30 research outputs found

    The Innovation Premium

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    Firms that engage in innovative product development, as measured by the fraction of their investment that goes to Research and Development (R&D) activities, earn higher risk-adjusted equity returns. A portfolio that goes long the most innovative and shorts the least innovative firms earns a risk-adjusted return in excess of 7% per annum. R&D-intensive firms also tend to charge higher price markups. Combining insights from industrial organization with a production-based asset pricing framework, I propose a model in which heterogeneous firms produce vertically differentiated goods and market them to heterogeneous consumers. Firms are subject to aggregate demand and supply shocks, which are both priced by investors, and thus the return premium of innovative firms is explained by their differential exposures to these shocks. In addition to explaining this return spread, the model makes predictions on firm investments, future profit markups, and firm size that are consistent with the data

    Essays In Macro-Finance And Asset Pricing

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    This dissertation consists of three parts. The first documents that more innovative firms earn higher risk-adjusted equity returns and proposes a model to explain this. Chapter two answers the question of why firms would choose to issue callable bonds with options that are always out of the money by proposing a refinancing-risk explanation. Lastly, chapter three uses the firm-level evidence on investment cyclicality to help resolve the aggregate puzzle of whether R\&D should be procyclical or countercylical

    Why Do Firms Issue Callable Bonds?

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    Corporations in the US have significantly increased their usage of callable bonds in the past 10-15 years. Whereas callable debt was issued in the past for interest rate hedging motives, the vast majority of callable bonds issued today have call options that will enver be in the money . This feature implies that previous explanations for the issuance of callable debt no longer rationalize the current pattern. We present evidence on the types of firms issuing these bonds and their usage of the proceeds, which motivates a new theory for why firms desire these eternally out of the money call options. This theory captures the motives of firms in matching the maturities of investment and financing and endogenously generates firm-specific refinancing risk. We then embed this theory into a production-based model and show that callable bonds can expand access to capital markets and increase investment

    Deploying a Sensor Network in an Extreme Environment

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    A wireless sensor network has been designed and deployed to gather data from nodes on and inside glaciers. This paper describes the solutions to power management, radio communications, management and discusses the performance of the final system. 18 months of data have now been received, which provide an insight not only into the glacier’s behaviour but on the design decisions. The system uses custom PIC-based sensor nodes and an ARM-based base station which controls weather and differential GPS. Different versions have been installed in Norway from 2003-5 and this paper describes the lessons learnt from coping with the extreme conditions found in glaciers

    تحليل العوامل للتكاليف الإنتاجية والتنبؤ بإنتاجية أهم المحاصيل الحقلية في مصر

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    The research problem is to answer the question: What are the main components of the production costs items for the most important field crops (wheat, rice, summer maize) in Egyptian agriculture? Are there changes in the area of these crops? In achieving its goals, the research relied on a descriptive and quantitative analysis method, relying on tabular and graphical presentation, percentages, engineering and mathematical averages, and growth rates, in addition to Runs Test, Factor Analysis using the major or fundamental component analysis method (PCA) for the most important Items of costs (workers’ wages, seeds, fertilizers, mechanization, other) of the field crops under study question. The research reached a number of results, including: •Wheat crop: From the test runs of the wheat crop area in the four geographical regions during the study period, it is noted that the number of courses during the study period reached two courses for the sea side, 4 courses in Middle Egypt, 6 courses for the tribal face and the total of the republic, and it is expected that the value of acre productivity in In 2024 to 20.9 million erdeb for Lower Egypt and Middle Egypt, 16.7 million erdeb for Upper Egypt, 20.7 million erdeb for the total Egypt. •Rice crop: Results of the test runs for the rice crop area in the four geographical regions during the study period. It is noted that the number of courses during the study period reached 8 courses for the sea side and the total of the republic, 11 courses in Middle Egypt, 7 courses for the tribal face, and it is expected that the value of acre productivity In the year 2024 to 3.4 million tons for Lower Egypt and the total Egypt, 3.5 million tons for Middle Egypt, 4.3 million tons for Upper Egypt. •Maize crop: Runs test for the rice crop area in the four geographical regions during the study period, from which it is noted that the number of courses during the study period reached 14 courses for Lower Egypt, 6 courses in Middle Egypt, 4 courses for Upper Egypt and the total of the Republic, and it is expected that the value of productivity will reach to 25.8 million erdeb in 2024 for Lower Egypt, 22.3 million erdeb for Middle Egypt, 17.8 million erdeb for Upper Egypt, 23.6 million erdeb for the total Egypt. تتمثل مشكلة البحث في الإجابة على التساؤلات التالية: ما هي المكونات الأساسية لبنود التكاليف الإنتاجية لأهم المحاصيل الحقلية (القمح، الأرز، الذرة الشامية الصيفية) في الزراعة المصرية؟ وهل هناك تغيرات فى المساحة لهذه المحاصيل؟ واعتمد البحث في تحقيق أهدافه على أسلوب التحليل الوصفي والكمي، معتمداً على العرض الجدولي والبياني، والنسب المئوية، والمتوسطات الحسابية والهندسية، ومعدلات النمو، بالإضافة إلى اختبار الأشواطRuns Test، تحليل العوامل Factor Analysis باستخدام طريقة تحليل المكون الرئيسي أو الأساسي Principle Component Analysis “PCA” لأهم بنود التكاليف (أجور العمال، التقاوي، الأسمدة، الميكنة، أخرى) للمحاصيل موضع البحث، وتوصل البحث إلى عدد من النتائج منها: • محصول القمح: من اختبار الأشواط لمساحة محصول القمح بالمناطق الجغرافية الثلاثة بالإضافة إلى إجمالي الجمهورية خلال فترة الدراسة، يُلاحظ أن عدد الدورات خلال فترة الدراسة بلغ دورتين للوجه البحري، 4 دورات في مصر الوسطى، 6 دورات للوجه القبلي وإجمالي الجمهورية، ومن المتوقع أن تصل قيمة الإنتاجية الفدانية في عام 2024 إلى 20.9 مليون أردب للوجه البحري ومصر الوسطى، 16.7 مليون أردب للوجه القبلي، 20.7 مليون أردب لإجمالي الجمهورية. • محصول الأرز: نتائج اختبار الأشواط لمساحة محصول الأرز بالمناطق الجغرافية الأربعة خلال فترة الدراسة، يُلاحظ أن عدد الدورات خلال فترة الدراسة بلغ 8دورات للوجه البحري وإجمالي الجمهورية، 11 دورات في مصر الوسطى، 7 دورات للوجه القبلي، ومن المتوقع أن تصل قيمة الإنتاجية الفدانية في عام 2024 إلى 3.4 مليون طن للوجه البحريوإجمالي الجمهورية، 3.5 مليون طن لمصر الوسطى، 4.3 مليون طن للوجه القبلي. • محصول الذرة الشامية: اختبار الأشواط لمساحة محصول الأرز بالمناطق الجغرافية الأربعة خلال فترة الدراسة، ومنها يُلاحظ أن عدد الدورات خلال فترة الدراسة بلغ 14 دورة للوجه البحري، 6 دورات في مصر الوسطى، 4 دورات للوجه القبلي وإجمالي الجمهورية، ومن المتوقع أن تصل قيمة الإنتاجية الفدانية في عام 2024 إلى 25.8 مليون أردب للوجه البحري، 22.3 مليون أردب لمصر الوسطى، 17.8 مليون أردب للوجه القبلي، 23.6 مليون أردب لإجمالي الجمهورية. الكلمات الدليلية: تحليل العوامل Factor Analysis، اختبار الأشواط Runs Test، التنبؤ، الإنتاجية

    Structure Learning for Activity Recognition in Robot Assisted Intelligent Environments

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    Abstract-This paper presents a novel structure learning algorithm for the creation of distributed Bayesian networks over static and mobile Vision Sensor Network (VSN) nodes. These compose an assistive, intelligent environment for activity recognition. We provide results demonstrating a higher level of accuracy in the recognition of fine motor tasks when the environment is augmented with a mobile robot and show the ability of our learning algorithm to reduce VSN communication compared to a naïve, greedy structure learning technique. I. INTRODUCTION UE to recent advances in medical care and the adoption of increasingly healthy lifestyles, we are witnessing a demographic shift towards an increasingly aged population Where environments are to contain multiple ambient sensors, installation may be performed by a visiting carer or those living within the domicile. Consequently, it is unreasonable to expect these to be located at optimal locations for the determination of individual activities. Furthermore, since each dwelling is unique, their relative positioning can not be assumed prior to installation thus there is a strong requirement for such networks to be self configuring. To this end, we provide a structure learning algorithm for Bayesian networks which is considerate of both inference and communication cost within ambient Vision Sensor Networks (VSNs). Using Pearl's message propagation algorithm, activity inference can be implemented in a distributed manner over the VSNs, without the requirement for a centralized data repository. Where assistive robots are present, our algorithm can seamlessly incorporate such data to augment recognition accuracy. We demonstrate the efficacy of this algorithm in a home healthcare scenario for fine motor tasks occurring at several locations within the environment. II. RELATED RESEARCH For detecting Activities of Daily Living (ADLs), omnidirectional cameras [6] have previously been employed to capture behavioral patterns in a household environment. For example, a system operating at multiple resolutions has been defined, with a wide angle camera directing the pan, tilt and zoom of other camera

    A review of the design and clinical evaluation of the ShefStim array-based functional electrical stimulation system

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    Functional electrical stimulation has been shown to be a safe and effective means of correcting foot 12 drop of central neurological origin. Current surface-based devices typically consist of a single channel stimulator, 13 a sensor for determining gait phase and a cuff, within which is housed the anode and cathode. The cuff-mounted 14 electrode design reduces the likelihood of large errors in electrode placement, but the user is still fully responsible 15 for selecting the correct stimulation level each time the system is donned. Researchers have investigated different 16 approaches to automating aspects of setup and/or use, including recent promising work based on iterative learning 17 techniques. This paper reports on the design and clinical evaluation of an electrode array-based FES system for 18 the correction of drop foot, ShefStim. The paper reviews the design process from proof of concept lab-based study, 19 through modelling of the array geometry and interface layer to array search algorithm development. Finally, the 20 paper summarises two clinical studies involving patients with drop foot. The results suggest that the ShefStim 21 system with automated setup produces results which are comparable with clinician setup of conventional systems. 22 Further, the final study demonstrated that patients can use the system without clinical supervision. When used 23 unsupervised, setup time was 14 minutes (9 minutes for automated search plus 5 minutes for donning the 24 equipment), although this figure could be reduced significantly with relatively minor changes to the design

    GWMAC- A TDMA Based MAC Protocol for a Glacial Sensor Network

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    Wireless sensor networks demand the need to design practical and robust communication protocols to meet the application specifications. Our research focuses on designing and implementing an environmental sensor network to be used for sub-glacial study. The glacier is a very hostile environment presenting severe challenges and complications in the smooth functioning of such a network. In light of these challenges, we present a low power sensor node design and an energy-efficient medium access control protocol called GWMAC developed for a network deployed in a glacier in Norway. The general architecture of GWMAC is based on scheduling and time division multiple accesses (TDMA). We argue that for a highly dynamic network such as ours, GWMAC is more desirable over more widespread protocols such as S-MAC and LMAC. In doing so, we perform extensive series of simulations to empirically evaluate our claim. Our results illustrate that on average GWMAC can increase the network life time by at least 63%. This also has a significant effect on the amount of data that can be collected over network life time

    Correlation between preoperative calcium and parathormone levels with parathyroid gland volume

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    Objective. Hyperparathyroidism is a prevalent disease with parathyroid adenomas being the most common cause. Surgical excision remains the standard treatment for parathyroid adenoma. Successful preoperative localization of the parathyroid adenoma could facilitate the decision regarding the extent of surgical exploration. The aim of the current study was to assess the correlation between the preoperative values of parathyroid hormone and ionized calcium with the adenoma weight and volume in patient with primary hyperparathyroidism caused by single-gland adenoma

    Correlation between the size of pheochromocytoma and the level of metanephrines

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    Objective. Pheochromocytomas (PHEO) and paraganglioma (PGLs) are rare neuroendocrine catecholamine-producing tumors that arise from the chromaffin cells of either the adrenal medulla or extra-adrenal paraganglionic tissues. Despite the recent advances in imaging technologies, biochemical evidence of excessive catecholamine production by the tumor is considered the most important test for the diagnosis of these tumors. The aim of the present study is to investigate the role of the catecholamine metabolites (normetanephrine and metanephrine) levels in the diagnosis of PHEO/PGLs and to evaluate if their levels correlate with the size of these tumors
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