Using Markets and Spam to Combat Malware

We propose an economic mechanism to reduce the incidence of malware that delivers spam. Earlier research proposed attention markets as a solution for unwanted messages, and showed they could provide more net benefit than alternatives such as filtering and taxes. Because it uses a currency system, Attention Bonds faces a challenge. Zombies, botnets, and various forms of malware might steal valuable currency instead of stealing unused CPU cycles. We resolve this problem by taking advantage of the fact that the spam-bot problem has been reduced to financial fraud. As such, the large body of existing work in that realm can be brought to bear. By drawing an analogy between sending and spending, we show how a market mechanism can detect and prevent spam malware. We prove that by using a currency (i) each instance of spam increases the probability of detecting infections, and (ii) the value of eradicating infections can justify insuring users against fraud. This approach attacks spam at the source, a virtue missing from filters that attack spam at the destination. Additionally, the exchange of currency provides signals of interest that can improve the targeting of ads. ISPs benefit from data management services and consumers benefit from the higher average value of messages they receive. We explore these and other secondary effects of attention markets, and find them to offer, on the whole, attractive economic benefits for all – including consumers, advertisers, and the ISPs.

Efficient Support for Common Relations in Lightweight Formal Reasoning Systems

In work that involves mathematical rigor, there are numerous benefits to adopting a representation of models and arguments that can be supplied to a formal reasoning or verification system: reusability, automatic evaluation of examples, and verification of consistency and correctness. However, accessibility has not been a priority in the design of formal verification tools that can provide these benefits. In earlier work [Lap09a], we attempt to address this broad problem by proposing several specific design criteria organized around the notion of a natural context: the sphere of awareness a working human user maintains of the relevant constructs, arguments, experiences, and background materials necessary to accomplish the task at hand. This work expands one aspect of the earlier work by considering more extensively an essential capability for any formal reasoning system whose design is oriented around simulating the natural context: native support for a collection of mathematical relations that deal with common constructs in arithmetic and set theory. We provide a formal definition for a context of relations that can be used to both validate and assist formal reasoning activities. We provide a proof that any algorithm that implements this formal structure faithfully will necessary converge. Finally, we consider the efficiency of an implementation of this formal structure that leverages modular implementations of well-known data structures: balanced search trees and transitive closures of hypergraphs.

Analysis of institutional arrangements and common pool resources governance: the case of Lake Tana sub-basin, Ethiopia

Although Common Pool Resources (CPRs) make up a significant share of total income for rural households in Ethiopia and elsewhere in developing world, limited access to these resources and environmental degradation threaten local livelihoods. As a result, the issues of management, governance of CPRs and how to prevent their over-exploitation are of great importance for development policy. This study examines the current state and dynamics of CPRs and overall resource governance system of the Lake Tana sub-basin. This research employed the modified form of Institutional Analysis and Development (IAD) framework. The framework integrates the concept of Socio-Ecological Systems (SES) and Interactive Governance (IG) perspectives where social actors, institutions, the politico-economic context, discourses and ecological features across governance and government levels were considered. It has been observed that overexploitation, degradation and encroachment of CPRs have increased dramatically and this threatens the sustainability of Lake Tana ecosystem. The stakeholder analysis result reveals that there are multiple stakeholders with diverse interest in and power over CPRs. The analysis of institutional arrangements reveals that the existing formal rules and regulations governing access to and control over CPRs could not be implemented and were not effective to legally bind and govern CPR user’s behavior at the operational level. The study also shows that a top-down and non-participatory policy formulation, law and decision making process overlooks the local contexts (local knowledge and informal institutions). The outcomes of examining the participation of local resource users, as an alternative to a centralized, command-and-control, and hierarchical approach to resource management and governance, have called for a fundamental shift in CPR use, management and governance to facilitate the participation of stakeholders in decision making. Therefore, establishing a multi-level stakeholder governance system as an institutional structure and process is necessary to sustain stakeholder participation in decision-making regarding CPR use, management and governance.

Policy impacts on Vietnam stock markets: a case of anomalies and disequilibria 2000-2006

Vietnam launched its first-ever stock market, named as Ho Chi Minh City Securities Trading Center (HSTC) on July 20, 2000. This is one of pioneering works on HSTC, which finds empirical evidences for the following: Anomalies of the HSTC stock returns through clusters of limit-hits, limit-hit sequences; Strong herd effect toward extreme positive returns of the market portfolio;The specification of ARMA-GARCH helps capture fairly well issues such as serial correlations and fat-tailed for the stabilized period. By using further information and policy dummy variables, it is justifiable that policy decisions on technicalities of trading can have influential impacts on the move of risk level, through conditional variance behaviors of HSTC stock returns. Policies on trading and disclosure practices have had profound impacts on Vietnam Stock Market (VSM). The over-using of policy tools can harm the market and investing mentality. Price limits become increasingly irrelevant and prevent the market from self-adjusting to equilibrium. These results on VSM have not been reported before in the literature on Vietnam’s financial markets. Given the policy implications, we suggest that the Vietnamese authorities re-think the use of price limit and give more freedom to market participants.

Art markets

SCOPUS: ch.b

The Vietnam's Transition Economy and Its Fledgling Financial Markets: 1986-2003

In this paper, we analyze the context of Vietnam’s economic standings in the reform period. The first section embarks on most remarkable factors, which promote the development of financial markets are: (i) Doi Moi policies in 1986 unleash ‘productive powers’. Real GDP growth, and key economic indicators improve. The economy truly departs from the old-style command economy; (ii) FDI component is present in the economy as sine qua non; a crucial growth engine, forming part of the financial markets, planting the ‘seeds’ for its growth; and (iii) the private economy is both the result and cause of the reform. Its growth is steady. Today, it represents a powerhouse, and helps form part of the genuine financial economy. A few noteworthy points found in the next section are: (i) No evidence of financial markets existence was found before Doi Moi. The reform has generated a bulk of private-sector financial companies. New developments have roots in the 1992-amended constitution (x3.2); (ii) The need to reform the financial started with the domino collapse of credit cooperatives in early 1990s. More stress is caused by the ‘blow’ of banking deficiency in late 1990s; and (iii) Laws on SBV and credit institutions, and the launch of the stock market are bold steps. Besides, the Asian financial turmoil forces the economy to reaffirm its reform agenda. Our findings also indicate, through empirical evidences, that economic conditions have stabilized throughout the reform, thanks to the contributions of the FDI and private economic sector. Private investment flows continue to be an eminent factor that drives the economy growth.

A theory of buyer-seller networks

This paper introduces a new model of exchange: networks, rather than markets, of buyers and sellers. It begins with the empirically motivated premise that a buyer and seller must have a relationship, a "link," to exchange goods. Networks - buyers, sellers, and the pattern of links connecting them - are common exchange environments. This paper develops a methodology to study network structures and explains why agents may form networks. In a model that captures characteristics of a variety of industries, the paper shows that buyers and sellers, acting strategically in their own self-interests, can form the network structures that maximize overall welfare.

Equity trading volume and volatility: Latent information arrivals and common long-run dependencies

This article examines the behavior of equity trading volume and volatility for the individual firms composing the Standard & Poor's 100 composite index. Using multivariate spectral methods, we find that fractionally integrated processes best describe the long-run temporal dependencies in both series. Consistent with a stylized mixture-of-distributions hypothesis model in which the aggregate "news"-arrival process possesses long-memory characteristics, the long-run hyperbolic decay rates appear to be common across each volume-volatility pair.

A multivariate generalized ARCH approach to modeling risk premia in forward foreign exchange rate markets

Assuming that daily spot exchange rates follow a martingale process, we derive the implied time series process for the vector of 30-day forward rate forecast errors from using weekly data. The conditional second moment matrix of this vector is modelled as a multivariate generalized ARCH process. The estimated model is used to test the hypothesis that the risk premium is a linear function of the conditional variances and covariances as suggested by the standard asset pricing theory literature. Little supportt is found for this theory; instead lagged changes in the forward rate appear to be correlated with the 'risk premium.'. © 1990.

How common are common mental disorders? Evidence that lifetime prevalence rates are doubled by prospective versus retrospective ascertainment.

BACKGROUND: Most information about the lifetime prevalence of mental disorders comes from retrospective surveys, but how much these surveys have undercounted due to recall failure is unknown. We compared results from a prospective study with those from retrospective studies. METHOD: The representative 1972-1973 Dunedin New Zealand birth cohort (n=1037) was followed to age 32 years with 96% retention, and compared to the national New Zealand Mental Health Survey (NZMHS) and two US National Comorbidity Surveys (NCS and NCS-R). Measures were research diagnoses of anxiety, depression, alcohol dependence and cannabis dependence from ages 18 to 32 years. RESULTS: The prevalence of lifetime disorder to age 32 was approximately doubled in prospective as compared to retrospective data for all four disorder types. Moreover, across disorders, prospective measurement yielded a mean past-year-to-lifetime ratio of 38% whereas retrospective measurement yielded higher mean past-year-to-lifetime ratios of 57% (NZMHS, NCS-R) and 65% (NCS). CONCLUSIONS: Prospective longitudinal studies complement retrospective surveys by providing unique information about lifetime prevalence. The experience of at least one episode of DSM-defined disorder during a lifetime may be far more common in the population than previously thought. Research should ask what this means for etiological theory, construct validity of the DSM approach, public perception of stigma, estimates of the burden of disease and public health policy.

A novel mutation of the ACADM gene (c.145C>G) associated with the common c.985A>G mutation on the other ACADM allele causes mild MCAD deficiency: a case report.

A female patient, with normal familial history, developed at the age of 30 months an episode of diarrhoea, vomiting and lethargy which resolved spontaneously. At the age of 3 years, the patient re-iterated vomiting, was sub-febrile and hypoglycemic, fell into coma, developed seizures and sequels involving right hemi-body. Urinary excretion of hexanoylglycine and suberylglycine was low during this metabolic decompensation. A study of pre- and post-prandial blood glucose and ketones over a period of 24 hours showed a normal glycaemic cycle but a failure to form ketones after 12 hours fasting, suggesting a mitochondrial β-oxidation defect. Total blood carnitine was lowered with unesterified carnitine being half of the lowest control value. A diagnosis of mild MCAD deficiency (MCADD) was based on rates of 1-14C-octanoate and 9, 10-3H-myristate oxidation and of octanoyl-CoA dehydrogenase being reduced to 25% of control values. Other mitochondrial fatty acid oxidation proteins were functionally normal. De novo acylcarnitine synthesis in whole blood samples incubated with deuterated palmitate was also typical of MCADD. Genetic studies showed that the patient was compound heterozygous with a sequence variation in both of the two ACADM alleles; one had the common c.985A>G mutation and the other had a novel c.145C>G mutation. This is the first report for the ACADM gene c.145C>G mutation: it is located in exon 3 and causes a replacement of glutamine to glutamate at position 24 of the mature protein (Q24E). Associated with heterozygosity for c.985A>G mutation, this mutation is responsible for a mild MCADD phenotype along with a clinical story corroborating the emerging literature view that patients with genotypes representing mild MCADD (high residual enzyme activity and low urinary levels of glycine conjugates), similar to some of the mild MCADDs detected by MS/MS newborn screening, may be at risk for disease presentation.

Innovation in business groups

Using novel data on European firms, this paper investigates the relationship between business groups and innovation. Controlling for various firm characteristics, we find that group affiliates are more innovative than standalones. We examine several hypotheses to explain this finding, focusing on group internal capital markets and knowledge spillovers. We find that group affiliation is particularly important for innovation in industries that rely more on external funding and in groups with more diversified capital sources, consistent with the internal capital markets hypothesis. Our results suggest that knowledge spillovers are not the main driver of innovation in business groups because firms affiliated with the same group do not have a common research focus and are unlikely to cite each other's patents. © 2010 INFORMS.

Common genetic variation and the control of HIV-1 in humans.

To extend the understanding of host genetic determinants of HIV-1 control, we performed a genome-wide association study in a cohort of 2,554 infected Caucasian subjects. The study was powered to detect common genetic variants explaining down to 1.3% of the variability in viral load at set point. We provide overwhelming confirmation of three associations previously reported in a genome-wide study and show further independent effects of both common and rare variants in the Major Histocompatibility Complex region (MHC). We also examined the polymorphisms reported in previous candidate gene studies and fail to support a role for any variant outside of the MHC or the chemokine receptor cluster on chromosome 3. In addition, we evaluated functional variants, copy-number polymorphisms, epistatic interactions, and biological pathways. This study thus represents a comprehensive assessment of common human genetic variation in HIV-1 control in Caucasians.

Detection methods for common problems in solar home systems

Gemstone Team SHINE (Students Helping to Implement Natural Energy)