Darbe yra analizuojama GPS veikimo principai nuo palydovų iki pat naudotojui pasiekiamų signalų. Nagrinėjant šiuos principus visur atsižvelgiama į galimas paklaidas ir tiriama kokiu būdu jos yra taisomos, siekiant sistemą padaryti kuo tikslesnę. Atlikus sistemos veikimo analizę daromas bandymas, siekiant nustatyti realiai gautų GPS duomenų paklaidą, matuojant taško poziciją. Taip pat tiriama skirtingų gamintojų GPS imtuvų tikslumo priklausomybė nuo imtuvo procesoriaus kanalų skaičiaus. Paaiškėja, jog rinkoje parduodami GPS imtuvai dirba labai panašiu tikslumu. Toliau darbe atliekama naudojamų GPS duomenų tikslinimo algoritmų analizė ir pasiūlomas judėjimo rastriniu žemėlapiu algoritmas pozicijos nustatymo paklaidų mažinimui bei judėjimo prognozavimui nutrūkus ryšiui su palydovais. / This paper is a study of GPS operating principles from satellites to user-accessible signals. The examination is done by taking into account all the possible errors and how they are corrected in order to make the system more accurate. After system operation analysis tests of GPS data accuracy are made. The position of a point is measured using several GPS receivers. Those receivers are made by different manufacturers, so we can observe the dependency of accuracy according to manufacturer and different number of processor channels. It appeared that receivers have very similar errors. The work is continued by data accuracy improvement algorithms analysis. Finally an algorithm is suggested to improve positioning data precision moving on map and predict the event of a failure to communicate with satellites.

E. Janavičius „Surface position errors formation for axel type parts”. Mechanical Engineering Master‘s Theses / Leader ass.prof J.Rimkus; Siauliai University, Chair of mechanical Technology. – Siauliai, 2006 – 31p. The investigation work „Surface position errors formation for axle type parts�� consists of 28 figures, 5 references. Subject of investigation is surface position errors of the parts. Aim of the investigation is formation of surface position errors in manufacturing process. Axel type parts surface position errors formation during treatment, are presented in the work. The surface position error chains are made with a help of graphs. It is hard to estimate what will be the eventual measurement after the part is fully made, because of the errors that appear in the manufacturing process. In this work were analyzed what surface position errors appears and disappears and witch stays after manufacturing process is over. Using graphs and incidentic matrix were analyzed different surface position errors occasions.

GENERAL CHARACTERISTIC OF THE DISSERTATION Topicality of the problem Prosthesis in orthopaedic technique are constructions that act as leg function reproduction and for external normal view of the leg. It is a technique giving a possibility to adapt to the society and live a full-fledged life, when one or another limb is lost. By the data, declared by the world health society, people with a disability include 10 % of all world population, among them people over 80 years old. More and more orthopaedic techniques are produced in Lithuania at present. The production, manufactured in our country keeps in step with world design and quality in foreign countries and they are 5–6 times cheaper. The main aim of the designers and constructors of orthopaedic techniques is to design and produce functional and high quality lower limbs prosthesis and apparatus. In the meantime, the same as abroad, in Lithuania the production processes of the prosthesis are automated but not so much to ensure a good quality of the prosthesis. Sometimes it is very hard to make prosthesis of adequate size to a patient that prosthesis implicitly fits just to the patient. Also, it is very hard to adjust it, ensuring the same length as the residual limb which should precisely correspond to the lost limb of the changeable loads chains of the prosthesis periodically are deformed during walking. In other words, the length of the prosthesis changes during gait. Thus, it is very important to set the limits of... [to full text]

Kadastriniai matavimai - tai žmonių nuosavybės ir teisingumo garantas ateičiai. Tik apytikslių matavimų buvimas (juosta ar "sieksniu"), kvalifikuotų darbuotojų trūkumas bei skubota žemės reforma šiandien kelia nemažai problemų, susijusių su žemės sklypo ribų bei ploto tikslumu. Atlikus kadastrinius matavimus ir parengus juridinius dokumentus, žemės savininkui garantuojama, kad jo žemės sklypo ribos, plotas bei naudmenų sudėtis yra tikslūs ir suteikia visas teises į nuosavybę Lietuvos Respublikos įstatymų numatyta tvarka. Atliekant pakartotinius matavimus, nustatomi palyginti dideli žemės plotų ir kadastro duomenų pokyčiai. Vidutinis nuokrypis 75 % analizuotų žemės sklypų neviršija leistinosios paklaidos ir lygus 0,06 %. Likusioje 25 % žemės sklypų vidutinis nuokrypis yra 18,65 % ir dėl to būtina tikslinti pradinius duomenis, kurių pagrindu suformuoti arba įteisinti nuosavybėn žemės sklypai. / The cadastral survey is the guarantee of ownership and justice to people for long future. The confidence to approximate survey (tape or “sagene”), the lack of skilled workers and hasty land reform today make a lot of problems, which are connected with precision of land plot boundaries and area. The landowner has a guarantee that his land plot boundaries, area and structure of lands are precise only after making cadastral surveys and preparing juridical documents. According to the law of Lithuania, cadastral surveys and juridical documents give ownership rights to property. While doing repeated surveys, enough big changes of land areas and cadastral data are observed. The average divergence does not exceed permissible error in the 75 % of analysed land plots and it makes 0.06 %. The primary data, on which base land plots were formed and legalized to ownership, should be specified to other 25 % land plots, which have 18.65 % error.

Šiame tyriamajame darbe išnagrinėjome, kokią įtaką detalės užlaidoms ir tarpiniams matmenims, turės detalės geometrinės ir kitos paklaidos. Kaip keisis minimalaus matmens išraiška po apdirbimo, kai detalės paviršius bus išgaubtas arba įgaubtas. Nustatėme minimalias užlaidas, esant bazinių paviršių ir apdirbamų paviršių tarpusavio padėties paklaidoms, taip pat įvertinome pjovimo įrankio dilimo ir temperatūrinių deformacinų įtaką. / The subject of the work: The influence of geometric and other errors for overlaps and idle measurement. The object of the research: The calculation of overlaps constituent and minimal idle measurement. The aim of the research was to revael the influence of the geometric and other errors for overlap details and idle measurements. What is the change of the aspect of minimal measurement after manufacturing when the surface of the detail is convex on concave. The research has defermined the minimal overlaps, when there are errors of the base and manufactured surface inter – position, also the influence of the cutter decrease and resilience was determined.

GENERAL CHARACTERISTIC OF THE DISSERTATION Topicality of the problem Prosthesis in orthopaedic technique are constructions that act as leg function reproduction and for external normal view of the leg. It is a technique giving a possibility to adapt to the society and live a full-fledged life, when one or another limb is lost. By the data, declared by the world health society, people with a disability include 10 % of all world population, among them people over 80 years old. More and more orthopaedic techniques are produced in Lithuania at present. The production, manufactured in our country keeps in step with world design and quality in foreign countries and they are 5–6 times cheaper. The main aim of the designers and constructors of orthopaedic techniques is to design and produce functional and high quality lower limbs prosthesis and apparatus. In the meantime, the same as abroad, in Lithuania the production processes of the prosthesis are automated but not so much to ensure a good quality of the prosthesis. Sometimes it is very hard to make prosthesis of adequate size to a patient that prosthesis implicitly fits just to the patient. Also, it is very hard to adjust it, ensuring the same length as the residual limb which should precisely correspond to the lost limb of the changeable loads chains of the prosthesis periodically are deformed during walking. In other words, the length of the prosthesis changes during gait. Thus, it is very important to set the limits of... [to full text]

Vibracijų diagnostika yra pagrindinis metodas, naudojamas įrenginių parametrų stebėjimui, kadangi būtent ši priemonė padeda nustatyti ir įvertinti mechaniniuose įrenginiuose kylančias problemas bei gedimus. Dirbančio pramoninio įrenginio su besisukančiomis dalimis vibracijų lygis yra vienas iš patikimiausių jų mechaninės būklės, surinkimo ir reguliavimo kokybės požymių. Maksimalių leidžiamų eksploatacinių vibracijų lygių nustatymas ir nuolatinė automatinė jų kontrolė leidžia padidinti įrenginių darbo patikimumą, jų aptarnavimo saugumą, sumažinti avarinių prastovų laiką ir sugadintų mechaninių dalių nuostolius. / Vibration refers to mechanical oscillations about an equilibrium point. The oscillations may be periodic such as the motion of a pendulum or random such as the movement of a tire on a gravel road. Vibration is occasionally "desirable". For example the motion of a tuning fork, the reed in a woodwind instrument or harmonica, or the cone of a loudspeaker is desirable vibration, necessary for the correct functioning of the various devices. More often, vibration is undesirable, wasting energy and creating unwanted sound – noise. For example, the vibrational motions of engines, electric motors, or any mechanical device in operation are typically unwanted. Such vibrations can be caused by imbalances in the rotating parts, uneven friction, the meshing of gear teeth, etc. Careful designs usually minimize unwanted vibrations.

Darbo objektas - Telšių miškų urėdijos, Žarėnų girininkijos brandūs mišrūs eglės su lapuočiais medynai. Darbo tikslas – nustatyti dažniausiai miško inventorizacijos praktikoje naudojamų tūrio nustatymo metodų tikslumą ir išanalizuoti jį lemiančias priežastis. Darbo metodai – tūrio paklaidų, gautų lyginant medienos tūrius, nustatytus pagal sklypinės miškų inventorizacijos ir biržių atrėžimo ir įvertinimo duomenimis su pagamintos medienos duomenimis, analizė. Darbo rezultatai. Atlikus tų pačių medynų tūrio įvertinimą įvairiais metodais ir visų matavimo rezultatų analizę, paaiškėjo, kad sklypinė miškų inventorizacija tūrį Žarėnų miško masyve vidutiniškai didina 10,2 %, lyginant su ištisiniu medžių apmatavimo metodu. Įvertinę brandžių medynų tūrį, pagal pagamintą medienos produkciją, gauti rezultatai mišriuose eglės medynuose svyruoja nuo -3,0 % iki 9,9 %, bendra paklaida yra 4,9 % didesnė lyginant su ištisiniu medžių matavimo metodu. Raktažodžiai: Sklypinė miškų inventorizacija, ištisinis medžių matavimas, atrankinis medžių matavimas, medynų tūris, paklaidos. / OBJECT OF RESEARCH-mature mixed spruce - broadlives forests in Telšiai forest enterprise, Žarėnai forest. AIM OF RESEARCH- to determine the accuracy of most frequently applied methods to rate the volume in the practice of forest inventory and to analyze the causes that influence it. METHODS OF RESEARCH- the analysis of volume errors, got by comparing timber volumes, set according to the data of inventory of forest plots and their delimitation and the data of their evaluation with the data of manufactured timber acceptance. RESULTS OF RESEARCH-after having done the evaluation of the same timber volume using different methods and the analysis of all the results of measurement, it emerged that stand-wise forest inventory increases the volume in the array of Žarėnai forests by 10.2% when compared to the continuous forest measurement. After evaluating the volume of mature trees according to the made timber production the results in mixed fir trees range from -3,0 % to 9,9 %, a common error 4,9 % better compared to the continuous forest measurement.

In this paper the problems of finding error estimates of quadrature formulas are discussed. A method proposed by K.Plukas was tested. One of the most important tests was the one determining the error estimates that are too optimistic. The results have shown that there are 1/8 of such error estimates and that there is no visible pattern when they occur. The second very important test was the one that shows how many iterations are needed to get the estimate of integral. After comparing the results to the ones produced by method of T.O.Espelid it was obvious that method of K.Plukas produced results even when method of T.O.Espelid was not able to. Comparison of these results have also shown that method of K.Plukas is not always as effective as method of T.O.Coteda, i.e. in many cases method of K.Plukas produced the result after more iterations than method of T.O.Coteda.

Research report on the reliability of results of Lithuanian forest inventories is given in the thesis. Aim of research – to estimate the reliability of the results of National forest inventory, Stand-wise forest inventory and forest inventory before cutting. Object of research – spruce and birch stands of Lithuanian forests. Methods of research – sampling, verification of statistical hypotheses and comparison of averages. Results of research – the reliability analysis of the results of National forest inventory shows, that calculated differences are statistically inconsequential. The reliability analysis of the results of Stand-wise forest inventory shows, that Stand-wise forest inventory results has allowed errors, except the height. The estimation of the reliability of results of forest inventory before cutting demonstrates that the errors are too high and the inequality of total volume of stands is -11,1 %.