Cross-Sectional Variation of Intraday Liquidity, Cross-Impact, and Their Effect on Portfolio Execution

Over the past decade, there has been a significant rise in assets managed under passive and systematic strategies. Such strategies hold and trade portfolios in a coordinated manner, often concentrating trading around the end of the trading session. Simultaneously, there has been a rise in activity from market participants that act as liquidity providers, themselves trading along portfolio directions. In “Cross-Sectional Variation of Intraday Liquidity, cross-impact, and Their Effect on Portfolio Execution,” Min, Maglaras, and Moallemi investigate the implications of these two observations, specifically exploring how the phenomenon of portfolio liquidity provision leads to cross-security impact and influences the optimal execution schedules of risk-neutral traders that seek to minimize their expected execution costs. They show that the optimized schedules deviate from the naïve approach that trades each security separately and instead, couple the trading intensity across stocks so as to benefit from the liquidity provided along attractive portfolio trading directions. Empirical analysis demonstrates that coupled optimized schedules could lower costs by as much as 15% relative to the naïve approach.

CrowdMed-II: a blockchain-based framework for efficient consent management in health data sharing

The healthcare industry faces serious problems with health data. Firstly, health data is fragmented and its quality needs to be improved. Data fragmentation means that it is difficult to integrate the patient data stored by multiple health service providers. The quality of these heterogeneous data also needs to be improved for better utilization. Secondly, data sharing among patients, healthcare service providers and medical researchers is inadequate. Thirdly, while sharing health data, patients’ right to privacy must be protected, and patients should have authority over who can access their data. In traditional health data sharing system, because of centralized management, data can easily be stolen, manipulated. These systems also ignore patient’s authority and privacy. Researchers have proposed some blockchain-based health data sharing solutions where blockchain is used for consensus management. Blockchain enables multiple parties who do not fully trust each other to exchange their data. However, the practice of smart contracts supporting these solutions has not been studied in detail. We propose CrowdMed-II, a health data management framework based on blockchain, which could address the above-mentioned problems of health data. We study the design of major smart contracts in our framework and propose two smart contract structures. We also introduce a novel search contract for searching patients in the framework. We evaluate their efficiency based on the execution costs on Ethereum. Our design improves on those previously proposed, lowering the computational costs of the framework. This allows the framework to operate at scale and is more feasible for widespread adoption.

Towards a Smart Privacy-Preserving Incentive Mechanism for Vehicular Crowd Sensing

Vehicular crowd sensing is a promising approach to address the problem of traffic data collection by leveraging the power of vehicles. In various applications of vehicular crowd sensing, there exist two burning issues. First, privacy can be easily compromised when a vehicle is performing a crowd sensing task. Second, vehicles have no incentive to submit high-quality data due to the lack of fairness, which means that everyone gets the same paid, regardless of the quality of the submitted data. To address these issues, we propose a smart privacy-preserving incentive mechanism (SPPIM) for vehicular crowd sensing. Specifically, we first propose a new SPPIM model for the scenario of vehicular crowd sensing via smart contract on the blockchain. Then, we design a privacy-preserving incentive mechanism based on budget-limited reverse auction. Anonymous authentication based on zero-knowledge proof is utilized to ensure the privacy preservation of vehicles. To ensure fairness, the reward payments of winning vehicles are determined by not only the bids of vehicles but also their reputation and the data quality. Then, any rewarded vehicle can get the fair payment; on the contrary, malicious vehicles or task initiators will be punished. Finally, SPPIM is implemented by using smart contracts written via Solidity on a local Ethereum blockchain network. Both security analysis and experimental results show that the proposed SPPIM achieves privacy preservation and fair incentives at acceptable execution costs.

Applied study on the rotational molding and processing technology of rotational molds

Computer-aided manufacturing involves a set of computerized activities related to the preparation, launch and follow-up of manufacturing. Computer-aided manufacturing is a tool that allows the use of 3D models based on computer-aided design. This paper addresses the process of rotational formation, with an effective focus on the technology of processing a rotational mold using CAM simulation as a research method. In this sense, the right choice of CNC and cutting tools is essential. The use of numerically controlled machine tools and high-performance cutting tools reduces the number of operations. The manufacturing route realized is specific to the parts machining on numerical control machine, with multiple possibilities such as the execution on a single machine of all the necessary operations to create the mold. PowerMILL gives the user the flexibility to generate thisheir NC programs and ensures the use of the most efficient processing method without having to wait for the complete calculation. A number of different strategies, from the wide range that PowerMILL has, are compared using a high tolerance so that they can be calculated quickly. In this study, the strengths of the CNC are highlighted based on experimental research, features that make this machine a very productive one, saving time, energy and, implicitly, low execution costs.

Proposta para Implantação de um Setor de Planejamento de Obras: um estudo de caso na companhia de saneamento de Sergipe ## Proposal for Implementation of a Construction Planning Sector: a case study in the Sergipe purification company

ResumoO objetivo geral dessa pesquisa é propor a padronização dos procedimentos de orçamentação e indicar um setor de planejamento subordinado a Gerência de Orçamento. Como objetivos específicos: avaliar as definições e atribuições do atual setor de orçamento, identificar elementos que podem compor os manuais de orçamentação e propor meios para implantação da coordenação de planejamento subordinados a Gerência de Orçamento e sua associação com os setores de projeto e execução de obras. Foi realizada uma pesquisa qualitativa, de natureza participativa. O resultado identificou que a padronização dos procedimentos de orçamentação deve garantir a agilidade e confiabilidade dos produtos fornecidos pela Gerência de Orçamento, além de promover uma redução das perdas, sejam elas intelectuais ou financeiras. Quanto à implantação do setor de planejamento, os resultados podem reduzir os custos operacionais e de execução dos empreendimentos na empresa são altos, além do tempo necessário para conclusão destes. AbstractIn this research the main objective is propose the standardization of budgeting procedures and indicates a planning sector subordinated to Budget Management. As specific objectives: evaluate the definitions and attributions of the current budget sector, identify elements that can compose the budget manuals and propose methods for implementation of the planning coordination subordinated to Budget Management and its association with the project and execution sectors. A qualitative, participatory research was conducted. The result identified that the standardization of budgeting procedures should ensure the agility and reliability of the products provided by the Budget Management, as well as promotes a reduction of losses, whether intellectual or financial. Regarding the implementation of the planning sector, the results can reduce the operational and execution costs of the projects in the company are high, besides the time required to complete them.

ENGINEERING AND GEODESIC SURVEYS AT ESTABLISHING DEPOSITS

The article presents a general approach to the implementation of engineering and geodetic surveys when arranging a sand pit in the conditions of the spread of permafrost soils. It is believed that the solution to the problems arising in the extraction of minerals in the Yamal-Nenets Autonomous district is possible using the described methodology. The considered method using modern geodetic instruments (GNS-receivers, TOPCON GTS-239N total station, “Credo-dialogue” software complexes) will allow obtaining reliable information for their further use. In the process of data processing, plans were prepared for the planning and altitude justification of the quarry area and access roads M 1: 5000, the topographic plan of the quarry M 1: 1000 with a relief cross section of 1 m. It is assumed that these studies in the future will allow implementing organizations to reduce execution costs works and will improve economic efficiency in conditions of moving unstable soils.

Application of Dynamic Fragmentation Methods in Multimedia Databases: A Review

Fragmentation is a design technique widely used in multimedia databases, because it produces substantial benefits in reducing response times, causing lower execution costs in each operation performed. Multimedia databases include data whose main characteristic is their large size, therefore, database administrators face a challenge of great importance, since they must contemplate the different qualities of non-trivial data. These databases over time undergo changes in their access patterns. Different fragmentation techniques presented in related studies show adequate workflows, however, some do not contemplate changes in access patterns. This paper aims to provide an in-depth review of the literature related to dynamic fragmentation of multimedia databases, to identify the main challenges, technologies employed, types of fragmentation used, and characteristics of the cost model. This review provides valuable information for database administrators by showing essential characteristics to perform proper fragmentation and to improve the performance of fragmentation schemes. The reduction of costs in fragmentation methods is one of the most desired main properties. To fulfill this objective, the works include cost models, covering different qualities. In this analysis, a set of characteristics used in the cost models of each work is presented to facilitate the creation of a new cost model including the most used qualities. In addition, different data sets or reference points used in the testing stage of each work analyzed are presented.

Analysis of Contracts to Build Energy Infrastructures to Optimize the OPEX

The employer (owner) of the project wants to obtain the maximum profit for the money invested and the consultant (contractor) will try to give less for that money. The regulation of their relationship is based on the contractual agreement, which in the energy sector is mainly based on the engineering, procurement, and construction (EPC) model. The objective of this work was to evaluate which factors should be included in the drafting of contracts, to minimize problems between the parties, and thus minimize execution costs and optimize operation and maintenance costs. Information and data on the integration of operability and maintainability criteria in contracts for 158 projects, with a total contract value of close to €40,000M, were analyzed. Several of those projects corresponded to wind, solar, and hydroelectric plants. The information collected the perception of the agents involved, and was classified according to the experience of the agents consulted in the operation and maintenance areas. Finally, the proposed criteria were prioritized. In general, the owner is willing to introduce these criteria in his contracts if they reduce the operation and maintenance cost by around 1–5%, while the contractor is interested in increasing his probability to be selected by 1–3%.