Secure communication in IP-based wireless sensor network via a trusted gateway

As the IP-integration of wireless sensor networks enables end-to-end interactions, solutions to appropriately secure these interactions with hosts on the Internet are necessary. At the same time, burdening wireless sensors with heavy security protocols should be avoided. While Datagram TLS (DTLS) strikes a good balance between these requirements, it entails a high cost for setting up communication sessions. Furthermore, not all types of communication have the same security requirements: e.g. some interactions might only require authorization and do not need confidentiality. In this paper we propose and evaluate an approach that relies on a trusted gateway to mitigate the high cost of the DTLS handshake in the WSN and to provide the flexibility necessary to support a variety of security requirements. The evaluation shows that our approach leads to considerable energy savings and latency reduction when compared to a standard DTLS use case, while requiring no changes to the end hosts themselves

Intrinsic attenuation in multi-mode fiber interconnects

A Wilson basis is an ingenious modification of a Gabor frame, with basis functions that have a notionally compact support in phase space. We shall give a short description of an algorithm for the construction of a Wilson basis. Through spatial scaling of the Wilson basis relative to a higher-order LP-mode, the basis may appear to vary from effectively local to effectively global. For mode-matching purposes local is advantageous. However, the field expansion requires fewer coefficients in the more global basis

Dynamic Causal Forests, with an Application to Payroll Tax Incidence in Norway

This paper develops a machine-learning method that allows researchers to estimate heterogeneous treatment effects with panel data in a setting with many covariates. Our method, which we name the dynamic causal forest (DCF) method, extends the causal-forest method of Wager and Athey (2018) by allowing for the estimation of dynamic treatment effects in a difference-in-difference setting. Regular causal forests require conditional independence to consistently estimate heterogeneous treatment effects. In contrast, DCFs provide a consistent estimate for heterogeneous treatment effects under the weaker assumption of parallel trends. DCFs can be used to create event-study plots which aid in the inspection of pre-trends and treatment effect dynamics. We provide an empirical application, where DCFs are applied to estimate the incidence of payroll tax on wages paid to employees. We consider treatment effect heterogeneity associated with personal- and firm-level variables. We find that on average the incidence of the tax is shifted onto workers through incidental payments, rather than contracted wages. Heterogeneity is mainly explained by firm-and workforce-level variables. Firms with a large and heterogeneous workforce are most effective in passing on the incidence of the tax to workers

International study on the long-term efficiency of stormwater infiltration by permeable pavements

Although permeable pavements have been used all over the world in recent years to infiltrate and treat stormwater, only limited research has been undertaken to investigate and compare the long-term performance of these sustainable urban drainage system devices. This paper presents the results of an extensive international review of research on the reduction of infiltration capacity of permeable pavements over time. The results of these studies, coupled with specific knowledge of the key environmental factors on the individual research locations and infiltration testing methods used, enables the maintenance of these SUDS to be strategically planned in order to meet specific European and international infiltration capacity guidelines

Welfare Effect of Closing Loopholes in the Dividend-Withholding Tax: The Case of Cum-cum and Cum-ex Transactions

We study the effect of reforms that close loopholes in the enforcement of the dividend withholding tax (DWT). We focus on a Danish reform enacted in 2016, and compare Denmark to its Nordic neighbors. Our main outcome of interest is the quantity of stocks on loan. Before the reform all Nordic countries have a strong spike in stocks on loan centered around the ex-dividend day. The magnitude is large: on average excess stocks on loan peak at around 4 percent of the public float. The spike in lending is consistent with the most popular DWT arbitrage schemes. After the reform the spikes in Denmark disappear, but they continue in the other Nordics. We interpret this as evidence that the reform was successful at eliminating DWT arbitrage. We consider the welfare effects of the reform. Using synthetic difference-in-difference we find that stricter DWT enforcement resulted in a 130 percent (approx. 1.3 bln USD annually) increase in DWT revenue in Denmark. We detect no changes in foreign portfolio investment or dividend policy. We also consider DWT arbitrage among 15 European countries between 2010-2019. We find evidence of DWT arbitrage in all countries that levy DWT, though there is strong heterogeneity across countries. Importantly, similar to Denmark, Germany’s 2016 reform has eliminated the spikes in lending completely. We validate our identification strategy by showing that we find no evidence of DWT arbitrage in the UK, which does not levy a DWT

Optimal Taxation with Multiple Incomes and Types

We analyze the optimal nonlinear income tax schedule when taxpayers earn multiple in comes and differ along many unobserved dimensions. We derive the necessary conditions for the government’s optimum using both a tax perturbation and a mechanism design approach, and show that both methods produce the same results. Our main contribution is to propose a numerical method to find the optimal tax schedule. Applied to the optimal taxation of couples, we find that optimal isotax curves are very close to linear and parallel. The slope of isotax curves is strongly affected by the relative tax-elasticity of male and female income. We make several additional contributions, including a test for Pareto efficiency and a condition on primitives that ensures the government’s necessary conditions are sufficient and the solution to the problem is unique

Climatescan.nl: the development of a web-based map application to encourage knowledge-sharing of climate-proofing and urban resilient projects

Over recent years, there has been an explosion in the number and diversity of projects undertaken to address urban resilience and climate proofing. Sharing the knowledge gained from these projects demands increasingly innovative and accessible methods. This paper details the outcomes of one such initiative: an interactive web-based map application that provides an entry point to gain detailed information of various ‘blue-green’ projects. The climatescan.nl has proven to be a successful tool in several international workshops, not only for field-based practitioners but also for those involved in teaching and research. Further upscaling is needed however if the full potential of such an application is to be achieved

Paraganglioma of the cauda equina region

BACKGROUND CONTEXT: Cauda equina paragangliomas (CEPs) are rare neuroendocrine tumors. The difficulty in differential diagnosis with other tumors of this region may be misleading for surgical planning and prognostic expectations. PURPOSE: To report on a rare case of CEP and review the most current information regarding the diagnosis, treatment options, and outcomes. STUDY DESIGN: Case report and literature review. PATIENT SAMPLE: One patient affected by CEP. METHODS: We report on a 33-year-old woman with a 2-month history of worsening low back pain, aggravated by sitting, bending, and coughing. Neurological examination revealed normal power and muscular tone, no sensory or sphincter abnormality, and normal reflex. Magnetic resonance imaging of the lumbar spine demonstrated an intradural extramedullary lesion at L3, with homogeneous contrast enhancement and hypointense punctate foci. The patient underwent an L3 laminectomy and tumor removal. Relevant articles covering CEPs from 1970 to the present were reviewed. RESULTS: The histopathological examinations described paraganglioma features. The postoperative coursewas uneventful, and all the symptoms resolved, with no tumor recurrence after 3 years’ follow-up. CONCLUSIONS: Cauda equina paragangliomas are rare, benign, and slow-growing tumors. Except for its secreting tumor characteristics, preoperative CEP diagnosis is very difficult.Magnetic resonance imaging is important andmay suggest specific radiological features for these tumors; however, these are only relative, and it is rare that diagnosis ismade before surgery.Diagnosis is established by histological examination and electron microscopy, and immunohistochemical techniques must be used to achieve a correct diagnosis. Cauda equina paragangliomas arewell-encapsulated tumors that may be cured by surgery alone, whereas radiotherapy is reserved for incompletely resected tumors. Overall, prolonged postoperative observation is mandatory because of the slow tumor evolution and the possibility of tumor relapse even up to 30 years after surgery

Triple Therapy Protocol for Primary and Secondary Auricular Keloids:A Prospective Outcome Evaluation

BACKGROUND:Ear keloid lesions present a significant challenge to the aesthetic surgeon. Keloids are known to recur and can cause severe cosmetic, functional, and psychological impairments. Several adjuvants to surgical removal have been promoted, with varying recurrence rates. OBJECTIVE: To evaluate the effectiveness of triple therapy to treat secondary (and large primary) auricular keloids. MATERIALS AND METHODS: Patients with secondary or large primary auricular keloids undergoing triple therapy were prospectively studied. Keloids were excised intramarginally under magnification and repeated triamcinolone acetonide 40 mg/mL injections were administered, followed by the application of a custom-made acrylate pressure device. Recurrent keloid formation and adverse events were monitored during a minimum of 6 months of follow-up. RESULTS: Sixteen auricular keloid lesions (3 large primary and 13 secondary) were subjected to the proposed technique with a mean follow-up of 28 months. All cases that adhered to the protocol were free of keloid after triple therapy. Side effects were limited to 1 case of lobular atrophy and slight hypopigmentation. All patients were satisfied with the results. CONCLUSION: The triple therapy protocol is highly effective in primary and secondary auricular keloid as long as patients remain compliant.</p