordinating mechanism (win-win). A SC is said to be coordinated (or optimized) if it achieves the same profit as it would in a centralized situation (or full partnership). Furthermore, win-win is said to be achieved if all the players in the SC make greater profits when compared to the decentralized decision-making situation. The effectiveness of contract mechanisms lies in their design; the decision-making authorities remain unchanged, but the incentives of the various SC entities are aligned in such a way that optimizing oneâs own situation âautomaticallyâ optimizes the SC. This dissertation aims to devise contract mechanisms in various SC settings. As such it contributes to the understanding of where and how such mechanisms can coordinate operational and marketing decisions across autonomous organizations and lead to win-win. The focus is on a range of operational and marketing decisions like pricing and replenishment, promotions, service level and assortments (number of products in the product line). The methodology used in the dissertation is modeling in combination with mathematical optimization, i.e., the tools and methodology of operations research / management science are applied. The typical setting is as follows. In a two player SC with a Supplier and a Buyer, the Supplier sells the product at a wholesale price to the Buyer. The Buyer then fixes the final selling price and sells it to the end-consumer. In a traditional decentralized situation, the Supplier charges a higher wholesale price and the Buyer charges a higher retail price and orders a lower quantity than what is optimal for the entire SC. In this setting contracts like revenue-sharing and quantity discounts are designed and analyzed which can induce the Buyer to fix the final selling price and order quantity at the SC optimal level. In essence, the contract mechanisms coordinate both pricing and replenishment decisions and provide win-win opportunities. Similarly, when the end-consumer demand can be influenced by promotions, it is shown that non-optimal promotional decisions are made in a decentralized situation. A new rebate mechanism is designed to coordinate the promotional decisions and provide win-win opportunities. Furthermore, it is shown that contract mechanism can coordinate service level and product line decisions and provide win-win opportunities. The above decisions are analyzed in a wide variety of demand and supply conditions, i.e., in a variety of SC settings. For each research problem a variety of contract mechanisms have been designed and analyzed to address the issues of coordination and win-win. In all models studied, we were able to find at least one mechanism for achieving coordination and providing win-win opportunities. Furthermore, relationships between the parameters of different contract mechanisms are established wherever possible. Also, the different mechanisms have been analyzed and reviewed from an implementation perspective. In this flat (globalized) world, we believe that incentive alignment will help businesses to deliver value to their customers and maintain or enhance their competitive positioning. Therefore, in our view, this thesis will aid businesses with an important tool in aligning the incentives within their SCs.
Companies can no longer perceive themselves as stand-alone entities in the business environment. As a result of major trends such as Globalization, Outsourcing and Off-shoring, companies have more and more begun to perceive themselves as part of a chain (or network) of companies. With the increased length of chains and the increased interdependencies between organizations, coordination between such entities has become increasingly important. Due to the fact that Supply Chain (SC) decision making is distributed over various players, one of the key managerial challenges in any SC consisting of autonomous organizations is to align decisions. Typically, each organization will take decisions to optimize its own performance. But what is best for an individual organization is not always best for the SC, so that un-aligned decision making usually leaves the SC in a state of sub-optimization. Contract mechanisms might be useful to tackle such challenges. Ideally, contract mechanisms ensure that the SC is optimized as if it were a single unit (coordination) and is designed such that all players benefit from working together through the coordinating mechanism (win-win). A SC is said to be coordinated (or optimized) if it achieves the same profit as it would in a centralized situation (or full partnership). Furthermore, win-win is said to be achieved if all the players in the SC make greater profits when compared to the decentralized decision-making situation. The effectiveness of contract mechanisms lies in their design; the decision-making authorities remain unchanged, but the incentives of the various SC entities are aligned in such a way that optimizing oneâs own situation âautomaticallyâ optimizes the SC. This dissertation aims to devise contract mechanisms in various SC settings. As such it contributes to the understanding of where and how such mechanisms can coordinate operational and marketing decisions across autonomous organizations and lead to win-win. The focus is on a range of operational and marketing decisions like pricing and replenishment, promotions, service level and assortments (number of products in the product line). The typical setting is as follows. In a two player SC with a Supplier and a Buyer, the Supplier sells the product at a wholesale price to the Buyer. The Buyer then fixes the final selling price and sells it to the end-consumer. In a traditional decentralized situation, the Supplier charges a higher wholesale price and the Buyer charges a higher retail price and orders a lower quantity than what is optimal for the entire SC. In this setting contracts like revenue-sharing and quantity discounts are designed and analyzed which can induce the Buyer to fix the final selling price and order quantity at the SC optimal level. In essence, the contract mechanisms coordinate both pricing and replenishment decisions and provide win-win opportunities. Similarly, when the end-consumer demand can be influenced by promotions, it is shown that non-optimal promotional decisions are made in a decentralized situation. A new rebate mechanism is designed to coordinate the promotional decisions and provide win-win opportunities. Furthermore, it is shown that contract mechanism can coordinate service level and product line decisions and provide win-win opportunities. gned and analyzed to address the issues of coordination and win-win. In all models studied, we were able to find at least one mechanism for achieving coordination and providing win-win opportunities. Furthermore, relationships between the parameters of different contract mechanisms are established wherever possible. Also, the different mechanisms have been analyzed and reviewed from an implementation perspective. In this flat (globalized) world, we believe that incentive alignment will help businesses to deliver value to their customers and maintain or enhance their competitive positioning. Therefore, in our view, this thesis will aid businesses with an important tool in aligning the incentives within their SCs.
The Government of Ghana introduced the decentralization concept in 1988 as part of hereffort/determination to make local government administration autonomous in Ghana. Themain aim of the concept was to make the people at the grassroots part of the decision makingprocess with the view to ensuring total socio-economic transformation of the country. Untilthen, decentralization was not a new phenomenon in the politics of Ghana, however, it hassince 1988, assumed a new dimension. New structures and institutions such as the NationalDevelopment Planning Commission (NDPC), and the District Assemblies Common Fund(DACF) were established by law. These structures and institutions sought to transfer means,skills, power and competence to the districts. The DACF is believed to be the majorinnovation under the reform. The fund, which constitutes five percent of the National Income(NI), is disbursed by the central government to the districts through the Office of the CommonFund Administrator. In addition, each DA is required to generate revenues from local sourcesreferred to as Internally Generated Fund (IGF) to supplement the DACF to carry out socioeconomicdevelopment of the local areas.It is against this background that, this study was carried out to describe and explain theimplementation process of the Fiscal Decentralization Policy in the Akuapem South Districtof Ghana. The study set out to describe the assumption that inadequate bureaucratic resources,lack of political resources, poor economic and social resource and lack of inter-governmentalcommunication and enforcement agency may impede effective implementation of the fiscaldecentralization policy in the district. The Mixed method approach of social science researchand a case study approach were used in the study. Interviews and questionnaires were used tosolicit data for the study.The research found out among things that the fiscal decentralization policy is underway.However, the ability and capabilities of the DAs implement the policy is affected by variousseveral factors namely bureaucratic resource such as technical, managerial and financialresource; political resource which implies the acceptance by the bureaucrats of the policy;economic and social resource such as the social condition prevailing at the time of theimplementation; and the inter-organizational communication and enforcement agencieswhich refers to the relationship between the policy makers and the implementers. The studyconcludes that for effective implementation of fiscal decentralization in Ghana there is theneed to provide the necessary resources intended for the policy.2The study seeks to investigate the implementation of the fiscal decentralization policy in theAkuapem South District of Ghana. It aims to highlight some of the challenges confrontingthe district in the implementation of the policy and the strategies being employed to meetthese challenges.
Miguel GarcĂa GarcĂa-Revillo, Miguel JesĂșs Agudo Zamora
The recent entry into force of the 2001 UNESCO Convention on the Protection of Underwater Cultural Heritage means certainly good news for the protection of this part of the legacy of past generations. A great deal still remains to be done, however. 2001 Convention has a limited personal and material scope of application. In its absence, the international regime applicable to this kind of heritage spreads out among a number of heterogeneous instruments focused on diverse topics. One of the problems that the said diversity and heterogeneity causes is the variety of terms and definitions used by it. On the other hand, the implementation of a series of instruments so different becomes particularly complex when referring to States that have partially transferred their competences âupâ to a regional integration organization, like the European Union, and âdownâ to decentralized territorial units, like the so-called Autonomous Communities. To this respect, the case of Spain provides with a good example of such difficulties.
Peru is experiencing a deep political and fiscal decentralization process, especially since 2002. The newly created regional governments now share power and resources with the existing municipal governments as well as with the national or central government. The national government has transferred important responsibilities and fiscal resources to regional governments and also has reinforced local governmentsĂąâŹâą budgets. Both levels of subnacional governments have doubled their budget revenues in only five years. However, they are mostly financed by national government transfers instead of own collected taxes. This study analyzes in detail the functions as well as the fiscal resources of subnational governments in Peru. Based on this analysis, a set of proposals to increase direct income sources for both levels of government are discussed.
Exchange of attribute certificates is a means to establish mutual trust between strangers wishing to share resources or conduct business transactions. Automated trust negotiation (ATN) is a promising approach to regulating the exchange of sensitive information during this process. It has been a fundamental but challenging problem to preserve the privacy of the two negotiation parties during the period of ATN. We present the enhanced hidden credentials and improved concurrent zero-knowledge proof protocol. Based on the above technologies, we propose an ATN for e-business applications, named CASTLE. CASTLE can not only enable the oblivious and selective usage of an attribute or a certificate, but also be resistible for many attacks, especially conspiracy attack. We illustrate the usage of CASTLE through a typical example.
The fiscal and tax system reform in China has roughly undergone four stages which are both independent and interrelated with each other. One is from reform which concentrates on paving way for whole reform and takes the decentralization of power and transfer of profits as fundamental tone to fiscal and tax reform in 1994 which intends to take road to systematic innovation and establish a new fiscal and tax system and its operating mechanism. The second is from one-way policy of governmentâs revenue and expenditure and tax revenue within system to interaction of these two aspects both within and outside system. The third is from tax reform which standardizes governmentâs behavior of revenue and expenditure and its mechanism, and management system reform of financial expenditure to establishment of whole fiscal and tax reform and development goal. The last is from building fundamental frame of public finance to further improving public financial structure and system.
Maimonides, Averroes, and Samuel Ibn Tibbon on a Skandalon of Medieval Science Carlos Fraenkel (bio) Joel Kraemer has recently made an interesting contribution to the ongoing debate about Maimonidesâ stance in Guide 2:24 on what has been called a skandalon of medieval science:1 the incompatibility of Ptolemyâs astronomy with Aristotleâs celestial physics.2 As I understand it, the main thesis for which Prof. Kraemer argues is twofold: (1) He proposes that it is possible that the emendation suggested by Ibn Tibbon to the crucial passage in 2:24 reflects the correct Arabic original. The absence of textual evidence does not disprove this possibility, because only a fraction of the Arabic manuscripts have been examined. In addition, even if no extant Arabic manuscript contains Ibn Tibbonâs [End Page 195] version, this would not be conclusive proof that his emendation does not reflect the correct Arabic text, since it may depend on a lost branch of the Arabic manuscript tradition. (2) Considerations of content, as well as the interpretative tradition of the Guide, make it likely that Ibn Tibbonâs version is the correct one despite contrary evidence of all known Arabic manuscripts.3 In his paper Prof. Kraemer also discusses a number of alternative interpretations, including the interpretation set forth by Zev Harvey and taken up by myself. In what follows I will defend the interpretation proposed by Harvey and myself. I will first address the philological argument in support of the possibility of Ibn Tibbonâs reading. Then I will briefly discuss the value of the interpretative tradition. Finally, I will turn to the substantive issues at stake. Concerning the substantive issues, let me note from the outset that there may not actually be a fundamental disagreement between us. If I am not mistaken, Prof. Kraemer agrees that Maimonides did not consider Aristotleâs physical proof of God a demonstrative proof according to the conditions stipulated by Aristotle in the Posterior Analytics.4 Harvey and I think that this is the conclusion of Maimonidesâ argument in 2:24: because of the incompatibility of Ptolemyâs astronomy with Aristotleâs celestial physics, the crucial premise of the eternal motion of the celestial spheres cannot be taken to be necessarily true. As a consequence, the physical proof of God is not a demonstrative proof. Prof. Kraemer, on the other hand, thinks that the âgeneral proof [al-istidlÄl al-ÊżÄmm]â mentioned in the controversial passage means âdialectical proof.â5 Without Ibn Tibbonâs emendation, Maimonides would thus be denying that the heavens provide a dialectical proof of God. If this were the case Prof. Kraemer would be right: the argument of 2:24 does not support such a conclusion. Hence Ibn Tibbonâs emendation would be plausible, since for a dialectical proof the premise of the eternal motion of the celestial spheres does not need to be necessarily true. It is sufficient for it to be likely true. And there are [End Page 196] good reasons to think that according to Maimonidesâ esoteric position Aristotleâs view is more likely than the view that the world was created in time, i.e., the view for which he argues exoterically. If Maimonides had written what Ibn Tibbon and Prof. Kraemerâalbeit for different reasonsâthink he should have, I would be happy to accept Prof. Kraemerâs interpretation that in the controversial passage Maimonides is referring to a dialectical proof. Indeed, in my view this would be the only philosophically tenable interpretation. I will argue, however, that Maimonides does not deny that the heavens provide a dialectical proof of God and that this is not what Ibn Tibbon took him to be denying. According to the interpretation maintained by Harvey and myself, in the controversial passage Maimonides denies that the physical proof is a demonstrative proof, thus implicitly acknowledging that it has only dialectical status. While the conclusionâthat for Maimonides the proof is not demonstrative but dialecticalâdoes not seem to conflict with Prof. Kraemerâs view, the interpretation itself has the advantage of not depending on an unnecessary emendation of the text. 1. Ibn Tibbonâs Reading and the Interpretative Tradition I agree with Prof. Kraemer...
This book analyzes political decentralization and fiscal federalism in Canada and Germany, both traditional federal countries, and in Spain, a unitarian country engaged in the last two decades in a process of decentralization. Three key issues required for a well designed financing system are analyzed in depth, namely: tax assignment, equalization grants â i.e. redistribution of money from the wealthy regions or the national government to poorer regions, and the role of local governments in the administration of taxes.
Abstract. We construct resettably-sound resettable zero knowledge arguments for NP based on standard hardness assumption (the existence of claw-free permutations) in the plain model. This proves the simultaneous resettability conjecture posed by Barak et al. in [FOCS 2001]. Our construction, inspired by the paradigm for designing concurrent zero knowledge protocols, makes crucial use of a tool called instance-dependent resettably-sound resettable WI argument of knowledge (IDWIAOK (and a special-purpose variant), introduced recently by Deng and Lin in [Eurocrypt 2007]). Roughly speaking, for a NP statement of the form x0 âš x1, IDWIAOK is an argument for which resettable WI property holds when both x0 and x1 are YES instances, and resettably-sound argument of knowledge property holds when x0 is a NO instance. The heart of the simulator for our protocol is a new technique that allows us to embed the (non-black-box) straight-line simulation strategy in the (black-box) recursive rewinding simulation strategy. 1 The problem and our result It is well known that randomness is essential to zero knowledge proofs/arguments[17]. Moreover,
We will construct a perfectly hiding commitment in two rounds from any one-way permutation, which is a negation of this result that O(n/(log n)) rounds is the tight lower bound on the rounds complexity of perfectly hiding commitments from any one-way permutation. Based on our commitments, we will construct a computational zero-knowledge proof for any NP that achieves negligible error probability in 5 rounds of interaction, assuming only the existence of a one-way permutation.
This paper reviews the development of the Medical Financial Assistance program (MFA) in rural China, including design and implementation processes, and assesses major areas for improvement. Jointly financed by the central and local governments, MFA provides cash assistance to poor households for the purchase of medical services. Because policy design and implementation are decentralized to local governments, the schemes vary markedly across localities in terms of financing, benefit levels and payment methods. Constrained by limited financial resources, MFA benefits are granted only when recipients qualify by meeting a number of conditions. These conditions are disadvantageous to the poor, leading in general to low utilization of benefits by poor households. With increased financial input from central and local governments, the MFA schemes have been improved compared to their early design. However, additional institutionalized funding sources are needed in order to improve the policy further.
Abstract\nDecentralisation and deregulation in Swedish secondary education has put more responsibility on local school\norganization to manoeuvre in a competitive educational context. Political claims foregoing this form of quasimarket\ndevelopment in education stress enhanced opportunities for choices and stimulation of pluralistic\ninterests among students inside a more autonomous school organization. In this paper the issue of educational\nopportunities is underlined by discussing initial results from an ongoing fieldwork at a Swedish secondary\nschool. Shaped as a case study, the purpose is to investigate how students at both academic and vocational study\nprogrammes view their future opportunities in a wider socioeconomic context. More specifically the purpose is\nto examine how sociocultural conditions become decisive for evaluating possibilities and restraints of schooling.\nThe methodological approach uses multiple qualitative methods, and is inspired by theoretical perspectives that\nunderline the interconnection between individual, organization and society. Emphasis is in particular put on\nhow individual choices are shaped, mediated and channelled by institutional conditions. A theoretical\nelaboration will be tested by using Pierre Bourdieuâs concept of Habitus, as socially embodied structures, that\ncan be viewed upon as a mediating link between individual action and external power relations of the society.\nPreliminary results indicate that educational objectives set by the school in question are interpreted rather\ndifferently by the vocational and academic students. Individual perception of opportunities coincides with\nnorms and values in the local cultural environment, and results in individual strategies that overlap with local\ncollective beliefs. Both academic and vocational students pursue instrumental goals of material security and\nsocial establishment. However, the difference tends to lie in collectively tied practices of pursuing and defining\nthose aims. At the academic oriented programmes school objectives are commonly agreed upon, and are\nincorporated in the cultural environment. Conversely, mistrust and disagreement towards the goals of the\nvocational programme seems to prevail among the students. Organisational strategies are shifting in accordance\nto these different goals, respectively. From supportive and dialog-oriented conduct at the academic track, to\nconflict filled and disciplining relations at the vocational programme.\nThese early results indicate that students need to take an active part in the specific cultural setting with explicit\nnotions of consistency in order to allocate organizational resources to their favour. Moreover, this case study\ndemonstrate the increasing strong tendency that education is becoming a kind of quasi-market, which\npresupposes well-informed and ambitious students who seeks to utilise the gains in schooling. Hence, this\nilluminates the importance of further examination of how sociocultural structures condition studentsâ practical\nunderstanding of the possibilities and limitations of education.
Abstract. In this paper we consider the problem of increasing the number of possible challenge values from 2 to s in various zero-knowledge cut and choose protocols. First we discuss doing this for graph isomorphism protocol. Then we show how increasing this number improves efficiency of protocols for double discrete logarithm and e-th root of discrete logarithm which are potentially very useful tools for constructing complex cryptographic protocols. The practical improvement given by our paper is 2-4 times in terms of both time complexity and transcript size. 1
Most of the cryptographic work in privacy-preserving distributed data mining deals with semi-honest adversaries, which are assumed to follow the prescribed protocol but try to infer private information using the messages they receive during the protocol. Although the semi-honest model is reasonable in some cases, it is unrealistic to assume that adversaries will always follow the protocols exactly. In particular, malicious adversaries could deviate arbitrarily from their prescribed protocols. Secure protocols that are developed against malicious adversaries require utilisation of complex techniques. Clearly, protocols that can withstand malicious adversaries provide more security. However, there is an obvious trade-off: protocols that are secure against malicious adversaries are generally more expensive than those secure against semi-honest adversaries only. In this paper, our goal is to make an analysis of trade-offs between performance and security in privacy-preserving distributed data mining algorithms in the two models. In order to make a realistic comparison, we enhance commonly used subprotocols that are secure in the semi-honest model with zero knowledge proofs to be secure in the malicious model. We compare the performance of these protocols in both models.
faculty instructional time is a critical resource at all universities, but particularly in a major research institution like Harvard. Operating on the periphery of the Faculty of Arts and Sciences, Harvardâs division of Continuing Education is often at a disadvantage when attempting to recruit senior faculty. However, through its distance education program and its innovative use of technology, the Harvard University Extension School has been able to offer online some of the finest courses taught to the residential Harvard College students without making extraordinary demands on faculty. as a direct consequence the school is being repositioned from a peripheral role as Harvard's âevening schoolâ for local area adults to one that is available 24/7 to a growing population of enthusiastic students around the world. as the program matures, it has gained visibility and high regard by a growing number of senior faculty and by the central administration. This paper describes how Harvard Extension Schoolâs distance education model has evolved over the past ten years using the innovation life cycle methodology1, and illustrates how case studies inform the development of the program. ContinUing HigHer eDUCation review, Vol. 72, 2008 163 InnOVATInG AT THE PErIPHErY TO EXTEnd HArVArd'S COrE ORGANIZATIONAL CONTEXT Harvard University is decentralized, with authority distributed among the central administration and the 14 schools that comprise it. the president and provost are at the administrative core of the university, and if there is one unit that is its academic core, it would be the faculty of arts and sciences (FAS), which includes Harvard College, the Graduate School of Arts and Sciences (GSAS), and the division of Continuing Education (dCE), of which the extension school is a part. the degree of decentralization ensures a certain measure of independence on the part of the different schools; at the same time, for smaller units like DCe, it can mean operating on the margins of the parent institution. However, every unit of a major research university such as Harvard is mindful of its responsibility to maintain the schoolâs values in everything that it does, and a commitment to academic excellence is of primary importance. Established a century ago as an âexperiment in popular education,â the Extension School was charged with using its resources to benefit the local Boston-area community by making it possible for nontraditional students to receive a liberal education. By maintaining a policy of open enrollment and affordable tuition, the extension school has remained faithful to President Lowellâs original vision. For the most part, the Extension School has reflected the orientation of the Faculty of Arts and Sciences, offering courses primarily in the liberal arts. Comparatively recently, the school has introduced professional courses in disciplines such as computer science, management, environmental management, educational technology, and journalism in order to respond to student demand. With the advent of distance education technologies, the scope of President Lowellâs vision has been extended to include a global audience. DISTANCE EDUCATION AT HARVARD EXTENSION Although invited to do so, Harvard University did not take part in the higher-ed âdot-comâ revolution of the 1990s in a meaningful way, at least not on a broad institutional level.2 This is perhaps due to both Harvardâs decentralized structure in which individual schools decide what works for them, and the fact that faculty are highly autonomous with respect to their teaching responsibilities. By the same token, individual units have a certain freedom to experiment with technology provided that they stay within their own budgets and do no harm to the Harvard brand. 164 ContinUing HigHer eDUCation review, Vol. 72, 2008 Harvard dCEâs mission contains a commitment to âexperimenting and innovating with courses and teaching techniques that enhance the learning of non-traditional students.â Within dCE, the Harvard Extension School in particular has a tradition of embracing technology not only to improve and to complement the learning process, but also to make possible the delivery of its courses to what we today call âdistance students.â Such efforts began in the 1950s, when the Extension School offered courses via educational radio and television, and continued in the 1960s when courses were presented via kinescope to US navy personnel on board Polaris submarines. During the fall semester of 1997, the extension school carried out a controlled experiment in which a computer science courseââCommunication Protocols and Internet Architecturesââwas offered to both local and geographically distant students who were unable to attend lectures in person.3 The format of that course remains as the template for the majority of courses offered since that time: the instructorâs lectures are recorded and digitized, and relevant materials (blackboard illustrations, slides, in-class video, etc.) are integrated with streaming audio and video for on-demand access through a web browser. An example from the âCommunication Protocolsâ course is shown below; the PowerPoint slides on the right-hand side are synchronized with the audio/video presentation that appears on the left. InnOVATInG AT THE PErIPHErY TO EXTEnd HArVArd'S COrE ContinUing HigHer eDUCation review, Vol. 72, 2008 165 Building on this initial success, courses offered during the next five years (1997-2002) were primarily in computer science for the following reasons: broadband Internet bandwidth was extremely limited; our production and delivery infrastructure was crude and occasionally unreliable; and the computer science student pool, comprised mainly of experienced hardware and software engineers, could provide much of its own technical support and was accustomed to receiving feedback via email. Within a relatively short period, the distance education operation attracted attention. in 1999, a technology writer for the Boston Globe wrote favorably about the Extension Schoolâs early efforts in a feature story, âPlugging in to the Electronic Campus.â4 internally, the central administration, through the Office of the Provost, funded a study co-conducted by one of the authors that centered on two questions: How fast should the program grow? in what ways was online education transforming teaching and learning at the Extension School? Evaluation results showed clearly that faculty and students received the program well, and the growing percentage of students who were participating exclusively online proved that Extension school students were becoming comfortable with teaching and learning in virtual environments. The report helped sharpen the vision for a multi-year process of strengthening the distance program by recommending that DCe focus on pedagogy and evaluation research, as well as continue to develop student-centered tools to enhance the online learning experience.5 By 2003, the production process had become more sophisticated, as professional videographers replaced part-time student help, and the production and delivery platforms were reengineered to become stable enough to permit scaling up. Administratively, the school developed a system for online course evaluations and a method for compiling distance education student demographics through online surveys. By that point, dCE was prepared to invest heavily in infrastructure and personnel. renovated space created a professional environment for production, research and development, and allowed for staff expansion. Between 2004 and 2007, these investments paid off in the form of a rapid increase in the number of online courses offered: InnOVATInG AT THE PErIPHErY TO EXTEnd HArVArd'S COrE 166 ContinUing HigHer eDUCation review, Vol. 72, 2008 InnOVATInG AT THE PErIPHErY TO EXTEnd HArVArd'S COrE THE HARVARD COLLEGE DISTANCE EDUCATION INITIATIVE As the IT production and delivery infrastructures became stable and sophisticated, and we learned that students and faculty were satisfied, the challenge was to attract more of Harvardâs senior faculty to take advantage of our increased capacity. Over the years, various Harvard College faculty had expressed interest in teaching for the extension school, but many felt that they could not afford the time to teach an additional course in the evening. In a brainstorming conversation we came up with a simple solution to this seemingly intractable problem: If Harvard faculty did not have the time to come to us, could we go to them? in other words, could the same course that was offered during the day to Harvard College undergraduates be offered simultaneously online to extension school students? to test this idea we sought a suitable faculty member, i.e., someone who was tenured, well-respected, and interested in expanding his teaching to new audiences using digital technologies.6 in the fall, 2000, Professor H. t. Kung, the william gates Professor of Computer science and electrical Engineering, agreed to offer his CS-143 course, âComputer networks,â to an online extension school audience. as a world-renowned authority on computer networks, Prof. Kung had been experimenting with distributed 1998-99
Chunming Tang, Dingyi Pei, Xiao Feng Wang, Zhuojun Liu
A delegateable signature scheme(DSS)which was first introduced by Barak is mainly based on the non-interactive zero-knowledge proof(NIZK)for preventing the signing verifier from telling which witness(i.e.,restricted subset)is being used. However,the scheme is not significantly efficient due to the difficulty of constructing NIZK.We first show that a non-interactive witness indistinguishable(NIWI)proof sys- tem and a non-interactive witness hiding(NIWH)proof system are easier and more efficient proof models than NIZK in some cases.Furthermore,the witnesses em- ployed in these two protocols(NIWI and NIWT)cannot also be distinguished by the verifiers.Combined with theÎŁ-protocol,we then construct NIWI and NIWH proofs for any NP statement under the existence of one-way functions and show that each proof is different from those under the existence of trapdoor permutations.Finally,based on our NIWI and NIWH proofs,we construct delegateable signature schemes under the existence of one-way functions,which are more efficient than Barak's scheme under the existence of trapdoor permutations.