Noise Meter Research Articles

26 Investigating Noise Exposure to Newborn Infants with Respiratory Support: Methodological Considerations

Abstract Background Excessive noise in the NICU may lead to serious long-term effects on hearing impairment and sensory development in newborns. As such, the maximum recommended noise level is 45 dBA. Reported studies regarding noise exposure of ventilated preterm infants show inconsistent results; however, these studies also vary considerably in their methodology in terms of noise ascertainment (Table 1). We hypothesize that the study methodology significantly influenced data quality. Objectives Our aim is to investigate if measured ventilator noise levels from previous literature could potentially be the result of methodological shortfalls of the study design rather than perceivable noise levels. Design/Methods A ventilator circuit was set up using nCPAP and high frequency mode with nasal prongs. Noise levels were measured using a commercially calibrated noise meter. Three different scenarios were tested. (1) Measurements were taken at different angles of (0°to 180°), with 180° facing the end of the nasal prongs, without a mannequin, with the membrane/orifice of the noise meter placed 2 mm laterally from the prongs. (2) Noise levels were measured at 180° at distances of 0 to 20 mm from the nasal prongs. (3) Measurements were taken in the oral cavity of a life-size intubation mannequin of a newborn baby. Results Overall, the noise levels produced at different settings varied significantly, ranging from 45.7 dB to 82.2 dB. The average environmental background noise was 44.4 dB. Noise levels typically increased as the angle increased, with the highest noise level at 180° for both high frequency and nCPAP mode, at 58.4 dB and 58.2 dB, respectively (Figure 1). Noise levels recorded at high frequency were slightly higher than nCPAP values. Furthermore, in regards to distance, the highest mean value, 82.2 dB was recorded with the noise meter approximately 3 mm from the nasal prongs, with the lowest mean value, 47.6 dB, being recorded at ~20 mm. During trials with the mannequin, the lowest value, 50.1 dB, was recorded at the entrance of the mouth with slightly higher values being recorded within the oral cavity. Conclusion The results indicate that small changes in experimental settings, such as positioning and distance from the nasal prongs, can greatly influence noise levels, particularly above the recommended levels for neonates. In summary, some study results are potentially influenced more by the study design than the device type or ventilator setting. Further research and detailed reporting in the NICU is recommended.

Разработка шумозащитного костюма для снижения воздействия шума на работников молокоперерабатывающей отрасли на примере промышленных предприятий Республики Мордовии

In the work, a study was made of harmful production factors affecting a worker in the dairy industry. It established that in the modern production of dairy products, high-performance technological equipment is used, the operation of which leads to the appearance of hazardous and harmful production factors. Noise is not the last among them. The degree of negative impact of noise on people depends on its frequency range, intensity, duration of action and the nature of the personnel work. The zones of the greatest non-specific effect of noise on a person are identified. It is established that the operator of the dairy industry is in close contact with the process equipment. The most suitable solution for protecting personnel from noise is the use of personal protective equipment. The article evaluates the noise impact on the operators of the dairy processing industry of the Republic of Mordovia within the framework of a special assessment of working conditions using the Assistant noise meter of the first accuracy class. Exceeding the noise level is observed at all the same type of workplaces. To protect workers from increased noise, a noise protection suit was developed, consisting of a jacket, and trousers. Experimental studies of the noise-protective properties of this suit were carried out at the Department of Life Safety of FGBOU VO «Moscow State University nabbed after N.P. Ogarev» with the use of modern reverberation chamber BZD-16. This suit differs from the standard overalls in the presence of additional noise-protective inserts that allow to protect the most vulnerable parts of the worker body from the aggressive effects of noise.

Evaluation and spatial noise mapping using geographical information system (GIS): A case study in Zaria city, Kaduna State, Nigeria

Background: Spatial noise level mapping using a geographical information system (GIS) is essential for the visual colour representation of noise analysis, which is a necessity for strategic planning and mitigating measures. Methods: Extech noise meter (model 407750) was used for sound measurement and a GIS (inverse distance weighted) was used in 54 study locations for the spatial interpolation. The study was classified into five categories based on Nigeria’s WHO standard and National Environmental Standards and Regulations Enforcement Agency (NESREA). Results: For the LDAY (D),LEvening (E), LNight (N), and LDEN, all the locations exceeded the WHO standard while 94.4%, 90.7%, 83.3%, and 83.3% of the locations exceeded the NESREA standard. The LDay (D) ranged from the minimum value of 67.6 dB (A) at the Ijaw residential area to the maximum value of 93.0 dB (A) at Kwangila site (1) intersection. The LNight ranged from the minimum value of 63.3 dB (A) at Dogorawa residential area to the maximum value of 92.1 dB (A) at Kwangila site (1). The LDEN ranged from the minimum value of 73.1 dB (A) at Hanwa residential areas to the maximum value of 97.2 dB (A) at Kwangila site (1). The noise quality rating ranged from satisfactory to unallowed noise quality grading. The selected intersections and residential areas with light commercial activities had the highest and lowest noise levels, respectively. Conclusion: Efficient maintenance of silencers, planting trees with dense foliage, and strategic planning would be necessary panacea in curbing excessive noise.

Calibration of an RF/Microwave Phase Noise Meter with a Photonic Delay Line

The main advantage of phase noise meters with photonic (fiber) delay lines is that they do not require high-performance, low-noise reference oscillators. On the other hand, some additional calibrations are required, which are the subject of this paper. First, the quadrature must be maintained on the mixer by precise adjustment of the phase and/or delay. Next, since the response of the mixer is proportional to the square of the input test signal, a precise amplitude calibration is required. Finally, the frequency response of the FFT spectrum analyzer and its corresponding anti-aliasing low-pass filter needs to be known precisely. In this paper, to the best of our knowledge, we present innovative solutions for all three calibrations. All three calibrations were built in and tested in our phase noise meter. The result is a simple and robust phase noise meter suitable for non-laboratory environments.

Noise reduction in the neonatal intensive care unit: An exploratory study

PurposeTo assess nurses' knowledge and perspectives on the impact of excessive noise exposure on infants’ neurodevelopment, and on the clinical utility of a noise meter. MethodsAn online and written survey was administered to 66 nurses in a level II-III NICU pertaining to nurses’ demographic, perception of noise, and efficacy of a noise meter. Quantitative and qualitative responses were descriptively and thematically analyzed, respectively. ResultsA total of 32 (49%) nurses responded, of these 24 (75%) were aware of the risks associated with exposure to excessive noise on infants' neurodevelopmental outcomes, and almost half believed that the noise meter was not an effective noise reduction intervention. Conclusion: There is an increased need to further educate NICU staff regarding the negative effects of excessive noise on infants’ neurodevelopment, and to provide ongoing feedback on sound levels in the NICU to empower staff to enact sustainable noise reduction interventions.

Mobile Device-Based Train Ride Comfort Measuring System

As an important train performance quality, comfort depends on vibration and noise data measured on a running train. Traditional vibration and noise measurement tools are facing challenges in terms of collecting big data, portability, and cost. With the continuous upgrade of mobile terminal hardware, the built-in sensors of mobile phones have the ability to undertake relatively complex data measurement and processing tasks. In this study, a new type of train comfort measurement system based on a mobile device is developed by using a built-in sensor to measure the vibration and noise. The functions of the developed system include the real-time display of three-way vibration acceleration, lateral and vertical Sperling indicators, sound pressure level, and train comfort-related data storage and processing. To verify the accuracy of the mobile device-based train ride comfort measuring system (DTRCMS), a comparison of test results from this system and from the traditional measuring system is conducted. The comparison results show that the DTRCMS is in good agreement with the traditional measuring system. The relative error in three-direction acceleration and Sperling values is 2~10%. The fluctuation range of the noise measured by DTRCMS is slightly lower than that of the professional noise meter, and the relative error is mainly between 1.5% and 4.5%. Overall, the study shows that using mobile devices to measure train comfort is feasible and practical and has great potential for big data-based train comfort evaluation in the future.

Spatio-temporal variability of vehicular traffic, noise and temperature of Minna City, Niger State, Nigeria

This study investigated spatio-temporal variability of vehicular traffic noise and temperature of Minna city, Niger State. The study used the 15 minutes Septa-Square technique to count the number of vehicles across the purposively selected junctions and round-abouts. The Noise Meter Level (Dosemeter) was used to generate the vehicular traffic noise at the selected junctions and roundabouts. The thermometer was used to capture the hotness of the selected roundabouts and junctions. The result of the study showed that Tunga Roundabout had 7032 vehicular counts, which was the highest vehicular traffic flow in the city. Barago Roundabout had 93.4dB recorded as the highest noise level and Tunga Roundabout recorded 360C as the highest temperature reading. The afternoon and evening had the highest records of vehicular traffic flow, increased traffic noise level and the temperature readings. The study recommended the construction of flyover to reduce traffic flow especially at Tunga and City Gate roundabouts. It recommended the construction of link roads to divert traffics to other parts of the city, plant trees at the roundabouts and junctions in order to cushion the effects of high temperature without further delay.

Aplikasi Styrofoam Sebagai Absorpsi Bunyi

This study aims to determine the level of sound attenuation of Styrofoam material. T his research is using a noise meter application Decibel X: dB Sound Level Meter and a sound generator as a sound source. Then Styrofoam as an acoustic material with a thickness of 1 cm; 1.5 cm; 2 cm; 2.5 cm ; 3 cm; 3.5 cm and 4 cm. The average absorption coefficient obtained in this study with a material thickness of 1 cm is 0.023. Then the average absorption coefficient at a thickness of 1.5 cm is 0.031. While the average absorption coefficient at a material thickness of 2 cm is 0.040. Furthermore, the average sound absorption coefficient at a thickness of 2.5 cm and 3 cm has the same value, namely 0.039. Then, the average sound absorption coefficient at a thickness of 3.5 cm and 4 cm also has the same value, which is 0.038. Based on the research that has been done, it can be concluded that sound absorption at frequencies below 1000 Hz occurs significant sound absorption. At frequencies of 200 Hz, 400 Hz, 600 Hz and 800 Hz, the average sound absorption increases from 1 cm to 3.5 cm of Styrofoam thickness. While the thickness of Styrofoam 4 cm on average did not show a significant increase in sound absorption. Styrofoam thickness of 4 cm can effectively absorb sound at a frequency of 1000 Hz only.

NOISE POLLUTION OF THE MAIN STREETS THE CENTRAL PART OF THE CITY OF LVIV

Introduction. The modern process of urbanization is accompanied by a steady trend towards increasing the level of motorization. And both public and private. The concentration of a large number of vehicles in a relatively limited area of the city leads to the dominant impact of transport on the noise state of the territory. The flows of road transport in modern cities are the main source of generated external noise and create an environmental problem of noise pollution with different levels of load on urban areas. Solving the problem of noise pollution created by road traffic is one of the complex tasks of sustainable development of modern cities. The problem of noise pollution is especially relevant for narrow main streets with old buildings in the central areas of modern cities. In the lack of regular monitoring of noise pollution in urban ecosystems, many threats to the health of urban residents. Therefore, a systematic study of noise levels in such areas allows deepening knowledge about the modern environment of human life and its dangerous factors.Purpose. The study was to establish the levels of noise pollution on the main streets of the central part of Lviv from traffic flows to assess the environmental conditions of urban areas.Methods. Measurements of noise levels were carried out directly on the sidewalks of main streets with medium traffic intensity in daylight with the accounting of vehicle categories and the use of digital noise meter brand Benetech GM 1356.Results. At the time of the research in the research areas, there were more than 2 thousand cars per hour. The share of cars in the traffic flow of main streets is predominant (over 80%). According to the results of measurements of noise levels in the studied areas of the streets exceeded the permissible standards (Lec. Add., DBA), established for areas directly adjacent to residential buildings, health care facilities, children's preschools, schools and other educational insti-tutions, libraries, temples, museums and shopping malls. Exceeding the acceptable norms of noise pollution on ave. V. Chornovola street is from 15 to 19 dBA, on the street. Gorodotskaya - from 23 to 28 dBA.Conclusions. Noise levels in the study areas exceed the permissible pollution levels by 27% or more. A high positive correlation was established between the noise level and the intensity of vehicles in the flow. The results of high noise levels in public areas are a cause for concern. To solve the problem of noise pollution, the most effective measure is to limit the entry of cars into the central part of the city.

Assessment of the status of techniques to attract farming swiftlets (Aerodramus fuciphagus amechanus) and noise impacts of the speaker intension of swiftlet farming houses in key area in Ho Chi Minh City

This paper presents the results of assessing the status of techniques to attract swiftlets, technology to operate swiftlet houses by PRA method combined with direct survey of swiftlet houses in key areas in Ho Chi Minh City. The results show that the number of swiftlet houses is concentrated mainly in Can Gio district with 481 swiftlet houses, method of attracting swiftlets in which the combination of sound and feces accounts for the highest proportion of the methods with 37.14%. The most used sound is the sound of flock of swiftlets, which is used outside with 74.29%, the cry of a baby bird (lullaby) is used the most inside with 74.29%. The number of households that play the loudspeakers daily inside is 94.29% and the playing time is 19.84 hours. While the external speaker is 91.43% and the playing time is 12.17 hours, the sound system originates from Vietnam and Malaysia. Most of the swiftlet houses have a temperature measurement system (82.86%) and most are automatic (77.14%). The assessment of the noise level from the loudspeaker for the swiftlet house by a hand-held noise meter SL4202 that measures the noise according to Vietnamese Standard TCVN 7878-1:2008 shows that the average noise level in the swiftlet house area in Can Gio and Long Phuoc commune, district 9 is 1.1 and 1.4 DBA higher than QCVN 26, respectively.

Анализ дигрессии и оптимизация экологической составляющей на примере развивающихся районов Тюмени

In this study, there was investigated the level of environmental safety regarding the noise pollution and the presence of harmful substances in the atmosphere in the developing residential neighborhoods of Tyumen. With the help of specialized devices (noise meter, vibrometer, analyzer SVAN 912M and bellow aspirator AM-0059), it was proved that the permissible values of noise pollution and emissions of harmful substances from motor transport are exceeded. To solve these problems, various kinds of measures are proposed: construction, organizational and technical, constructive and others with an assessment of the effectiveness of their application.

ASSESSMENT OF NOISE LEVELS IN RUMUOKORO MOTOR PARK IN RIVERS STATE, NIGERIA

The study was aimed at determining the level of noise pollution in a motor environment. Noise level in the Rumuokoro motor park was measured with a type II noise meter called Sound Level Meter GM1352. The study involved field noise Measurements which were carried out at five established points around Rumoukoro motor park during morning, afternoon and evening time periods. The minimum mean and maximum mean noise levels for morning time periods were between 74.8 dB(A) and 86.3 dB(A) respectively. The afternoon time periods showed a minimum mean noise level of 75.7 dB(A) and a maximum mean noise level of 82.7 dB(A); while the evening time periods mean noise levels were between 74.8 dB(A) and highest of 86.6 dB(A). Thus, noise levels in the morning and evening time periods recorded higher noise levels than the afternoon time periods. The result of this study showed that the measured level of noise exceeded the international standards (WHO and USEPA) and national standards (NESREA and FMENV) in monitoring noise level in the environment.

Mapping and distribution of noise using IDW interpolation algorithm in Thuan An city, Binh Duong province

The study is conducted to assess the level of noise pollution from traffic activities in urban areas (in the case of Thuan An city, Binh Duong province) with the specific goal of applying geographic information systems. (GIS) in building noise pollution distribution maps in the study area. The research team collected noise data at peak hours and normal hours on weekdays and weekends using noise meters at 61 survey points. Noise measurement data was then interpolated using IDW (Inverse Distance Weighting) method to assess the spatial distribution of noise in Thuan An city. In addition, the study digitizes traffic routes and special areas (hospitals, schools, churches - pagodas) in the study area to identify areas affected by sound noisy. The results show that the areas near the main road are most affected by noise during rush hour, while areas in the small lane are noise level within the permitted range. In addition, the results also show the difference in noise level and noise time between weekdays and weekends.

Traffic noise research in tambov city

Introduction. The problem of traffic noise on the road network of cities is considered. The reasons for the annual increase in the sound level on urban roads in Russia and abroad, as well as the factors contributing to this, are investigated. The purpose of the work: on the basis of the conducted theoretical research and the obtained experimental data, to develop measures that contribute to improving the environmental safety of the city, to build a model of the dependence of the noise level on the traffic intensity, taking into account the peculiarities of the organization of traffic and urban planning in Tambov.Materials and methods. Sound level measurements on the Tambov road network were carried out in accordance with the methodology specified in GOST 20444-2014, which provided for the assessment of the actual noise characteristics of traffic flows (by vehicle type). The measurements were carried out using a noise meter in summer and winter during peak and inter-peak times on weekdays.Results. The study of the noise level on the Tambov street and road network showed an excess of this indicator relative to the norms by 7-18%, depending on peak and inter-peak time, as well as the summer and winter period. The dependence of the traffic intensity of vehicles on the noise level in the summer and winter periods is constructed.Discussion and conclusion. The measures were proposed, including urban planning, to reduce the sound level in the areas under consideration. The complex of these measures will reduce the level of traffic noise on the city’s road network by an average of 5-15 dBA.

The Effect of Noise Meters Giving Visual and Auditory Alarms Used on Reducing Noise in Neonatal Intensive Care Unit

The Effect of Noise Meters Giving Visual and Auditory Alarms Used on Reducing Noise in Neonatal Intensive Care Unit

Investigating Noise Exposure to Newborn Infants From Respiratory Support: Methodological Considerations.

Background and objectiveExcessive noise in the neonatal intensive care unit (NICU) may lead to serious long-term effects on hearing and sensory development in newborns. As such, the maximum allowed noise level is 45 A-weighted decibels (dBA). Studies regarding noise exposure to ventilated preterm infants show inconsistent results; however, these studies also vary considerably in their methodology in terms of noise ascertainment. We hypothesized that the study methodology can significantly influence data quality when measuring noise levels. In this study, we aimed to investigate whether the variations in ventilator noise levels in NICUs could be a result of methodological differences in study designs.MethodsA ventilator circuit was set up using nasal continuous positive airway pressure (nCPAP) and high-frequency (HF) modes with nasal prongs. Noise levels were measured using a commercially calibrated noise meter. Three different scenarios were tested: (1) measurements were taken at different angles (0° to 180°), with 180° facing the end of the nasal prongs, without a mannequin, with the membrane/orifice of the noise meter placed 2 mm laterally from the prongs; (2) noise levels were measured at 180° at distances of 0-20 mm from the nasal prongs; (3) measurements were taken in the oral cavity of a life-size intubation mannequin of a newborn baby.ResultsOverall, the noise levels produced at different settings varied significantly, ranging from 45.7 dB to 82.2 dB. The average environmental background noise was 44.4 dB. Noise levels typically increased as the angle increased, with the highest noise level recorded at 180° for both HF and nCPAP modes, at 58.4 dB and 58.2 dB, respectively. Noise levels recorded at HF were slightly higher than nCPAP values. Furthermore, with regard to distance, the highest mean value, 82.2 dB, was recorded with the noise meter approximately 3 mm from the nasal prongs, and the lowest mean value, 47.6 dB, was recorded at ~20 mm. During trials with the mannequin, the lowest value, 50.1 dB, was recorded at the entrance of the mouth with slightly higher values being recorded within the oral cavity.ConclusionThe results indicate that small changes in experimental settings, such as positioning and distance from the nasal prongs, can greatly influence noise levels, particularly above the recommended levels for neonates. These differences may be attributed to wind-generated noise. In summary, some study results are potentially influenced more by the study design than the device type or ventilator setting. We recommend further research and detailed reporting in the NICU to gain deeper insights into the topic.

Prediction of Road Traffic Noise by CRTN Model in a Sub-Urban Town of India

Present study was undertaken for assessment of spatial characteristics of road traffic noise at varying intervals viz early morning (8-9 am), late morning (11-12 pm), afternoon (2-3 pm) and evening (6-7 pm) time at ten important locations (near school building) of G. T. Road which is passing through the Burdwan town. Digital noise meter was used for recording the traffic noise and noise contour map was constructed by using Geographical Information System (GIS). The recorded data revealed that the highest and lowest average noise 67.1 dB (A) and 86.9 dB (A), respectively. The results revealed that the performance of the CRTN model in both afternoon and evening time for predicting noise level near school building with a coefficient of determination (R2) are 0.536 and 0.544 and a mean difference of - 1.19 dB (A) and - 0.48 dB (A) between the measured and predicted values respectively. Similarly, Pearson statistics also revealed the strong correlation between measured and predicted noise level at afternoon (r = 0.732, p < 0.016) and evening time (r = 0.744, p < 0.014). However, the predicted traffic noise during early morning and late morning hour are less than 0.5. These low values are due to irregular traffic speed, traffic density and irregular building height are the appropriate reasons for low accuracy in predicting model. Finally, it may be suggested that CRTN model can be a decision tool for predicting equivalent noise level in the city like Burdwan.

Survey on present status of noise exposure of workers in metal processing industry

Objective: To investigate the distribution of noise exposure between non-steady state noise and steady-state noise for metal processing workers, which will provide scientific basis for the prevention and treatment of noise hazards in metal processing industry. Methods: The cross-section method was used to investigate the noise exposure of 737 workers from three metal processing industries in Zhejiang Province from October to December 2017. The general demographic information and occupational history were collected by questionnaire. The noise was recorded by individual noise meters, and the noise exposure intensity (equivalent continuous A-weighted noise exposure level normalized to an 8 h-working-day, L(Aeq, 8 h)) and kurtosis were calculated. Results: Workers exposed to noise in the metal processing industry were mainly 18-40 years old (527 workers, 71.51%) , men (570 workers, 77.34%) , and junior high school education background (416 workers, 56.45%) . There were 572 workers (77.61%) with noise exposure intensity (L(Aeq, 8 h)) greater than 85 dB (A) , 558 workers (75.71%) exposed to non-steady state noise (kurtosis ≥4) , and 634 workers (86.02%) with exposure duration less than 8 years. Among the 30 work types investigated, the work types with noise intensity reaching 100% were the stamping, welding and others from a children's car manufacturing factory in Ningbo, operating, chamfering, tapping, and thread rolling from an automobile parts manufacturing factory in Ningbo; The work types with a rate of 100% exposed to non-steady state noise were the grinding from a children's car manufacturing factory in Ningbo, assembling, assembly operating and others from an automobile brake manufacturing factory in Wenzhou, and polishing from an automobile parts manufacturing factory in Ningbo. Conclusion: Metal processing workers have a high rate of over-standard exposed to high noise intensity and a high proportion exposed to non-steady state noise. It is necessary to take sound insulation and noise reduction engineering control, and strengthen personal protection and occupational health management measures to prevent and control the noise hazards.

Noise Level in Textile Industries: Case Study Al-Hillah Textile Factory-Company for Textile Industries, Al-Hillah-Babylon-Iraq

In this study, Al-Hillah Textile Factory, in Al-Hillah city-Iraq follows to State Company for Textile Industries was selected to study the intensity of noise in 2014. Measurements of the noise level were carried out in different workshops for each of the production stages including the spinning machinery workshop (parts 1 and 2), the rotating machinery room, the preparations room, and the textile machinery room (Roti model), weaving machines: Techmash model room Russian-made model room, Sheets’ machinery room, and operator machines room; using two noise meters (model 2237 Fulfici). Fifty samples were collected in each part of these rooms to give realistic results for the noise level. After recording the noise level data, the highest and lowest values and the average of noise intensity readings were calculated in each of the rooms and compared with the global standards permitted by the EPA for industrial facilities. The results of this study showed that the general rate of noise intensity in all rooms exceeded the permissible limits, which impose a noise level of 65-70dB for such industrial establishments according to EPA recommendations in 2008.

Linear stochastic distributed model of moneyaccumulation in the form of a state space

The article deals with the problem of the passive parametric identification of systems for modeling the evolution of money savings income and expenses of one household using a linear stochastic distributed model in the form of a state space taking into account white noises model of the investigated object dynamics’ and white noises of the linear model measuring system of a distributed type. The use of the finite difference method allowed reducing the solution of partialdifferential equations to the solution of linear finite difference system with private derivatives to be reduced to the solution of a system of linear finite-difference and algebraic equations represented by models in the form of state space. It was proposed the use of a Kalman filtering algorithm for reliable evaluation of object behavior. The statement of the problem of estimating the coefficients of the equation of evolution of money savings income and expenses of one household is given. The structure of household income and expenses is described, taking into account additional additive white noise meters. An algorithm for numerical approbation of method for solving the problem of estimating the coefficients of an equation in the form of the state space for the evolution of money savings income and expenses of one household is considered. Calculations were carried out using the Matlab mathematical system based on statistical data for five years, taken from the site “Agency for Strategic planning and reforms of the Republic of Kazakhstan Bureau of National statistics”. The proposed method for solving the problem of coefficients assessment’s passive identification using the equations of money savings for one household in the form of a state space is sufficiently universal. Key words: linear finite-difference equation, model in the form of a state space, evolution of one household money savings, passive identification, Kalman filter, prediction estimates, filtering estimates.