Preliminary Estimation Method Research Articles

Preliminary Estimation for Software Development Projects Empowered with a Method of Recommending Optimal Duration and Team Composition

In the early software development stages, the aim of estimation is to obtain a rough understanding of the timeline and resources required to implement a potential project. The current study is devoted to a method of preliminary estimation applicable at the beginning of the software development life cycle when the level of uncertainty is high. The authors’ concepts of the estimation life cycle, the estimable items breakdown structure, and a system of working-time balance equations in conjunction with an agile-fashioned sizing approach are used. To minimize the experts’ working time spent on preliminary estimation, the authors applied a decision support procedure based on integer programming and the analytic hierarchy process. The method’s outcomes are not definitive enough to make commitments; instead, they are supposed to be used for communication with project stakeholders or as inputs for the subsequent estimation stages. For practical usage of the preliminary estimation method, a semistructured business process is proposed.

Does androgenic alopecia aggravate the risk of prostate cancer? Evidence from Mendelian randomization

BackgroundEpidemiological reports indicate a potential association between androgenic alopecia (AGA) and increased prostate cancer (PC) prevalence, but conflicting reports also exist. This study aims to elucidate the causality of AGA on PC risk using Mendelian randomization (MR) analysis. Materials and methodsTwo-sample MR analyses utilized public genome-wide association studies summary data for single-nucleotide polymorphisms associated with AGA. Four statistical methods were used: inverse variance weighted (IVW), MR-Egger, weighted median, and weighted mode, with IVW as the preliminary estimation method. Additionally, sensitivity analyses were conducted to address pleiotropic bias. ResultsGenetically proxied AGA did not demonstrate a causal effect on PC risk (IVW P > 0.05). Consistently, complementary methods yielded results aligned with IVW. ConclusionsOur MR analysis indicates no causal relationship between genetically predicted AGA and PC risk, suggesting that observed associations in epidemiological studies may not be causal.

Method for preliminary estimation of the crankshaft rotational speed of a reciprocating hybrid power machine with regenerative heat exchange when operating in compressor and pump modes

The determination of the crankshaft rotational speed of a reciprocating hybrid power machine with regenerative heat exchange when operating in the pump mode at a known angular velocity of the crankshaft and when operating in the compressor mode is considered. Based on the analysis of the working processes of injection and suction and assuming equal maximum pressure losses in these processes, the analytical expressions for determining the angular velocity of the crankshaft when operating in the pump mode with a known angular velocity of the crankshaft when operating in the compressor mode are obtained. In addition, based on the equality of work losses in the processes of injection and suction when operating in the compressor and pump modes, the angular velocity of the crankshaft in the pump mode is determined with a known angular velocity of the crankshaft when operating in the compressor mode. Based on the numerical analysis for the air-water working bodies, the dependences of the rotational speed of the crankshaft when operating in the pump mode on the rotational speed of the crankshaft when operating in the compressor mode and on the discharge pressure were obtained. It is shown that the rotational speed of the crankshaft is 100150 min–1 at the rotational speed of the crankshaft in the compressor mode from 2000 to 3000 min–1. Keywords: reciprocating hybrid power machine, regenerative heat exchange, reciprocating compressor, reciprocating pump, crankshaft rotational speed, discharge pressure. Scherba_V_E@list.ru

АНАЛИЗ ВОЗМОЖНОСТЕЙ ФИЛЬТРУЮЩЕГО РЫБОЗАЩИТНОГО УСТРОЙСТВА ПРИ ГОРИЗОНТАЛЬНОМ РАЗМЕЩЕНИИ КАССЕТ

Problem statement. In accordance with the code of rules (SP 101.13330.2012), the use of fish protection devices with a filter screen and a flushing system applies to water intake facilities in various placement conditions, in this regard, it is relevant to expand the possibilities of using filter cassettes at shallow water depths in the water source.
 Results. A methodology has been developed to substantiate the filler parameters of a horizontal filter cassette in the form of plastic balls and their distribution along its length, as well as a preliminary assessment of the uniformity of flow rates over the area of the filter cassette.
 Conclusions. To improve the operational characteristics of the filter fish-protective device in conditions of shallow water sampling depths, instead of the basic design with a vertical cassette layout, a filter cassette with a horizontally positioned water intake surface and a self-washing effect is recommended, in which a filler made of plastic balls (with positive buoyancy) is used and there is free space for their vertical movement. On the basis of hydraulic calculation, a method for preliminary estimation of filtration rates in such a cassette has been developed. To ensure a uniform distribution of the filtration rates of the water flow along the length of the cassette, it is recommended to use balls of different diameters. Evaluation of the working conditions of the cassette allowed us to obtain a pattern of changes in the diameter of the balls along its length, so for a specific example, the calculated diameter of the balls varied from 8 mm, in the suction nozzle, to 40 mm at the end of the cassette. The technique can be used to calculate the parameters of horizontal filter cassettes of fish protection devices.

Methodological approaches to the use of the law of inertia in the development of socio-economic systems

The relevance of the proposed study is due to the application of Newton’s laws on the determination of speed and acceleration, which reflects the establishment of the actual specific weights of production factors by phases (stages) of the economies’ development of the countries in the world. By applying the laws of physics, the simplest methods have been developed for decomposing the absolute growth of GDP per capita, according to the factors that determine it. A model of economic growth is determined, which is similar in content to Newton’s first law of measuring the paths traveled with uniformly accelerated motion of matter. By calculation, the forecast parameters of the Russian economy can be determined, which determine the GDP per capita until 2030. At the same time, the basic factors of development (45%), investment in fixed assets (35%) and innovative (20%) remain the main factor in the development of global competitiveness in Russia. To do this, you need to gain the proper acceleration. We propose a new approach for assessing the economic stability of socio-economic systems, based on taking into account the mutual influence of the elements of large systems on each other. The novelty of the research lies in the use of the laws of inertia in the development of the economy, since the existing forecasting activity does not provide for obtaining promising changes in the volume and structure of the forecast. As the competitiveness of the countries of the world develops, the share of basic factors such as labor, capital and natural resources decreases significantly (from 50% in the first stage to 40% in the second, and up to 30% in the third stage of economic development). In the stage of high-tech development of the countries in the world, the proportion of factors of innovative development grows up to 30% comparing with 10% in the first two stages of its development. To illustrate the applied value, Newton’s second law was applied as an alternative method for preliminary estimation of the specific weights of three groups of production factors.

The concept of a method of preliminary estimation of groups of sources polluting the air with carbon dioxide

The problem of atmospheric air pollution is well known and it results in negative climate change. To reduce carbon dioxide emissions in a given area, it is necessary to identify the main sources of these pollutants by groups and then estimate the percentage share of each group in the total emissions. The temporary share of individual groups in carbon dioxide emissions is related to many factors, such as seasonality, geographic location of a given town, number of permanent and seasonal inhabitants, the level of activity and the prevailing nature of the industry. Estimating the percentage share of individual groups is difficult due to the lack or difficulty in establishing a lot of information that is helpful or required in the estimation.The article presents a method of estimating the share of individual carbon dioxide sources in air pollution. The authors presented a method for tourist destinations, based on weather conditions, media consumption and the intensity of transport within the city.

The Dependence of Short-Circuit Current in a Transistor Inverter on the Parameters of an Electric Circuit

In the course of the operation of power transistor converters of electric energy, various emergency situations are possible, e.g., a short circuit in the load circuit. The rate of increase in the short-circuit current and its amplitude are affected by the parameters of electric circuit (inductance, power supply voltage of the inverter, control voltage across the gate), as well as by the properties of transistors. A method for preliminary estimation of the short-circuit current and rate of its increase at the stage of designing a converter has been suggested in the paper. This method is based on the theory of planning a multifactor experiment. Calculations of the aforementioned parameters for an inverter with the given technical characteristics have been carried out. A comparison of the results of calculation and physical layout has shown that the suggested approach can be used in the design of any electric energy converters in power semiconductor devices.

BIM-based preliminary estimation method considering the life cycle cost for decision-making in the early design phase

ABSTRACT Prediction of construction cost and life-cycle cost through preliminary estimate is very important for the economic decision-making in the early phase of building projects. However, the conventional preliminary estimate has a high error range and low reliability because it relies only on the basic information of projects. In addition, the consideration of the life-cycle cost of the building is insufficient, causing problems such as budget shortage, inaccurate budgeting, and life-cycle cost increase. In this study, we propose a method of preliminary estimate based on BIM below the level of detail 2 and actual construction cost data to support the decision-making in the early design phase. To verify the proposed method, a web-based prototype was implemented and applied to three test cases. The range of error rate for three test cases was 1.93–7.16% (average error rate: 5.18%). It satisfies the criteria (−30% ~ +50%) of the “American Association of Cost Engineering”. As a result, the feasibility of the proposed model was validated. It is expected to be utilized as useful information in the decision-making occurring in the early design phase, and this allows for a rapid economic review of the design alternatives, a reduced LCC, and a shortened decision-making time.

A preliminary estimation method of Los Angeles abrasion value of concrete aggregates

The main purpose of this study is to develop a preliminary estimation method to predict the Los Angeles abrasion value of concrete aggregates. For this purpose, Los Angeles abrasion tests were performed on the concrete aggregates which were basalt, waste marble and limestone. Five different number of iron balls (6, 12, 18, 24, and 30) in fixed diameters and four different number of revolutions of drum (500, 1000, 1500, and 2000) were used in these tests. After obtained the test results, the response surface method (RSM) was used to investigate the combine effect of the test parameters on the Los Angeles abrasion values. The variables are the number of iron balls, number of revolutions for drum, average saturated surface-dry aggregate density and average water absorption for RSM analysis. As a result, a preliminary estimation method was developed to classify the aggregates according to Los Angeles abrasion values. The developed method can be used to estimate the abrasion values approximately, practically and quickly.

Occupancy modelling of buildings based on CO2 concentration measurements: an experimental analysis

The problem of real-time estimation of occupancy of buildings (number of people in various zones at every time instant) is relevant to a number of emerging applications that achieve high energy efficiency through feedback control. The measurement of CO2 concentration can be considered an important indicator that allows to define the occupation of closed and crowded spaces. Interesting cases can be school buildings and other buildings used in civil and residential (shopping centers, hospitals, etc.). This paper starting from an experimental analysis conducted of a University campus in different operating conditions, with different model for occupancy simulation in multi-zone multi-occupant buildings and its preliminary validation from experimental data acquired in different cases. The acquired data are used to present some graphical models and perform occupancy estimates. Starting from an accurate analysis of the data, attempts are made to define a preliminary estimation method through the development of a mathematical models of occupancy dynamics in a building, which show promising results.

Clinical studies of the effectiveness and safety of antivenoms

In the 1890s, hyperimmune sera proved effective in animals against challenge by the snake venom against which they had been raised. They were first used, apparently successfully, in a human patient in about 1895. Since then, antivenoms have become accepted as the only reliable specific treatment for snake-bite envenoming. Despite decades of accumulated clinical experience and a number of published randomized comparative and observational studies, the clinical effectiveness and safety of some antivenoms remain open to question, due to a lack of robust randomized controlled trial data.Antivenoms in some poorly regulated markets may have high rates of potentially fatal adverse effects and their use must be balanced by demonstrable effectiveness. Even those manufactured to strict regulatory requirements may pose a rare risk of severe adverse reactions.Most antivenoms currently marketed around the world were registered without first being studied clinically. There is increasing pressure to subject antivenoms, even those that are long-established, to the same protocols of rigorous pre-clinical and clinical assessment that are standard regulatory requirements for other drugs. Conventional clinical testing progresses through Phases I, II, III to IV. Most authorities consider antivenoms too dangerous to be used in Phase I studies in healthy volunteers. An alternative method for preliminary estimation of safety, dose-finding and effectiveness, is proposed - the “3 + 3” dose escalation or de-escalation design, in volunteer patients, as used in oncology to test cytotoxic drugs.Antivenoms are so widely used and well trusted, that there are few ethical justifications for placebo controls. However, placebo might be ethically justified if there were no proven effective treatment and or if withholding or delaying treatment posed acceptably negligible risks to the participants.Antivenom trials are most urgently needed in low-to middle-income countries where there are many practical, logistical and funding challenges. Basic requirements for clinical trials include identification of the biting species of snake in every case; the use of objective, clinically-relevant endpoints, such as restoration of blood coagulability; definition of inclusion, exclusion and withdrawal criteria; assurance of antivenom safety; ethical considerations; inclusion of one or more control (comparator) groups; and analysis based on intention to treat. The highest quality evidence comes from Phase II and larger Phase III studies that have been designed as statistically powerful, randomized, controlled trials (RCTs), ideally with blinding of patients and investigators to avoid bias. Because of the challenges to carrying out clinical trials of antivenoms, Phase IV trials (post-marketing surveillance) are potentially more important and useful than for most other drugs.

A Method for Preliminary Estimation of the Length of Midship Body Block to Be Inserted During Ship’s Conversion

Abstract The paper presents a method for preliminary estimation of the length of the midship body block, which inserted in the original hull, increases the deadweight of the ship in line with a required quantity. The method may be useful for establishing the scope of conversion to better adjust the ship for transportation tasks. The problem is formulated by using a mathematical model so selected that its solution, under set of assumptions, is obtained in a closed analytical form. The presented method can be useful for application to pre-investment analysis of the ship conversion costs and functional profits.

METHOD FOR DETERMINATION OF ENERGY DEMAND FOR MAIN PROPULSION AND ONBOARD ELECTRIC POWER FOR MODERN HARBOUR TUG BOATS BY MEANS OF STATISTICS

The paper presents the method of preliminary estimation of harbour tugs main propulsion power and on board electric power station based on statistical analysis. At the beginning of paper, the classification of tug boats is executed. Tug boats are classified according to their type of service, type of main propulsion, equipment and way of service. For harbour and roadstead tug boats, the analysis of main propulsion plants and on board power station is executed. Pushing and tractor propulsion plants are presented in which different types of thrusters i.e. azimuth, cycloid and classic propellers are analysed. Advantages and defects of each type of main propulsion are pointed. Statistic methods of analysis are elaborated in Department of Marine Propulsion Plants of Gdynia Maritime University. These methods make possible in simple and quick way to estimate parameters of ship energetic system. The estimation is carried out with good correlation coefficient and high determination of regression coefficient. Statistic methods make also possible to forecast energetic systems parameters for ships to be built in the future. Dependencies for main propulsion power and electric power of onboard power station are not universal for all types of ships. They should be elaborated separately for each type of ships. In this paper, the results concerning only harbour and roadstead tug boats are presented.

Void distributions and permeability prediction for rotationally moulded polymers

An experimental study of void distributions for rotationally moulded polyethylene is presented. The effects of key variables such as maximum process temperature and nominal wall thickness (via powder mass) are studied. Analytical models and finite element mass diffusion models for the permeability of heterogeneous polymers with air voids are presented and comparatively assessed. The FE method allows modelling of realistic (measured) void distributions. A preliminary estimation method for void volume fraction and mean void radius is presented. This approach is based on hot plate measurements and is shown to give good correlation with the rotationally moulded material for different process temperatures. Key objectives of the present work are (i) to develop an understanding of the factors affecting gas permeability in rotationally moulded polymers and (ii) to develop experimental and computational methods to help design low permeability rotomoulded polymer liners.

Accuracy Verification of a New Couette Rheometer

By utilizing the newly developed visual Couette rheometer with its outer cylinder rotating and pressure adjustable, cavitation experiments of strong shear flow are carried out. It is found that the influence of transient temperature and shearing torque on shearing cavitation is very obvious. By experimental data of temperature step response of sensor, the convection heat transfer coefficient when the thermocouple is rooted in resting hot liquid and subjected to the step temperature change is obtained. In a cylindrical coordinate system, with the pure shearing torque and transient heat transfer differential equation obtained from the experiment, the transient temperatures of strong shearing Couette flow at different time are calculated by using numerical method. The theoretical value is consistent with the experimental result, thus showing the correctness of pure shearing torque and transient temperature and the uniformity of gap obtained from the said Couette rheometer by using the preliminary estimation method, the temperature change value of strong shearing Couette flow is obtained. The comparison and analysis results show that the proposed method is highly accurate and widely applicable.

Effect of NaCl, Na2SO4, and mannitol on utilization of storage starch and formation of plastids in the cotyledons and roots of alfalfa seedlings

Utilization of storage starch in the cells of cotyledon mesophyll and root meristem in the course of alfalfa (Medicago sativa L.) seed germination on the solutions of NaCl, Na2SO4, and mannitol at different concentrations and identical osmotic pressure was investigated using the method of transmission electron microscopy. Ultrastructural analysis showed changes in the number of starch grains and deceleration of chloroplast development depending on the osmotic component of salt influence. At low concentrations corresponding to osmotic pressure of 202.6 kPa, Na2SO4 did not affect the formation of the photosynthetic machinery and utilization of starch inclusions; mannitol contributed to the preservation of considerable reserve of starch without disturbing the development of chloroplasts; NaCl did not inhibit the development of the photosynthetic machinery and induced an increase in the number of starch grains presumably at the expense of newly produced starch. When the concentration of the investigated substances increased up to the values corresponding to the osmotic pressure of 607.8 kPa, NaCl did not suppress transformation of amyloplasts into chloroplasts and utilization of starch; Na2SO4 inhibited the development of chloroplasts and starch utilization; mannitol decelerated transformation of amyloplasts and inhibited mobilization of starch grains. The obtained results make it possible to propose a method of preliminary estimation of tolerance of dicotyledons to abiotic stresses based on the cytological analysis of utilization of starch grains and formation of photosynthetic compartments of chloroplasts in the mesophyll of cotyledons.

Return on environment

The Return on Environment (ROE) is developed, and tested, as an objective indicator to support the results of Life Cycle Assessments. It is based on the observation that a ratio of life cycle costs incurred throughout the extraction, transport, manufacturing, use and disposal stages, to the selling price, appears to scale linearly with a quantitative impact assessment. ROE is therefore a normalization method which permits comparison of new assessments with existing data, even from products with quite different characteristics. It can, alternatively, be applied to estimate either the life cycle cost, or quantify environmental impact, provided the other is known. Like its economic cousin, the return on investment, cases studied typically have ROEs in over the range of 2–20%. ROE is intended as a preliminary estimation method, akin to engineering costing, which has a precision of +-30%. As such, it can be used to rapidly determine if a more detailed cost assessment can be justified and, if so, where the efforts should be oriented. ROE is a measurable life cycle index intended to render LCAs more suitable for decision making. A further benefit that ROE provides is the guidance to a life cycle practitioner, or product development team, to assess if sufficient data has been collected, or if costs and impacts have been over or under-estimated. It has advantages over specific ecoindicators, such as manufacturing energy or waste emissions, which are both product specific and subjective. The Return on Environment also serves as a systematic index for reporting improvements or as a relative environmental rating.

Influence of diffusive processes on the border metal-lubrication upon the development of not permissible kinds of weary

Considered is method of the lubricant tribo-technical features on the basis of parameters registered under unstable operating conditions of tribo-technical systems with local contact. The following experimental results are obtained: the influence of unstable modes of operation and physic and mathematical features of thin blanket of the process of lubrication organization for different groups of lubricants. The developed method of preliminary estimation of lubricant tribo-technical features is based on obtained results mentioned above

A method for preliminary estimation of solid oxidation kinetics and mechanism

The possibility of preliminary estimation of the oxidation kinetics and mechanism using the quantity to from the exponential kinetic rate equation is discussed.

Ultrasonic pelvimetry. A method for preliminary estimation of the pelvic outlet

Vaginal sound, with transmitter crystals of 2 MHz, is used when measuring the interspinous diameter. The echo from the pelvic wall, the effect on the measured spinal diameter by altering the position of the ultrasonic transmitter, and the influence of air or faeces between the ultrasound transmitter and the pelvic wall, have been analysed in a series of model trials on a dummy submerged in water. Thereafter clinical trials were performed on 102 women, pregnant in their 9th month. The results obtained when measuring the interspinous diameter on the ultrasonic tomogram were compared with the results obtained when measuring the same distance on a frontal x-ray picture taken using the orthographic technique according to Borell-Frenström. The method is suitable for selecting those cases with suspect constriction of the pelvic outlet for an x-ray examination by the Borell-Fernström technique.