bluuebunny/crossref_metadata_2025 huggingface dataset:
Prehydrating High-strength Microspheres in Lightweight Cement Slurry Creates Value for Offshore Malaysian Operator
Authors: Abdullah Mohd Nordin , Bedford David , Wong Suei Ru , Yap Hui San
Published: October 2013

Casing cementation across depleted reservoirs can be challenging because conventionally weighted cement slurries can induce losses and damage the permeability of formations caused by the higher associated hydrostatic pressure they exert on the wellbore. Therefore, when such pressure-related concerns exist, lighter-weight cement slurries are often preferred. For an offshore Malaysia operator, a lightweight cement slurry was proposed to reduce hydrostatic pressure and prevent losses and formation damage. However, instead of a water-extended lightweight cement slurry, a high-performance, lightweight (HPLW) cement slurry consisting of high-strength, hollow microspheres was designed.

Special bulk blending and transportation are normally required for these HPLW slurries because of the large bulk volume and low specific gravity (SG) of high-strength, hollow microspheres. In this case, because of limitations related to the rig’s storage capacity, the microspheres could not be stored conventionally and used as a dry additive to the slurry during mixing. Instead, an alternative solution involving prehydrating the high-strength microspheres with liquid additives and mix water in the mixing pits was implemented. This paper discusses the procedures used during cementing operations and details the value of using this mixing method.
Solving Hard/Abrasive Sedimentary and Igneous Formation Challenge: New PDC Bit Design Reduces 6-in Section Drilling Time By 47%
Authors: Peytchev Peter , Malik Sumit D. , Varghese Roy , Doodraj Sunil , Srinivasan Sudarsan , Benny Praveen , Raghav Sanjeev , Narayanan Shine
Published: October 2013

The 6"hole section in Raageshwari Field NW India (onshore) is typically between 600-800m long and highly challenging in terms of formation strength and abrasiveness. Lithology in the upper part is composed of sandstone, claystone and weathered basalt with unconfined compressive strength (UCS) between 3-5kpsi. The lower section contains basalt, felsic and sub-felsic igneous formations with UCS range of 15-30kpsi.

Historically, a two bit strategy was employed. First, a PDC bit on a positive displacement motor (PDM) bottom hole assembly was used to drill the soft 6" section until ROP dropped to an unacceptable level. The BHA was then pulled and followed by a diamond impregnated bit on a turbine BHA to drill the very hard volcanics. Typical average on-bottom ROP for the entire section was 4.5m/hr and took approximately 170 hours to reach total depth (TD).

To reduce costs, new technology was proposed to improve bit durability in the hard/abrasive volcanics and drill the entire 6" section in one run at a higher ROP. Recent bit and drilling data from offset wells was analyzed to assist in developing a new, cost effective PDC design to replace the expensive diamond-impregnated bits and drill the 6" hole section in one run. The study resulted in a new six-bladed PDC bit with 13mm cutters that incorporates superior cutter technology to improve durability and resist physical and thermal degradation. The design includes a row of backup cutters in the shoulder area to increase radial diamond volume for maximum durability.

The new PDC bits have been run on a motor and rotary steerable bottom hole assemblies and drilled the 6" section on three consecutive wells in Raageshwari field totaling 2328meters with an average ROP of 10.7m/hr. This represents approx. 47% decrease in drilling time compared to that previously achieved by Impreg/TCI bit runs. Typically, the new bits are pulled in re-runable condition. This improved performance has saved the operator approximately six-days of rig time and approximately USD 480,000/well.
An Improved Oil Recovery of Subsequent Water Flooding by Reuse of Residual Polymer in Reservoirs
Authors: Pei X. , Liang Y. , Zhou W. , Wang X. , Li G.
Published: October 2013

Satisfactory production increase and water-cut decrease has been achieved from polymer flooding in Daqing oil field, and the recovery increased by ten percentage points. However, significant residual oil and polymer solution still left behind polymer flooded reservoirs due to the effect of heterogeneity, so how to reuse the residual polymer solution prior to the subsequent water flooding is meaningful, which can both develop the remaining oil effectively and reduce the cost of profile control remarkably. Under simulating the actual field injection rate, this paper for the first time studied the presence form and residual amount of polymer solution in polymer-flooded cores, with permeability variation factors of 0.6-0.7. Then through analysis of residual polymer distribution and subsequent water breakthrough characteristics, cationic polymer particles were injected to react with the residual polymer for profile control, experimental results show the subsequent waterflood recovery increased more than 10 per cent. Field application indicates the injectivity of high-permeability profile modified intervals was limited, the injection profile has been improved effectively, and water cut of the central producers was reduced by 4.45 per cent. Polymer flooding has ended in more and more Chinese oil fields, this technique can be used as an effective means to further improve the oil recovery of subsequent water flooding in these fields.
VSP Surveys Aid Interpretation by Imaging Layers Not Visible in the Surface Seismic: Two Case Histories in Indonesia
Authors: Human Tertius , Muchtar Aldrin , Kunaifi Sunawar , Giyatno Seno
Published: October 2013

Genting Oil Kasuri Pte. Ltd. is operating in the Kasuri field in West Papua, Indonesia which is predominantly a gas field. Surface seismic was acquired over this area, followed by processing and interpretation. The drilling campaign ensued shortly afterwards and during drilling of the initial wells, a number of anomalies were encountered. It appeared that there were more layers present in the subsurface than were initially visible and interpreted from the surface seismic. A strong reflector at the Kais Limestone boundary may have caused reflections from deeper layers to be masked and not clearly visible on the surface seismic.

To get a clearer image and better understanding of the subsurface image, a number of VSPs were conducted. This paper shows two case studies and discusses the VSPs and results obtained in wells which are referred to here as Well-1 and Well-2.
Multistage Fracturing Proves Oil Potential in Low-Permeability Reservoirs in Thailand’s S1 Basin
Authors: Toempromaraj Wararrit , Sethavanish Somporn , Sompopsart Suwin , Vattanapornpirom Kanda , Anaskin Alexey , Wattanasuwankorn Reawat
Published: October 2013

Low-permeability sandstone formations in a deviated well were drilled and completed in 2010 by an oil company in Thailand. Openhole logging data and reservoir simulation modeling of multiple zones showed that the well would not produce because of tight formations. Artificial lifting calculations showed that the well was not likely to achieve hydrocarbon production targets for this well in its current condition. Multistage hydraulic fracturing was then considered for the well, and a plan was adopted to use this method to improve the well’s production while using reservoir simulations to optimize the fracture design. These methods were meshed with the completion and cleanout strategies to improve the well’s performance. The fracturing design was incorporated into a complete operational procedure, along with contingency plans, a decision tree, and an integrated communications plan to allow for any eventuality.

The careful planning resulted in the first successful multistage hydraulic fracturing operation in a deviated well in Thailand. The success resulted from careful planning, fluid testing, and a completion design that was fit-for-purpose, in conjunction with the well testing, to provide an excellent operational stimulation plan and execution.

Better-than-expected production from the well demonstrates that multistage fracturing in a deviated well in north Thailand can be successful and that this is a viable method for enhanced oil recovery (EOR) and improved well economics. This paper presents the well production results and operational procedures used to demonstrate that multistage fracturing is a viable method of completion in Thailand. Pressure matching and leakoff information gained from this operation will be of value in future fracturing operations to help improve those treatment designs
Introducing Integrated Surface & Subsurface Sand Management Systems for Rigless Interventions in East Malaysia
Authors: Zaki Zaini M. , Gornescu Bogdan C. , Saebi Shahryar , Whitney Patricio A. , Veysalli Elshan
Published: October 2013

One of the main challenges in the well intervention in offshore brown fields prone to sand production is both subsurface sand handling and also surface sand handling during the flow back and well cleaning. The field of interest is located offshore in East Malaysia. The field had been producing for almost three decades and is prone to sand production with no capabilities of surface sand handling.

This paper describes the integrated solution to address sand production on both surface and subsurface, targeting sand production from the unconsolidated reservoirs but also from well clean up before and after well intervention. In order to provide a cost effective solution for the new potential layer below the existing gravel pack zone, through tubing gravel pack technique was chosen as the sand control technique. This enabled the new zone to be produced in the optimum draw down without the risk of having sand production at surface. However prior to that, the rathole for the potential new layer had to be cleaned up using coil tubing. The sand and debris from this cleanout had to be circulated out to surface and needed to be separated before being disposed properly onshore. A cyclonic desander was temporarily installed on surface to achieve this. As a result, the integrated system provided overall solutions where downhole sand control was achieved and the cleanout fluid was free from solids to ensure no cascaded damages to the existing process facilities.

The system permitted to execute two wells cleanups, one through tubing gravel pack while complying with the very strict sand content limitations – particle size less than 45 microns and not more than 15pptb. The newly introduced technologies proved to be fit-for-purpose and robust, complying with sand content limitation as well as with all the other constrains.

The General description in term of operations and installation of such system as well as lessons learned and recommendations have been outlined in the paper that can be used as a reference for similar applications in the near future.
3D Sesimic Reprocessing for Geophysical Analysis of Sea Bottom, Seabed Mapping and Geohazard Clarification
Authors: Coral Juan Carlos , Paone Francesco , Marceglia Andrea
Published: October 2013

This paper presents a case study from the ENI operated Muara Bakau PSC (Jangkrik) on the East Kalimantan shelf edge and the west slope of the Makassar straits. The paper discusses the resolution and accuracy of Short-Offset Processed 3D Seismic Data (SOPS) and the applicability of the resulting Digital Terrain Models (DTM) for seabed mapping and initial field development planning.

For this case study a SOPS DTM of 12.5x12.5m grid spacing was generated covering a total area of 330 Km². A somewhat smaller area was later surveyed utilising an Autonomous Underwater Vehicle (AUV). The resulting AUV DTM was of 1x1m grid spacing. A number of exploration wells were already drilled within the area and accurate water depth measurements were performed from three of those wells. This provided the opportunity to evaluate the SOPS DTM accuracy and resolution. The results of the evaluation are presented in this paper. In the Jangkrik Project development, the SOPS DTM execution at early stage (during Concept Selection) allowed to:

Progress the subsea system design of a "fast track" project without waiting for site geophysical survey (AUV) Make key decisions at early stage avoiding the cost and time impact of later changes such as: One well (JK 7) was relocated because initially positioned within a canyon
Sensitive Area Mapping; The Important Step in Establishing the Oil Spill Response Strategy for Offshore Operations
Authors: Adi I. D. , Damar A.
Published: October 2013

Fast, accurate and immediate response is required in case of oil spill occured from the offshore oil and gas activities to minimize the impact to the environment and prevent from the bad reputations. The response strategy should consider the resources availibility and sea condition uncertainity. Every area that may experienced oil spill in the sea should have a map of priority area to be protected. Furthermore this map should be updated in certain period of time incorporated satellite image analysis, field data measurement and validation, as well as Environmental Sensitivity Indices (ESI). ESI was determined based on 3 variables namely vulnerability, ecologies, and socio-economics. The results will be categorized as very sensitive, sensitive, moderate, less sensitive and not sensitive. The study area are in the south eastern coast of Lampung in Sumatra Island until along the north western coast of Java islands, in the area of latitude between 040,24’25.50"S and 06010’45.57"S and meridien between 105045’4.11"E and 107049’81"E South East Sumatera. Since the study area is very huge, it is divided into 3 divisions and each division consisted of 16 units of analysis. The sensitivity area mapping shows that the most sensitive area for division 1 is the locations surrounding Way Kambas National Park, while in the division 2 is the location surrounding Jakarta Bay and all areas in the division 3 which is Kepulauan Seribu. Sea condition uncertainity is represented on oil spill simulation using OSIS (Oil Spill Information Systems) software. The results shows that the most likely impacted area when the oil spill occurs in the sea lane and in the oil companies activities are Kepulauan Seribu in Division 3 with the probability of 83%, Jakarta Bay in Division 2 with the probability of 75%. Meanwhile, the probability of East Lampung Coast in Division 1 is 0%. Application of ESI combined with oil spill dispersion model is a robust method in defining the most effective strategy in combating strategy of oil spill. This method can be applied in determining the priority ranks of action in protecting the shoreline impacted by the oil spill.
Pipeline Integrity Management System in South East Sumatra Offshore
Authors: Habil Mohammad
Published: October 2013

Many current oil fields in the world were developed several decades years ago that have the facilities more that 30 – 40 service years or already over the design live. Consequently this requires some effort to ensure that the integrity of all facilities is still acceptable. These facilities are including pipelines to deliver hydro carbon which may be laid at onshore or offshore. South East Sumatra block is as an offshore operation operates more than 800 KM long covering 136 pipelines, in which more than 50% of them had over the design life. Various diameter of pipelines are installed between 4" – 22" and delivering of trace oil, multi phase fluids, produced water, sea water, wet and dry gas. PIMS was introduced since three years ago in order to identify the integrity of pipelines, the risk, probability of failure, consequent of failure, remaining maximum operating pressure, reasonable and efficient inspection, monitoring to be proceeded, proper maintenance and adequate repair to be executed. Also avoid any pollution on environment, especially at the Thousand Island Under Water Park, Jakarta which is about 50 KM from the South East Sumatra oil and gas fields.
Repeat Dynamic Underbalance Perforating in Oman
Authors: Jumaat Mohd Shafie
Published: October 2013

Dynamic underbalance (DUB) is a technique that has been used for many years by many operators to deliver cleaner perforation tunnels so as to achieve better well productivity or injectivity. Its advantage is shown in the laboratory and by many field jobs. Unlike conventional static underbalance perforating, the DUB perforating technique delivers a sharp pressure drop at the time of perforating, which is critical in breaking down the low-permeability zone around the perforation tunnel, commonly known as the crushed zone.

After several years of DUB application in the industry, the technique evolved into the DUB post-perforating technique in which a gun chamber is instantaneously opened at the existing perforations to create a sharp pressure drop to clean the crushed zone. This technique has been successfully applied in both the laboratory and in the field.

Other laboratory work has provided greater insight into the nature of perforating tunnel damage and how effective the standard DUB or post-perforating DUB technique can be in cleaning them. From this understanding and implementation of both DUB techniques, the repeat-DUB technique is proposed.

The repeat-DUB technique delivers perforations by the standard DUB technique and subsequently treats them with the DUB post-perforating technique, all in the same job. Although the DUB techniques produce perforations with a good productivity index (PI), the repeat DUB sequence further enhances the PI. This paper discusses the concepts and why and where this technique enhances the PI, including a review of, the basics of the DUB technique in comparison with various surging techniques. The repeat-DUB technique has been applied to 35 wells in a field in Oman with good results.
Aceh Operations Mature Field Management: Arun Assets Consolidation and North Sumatera Offshore (NSO) Liquid Handling
Authors: Avida Hanifatu , Soedarmo Auzan A , Utama Dheli P
Published: October 2013

This paper describes integrated asset management team efforts to sustain safe and profitable production of mature fields. Two case studies are presented: Excess assets consolidation at the onshore Arun field in Aceh province, and reservoir liquid breakthrough handling at the North Sumatera Offshore (NSO) field.

The Arun field has been producing since 1977. Currently more than 99% of expected ultimate gas recovery has been produced. Surface facilities were designed for a peak capacity of 3,500 MMSCFD with multiple well clusters and production trains. With production declining to less than 5% of design capacity, the majority of facilities have significant excess capacity. Asset consolidation efforts were started in 2004 with the Arun Cluster Consolidation Project (ACCP) to centralize gas dehydration and booster compression facilities into one cluster. In total, ACCP reduced active assets by 60%, operating expense by $350K annually, and fuel gas consumption by 9 MMSCFD. The ACCP was followed by the Liquid Handling Project (LHP) to consolidate liquid separation and transfer facilities from four clusters into two. Completed in 2010, the LHP reduced manpower by ~ 600 man-hours per year and avoided machinery reliability issues due to operation below turndown limit.

Liquid handling is often a major bottleneck for offshore gas facilities, especially after formation water breakthrough on platforms that treat and discharge produced water overboard. Weight and footprint limitations restrict flexibility for de- bottlenecking. The NSO platform was designed with a total liquid handling capacity of 2,500 BPD, subject to a regulatory overboard water quality limit of 50 ppm oil in water content. Improvements in the chemical treatment and physical separation processes were utilized to increase capacity by 40 percent to 3,500 BPD while continuing to meet condensate quality and overboard water targets, enabling production to be maximized in spite of increasing water breakthrough.
New 9-aminoacridine derivatives as inhibitors of Botulinum neurotoxins and P. falciparum malaria
Authors: Tot Miklos , Opsenica Dejan , Mitric Milena , Burnett James , Gomba Laura , Bavari Sina , Solaja Bogdan
Published: October 2013

Steroidal and adamantane aminoacridine derivatives were prepared and tested
as both botulinum neurotoxin (BoNT) inhibitors and antimalarials.
Steroid-bound acridines provided good potency against both the BoNT/A and
BoNT/B light chains (LCs). The observed inhibition of the BoNT/B LC by ca.
50% is the highest attained inhibitory activity against this serotype by
acridine-based compounds to date. With respect to antimalarial activity,
adamantane acridines were the most potent derivatives (IC50 = 6-9 nM, SI >
326), indicating that an adamantyl group is a better carries than a steroidal
motif for this indication.
Assessment of the Effect of Casein Phosphopeptide–amorphous Calcium Phosphate on Postoperative Sensitivity Associated With In-office Vital Tooth Whitening
Authors: Maghaireh GA , Alzraikat H , Guidoum A
Published: October 2013

The aim of this study was to evaluate the efficacy of tooth mousse containing 10% casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) in reducing tooth sensitivity associated with in-office vital tooth whitening. In-office tooth whitening was performed for 51 participants using 35% hydrogen peroxide gel in a single visit. After the procedure, each participant was randomly assigned to one of three groups: gel without desensitizing agent (n=17), gel with 2% sodium fluoride (n=17), gel with 10% CPP-ACP (n=17). A small amount of the desensitizing gel assigned for each participant was applied directly on the labial surfaces of teeth and left undisturbed for three minutes. The participants were asked to apply the gel assigned to them for three minutes twice daily after brushing their teeth, and to continue this for 14 days. The participants were asked to return for follow-up visits after 24 hours and on days 3, 7, and 14, at which time teeth shade changes were assessed by one evaluator using a value-oriented Vita classic shade guide. The incidence, duration, and intensity of tooth sensitivity experienced was self-assessed on a daily basis for the 14-day study period using a visual analog scale (VAS). The effect of the three gels on tooth sensitivity was assessed using one-way analysis of variance and a χ2 test (α=0.05). The general linear model was used to compare intensity-level differences in the three studied groups and for shade stability over the follow-up period. The results of this study showed that all three gels decreased the intensity of sensitivity associated with tooth whitening. The intensity of sensitivity was lower in the fluoride group than in the other two groups; however, it was not statistically significant (p=0.112 and p=0.532 on day 1 and day 2, respectively). The average shade change was 6.8. None of the tested materials affected the efficacy of tooth whitening, but the shade change among the fluoride group showed more color stability than that of the other two groups. This study suggested that using a gel after tooth whitening can reduce the intensity of tooth sensitivity associated with in-office whitening procedures without affecting the efficiency of tooth whitening. However, it failed to demonstrate that using a 10% CPP-ACP could provide additional therapeutic benefits.
Evaluation of Color Changes in the Vitapan Classical Shade Guide After Disinfection
Authors: Alshethri SE
Published: October 2013

The purpose of this study was to evaluate how one, two, and three years of simulated treatments affect the colors of Vitapan Classical Shade Guide tabs after being chemically disinfected. Ten shade tabs (one, control; nine, disinfection) were evaluated visually and by chromameter for color changes after disinfection. Results showed that 0.62 ΔE was found after three years of disinfection. The color changes in the shade guide tabs were perceptible or noticeable to the human eye in eight out of 45 shade tabs (17.8%) after two years and in 13 out of 45 shade tabs (28.9%) after three years of treatment. It was concluded that one shade guide should be retained as a control and periodically compared with the shade guide in use to determine when the shade tabs in use should be replaced or discarded.
Surface relief grating formation in luminescent dye doped photochromic polymer containing azobenzene side groups
Authors: Sznitko Lech , Karpinski Pawel , Bartkiewicz Stanislaw , Miniewicz Andrzej , Mysliwiec Jaroslaw
Published: October 2013

We study the formation of a surface relief grating and photoluminescence in a thin layers of a photochromic polymer doped with the luminescent dyes 3-(1,1-dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole and Rhodamine 6G. Surface topography measurements via Atomic Force Microscopy confirmed the existence of a surface relief grating with amplitudes as high as 650 nm both for doped and undoped photochromic polymers. Spectroscopic measurements carried out for polymers containing luminescent dyes have shown efficient photoluminescence and amplified spontaneous emission which is characteristic for gain media.
Genitourinary Small-Cell Carcinoma: A Single-Institution Experience
Authors: Pervez N. , El-Gehani F. , Joseph K. , Dechaphunkul A. , Kamal M. , Pertschy D. , Venner P. , Ghosh S. , North S.
Published: October 2013

Background: Small-cell carcinomas (sccs) of the genitourinary (gu) tract are rare systemic diseases, and there is no standard treatment strategy for patients with this malignancy. The objectives of the present study were to report the management and outcome of patients with scc of the gu tract treated at a tertiary-care institution from 1982 to 2009. Methods: In a chart review of all patients diagnosed with scc of the gu tract between 1982 and 2009, data on demographics, clinical and pathologic characteristics, treatment, and patient outcomes were collected. Results: The 58 patients identified had scc in the following primary sites: urinary bladder (n = 35), prostate (n = 17), and upper urinary tract (n = 6). In 38 patients (66%), the scc was of pure histology; in the remainder, histology was mixed. Overall, 28 patients had limited-stage disease; 24 had extensive-stage disease; and staging was unknown in 6 patients. Median survival for the entire cohort was 7.5 months, with extensive-stage disease being identified as a poor prognostic factor (survival was 22.0 months for limited-stage patients and 4.1 months for extensive-stage patients, p < 0.001). Based on site, prostate patients fared worst, with a median survival of only 5.1 months. Compared with best supportive care, treatment was associated with better outcomes (median survival: 12.3 months vs. 2.3 months, p < 0.0001). Conclusions: Small-cell cancer of the gu tract is an aggressive cancer, with a poor prognosis overall. Although there is no standard of care, patients should be treated using a multimodality approach analogous to that used in the treatment of small-cell lung cancer.
IMAGE FILTERING WITH FIELD PROGRAMMABLE GATE ARRAY / VAIZDŲ FILTRAVIMAS LAUKU PROGRAMUOJAMA LOGINE MATRICA
Authors: Šlenderis Arūnas , Daunys Gintautas
Published: October 2013

The research examined the use of field programmable gate arrays (FPGA) in image filtering. Experimental and theoretical researches were reviewed. Experiments with Cyclone III family FPGA chip with implemented NIOS II soft processor were considered. Image filtering was achieved with symmetrical and asymmetrical finite impulse response filters with convolution kernel. The system, which was implemented with 3×3 symmetrical filter, which was implemented using the hardware description language, uses 59% of logic elements of the chip and 10 multiplication elements. The system with asymmetrical filter uses the same amount of logic elements and 13 multiplication elements. Both filter systems consume approx. 545 mW of power. The system, which is designed for filter implementation in C language, uses 65% of all logical elements and consumes 729 mW of power.

Article in Lithuanian.

Santrauka

Nagrinėjama, kaip vaizdams filtruoti naudojamos lauku programuojamos loginės matricos (LPLM). Apžvelgti eksperimentiniai ir teoriniai darbai. Atlikti bandymai su Cyclone III šeimos LPLM lustu, kuriame buvo įdiegtas įkeliamasis NIOS II procesorius. Vaizdai filtruoti su simetriniu ir nesimetriniu ribotos impulsinės reakcijos filtrais, naudojant sąsūkos branduolį. Sistema, kuri buvo įdiegta kartu su 3×3 simetriniu filtru, naudojant aparatinės įrangos aprašymo kalbą, naudoja 59 % lusto loginių elementų ir 10 dauginimo elementų. Ši sistema su nesimetriniu filtru naudoja tiek pat loginių elementų ir 13 dauginimo elementų. Abiejų filtrų sistemų naudojama galia yra panaši – apie 545 mW. Sistemos su įkeliamuoju procesoriumi naudojamų loginių elementų dalis siekia 65 %, naudojama galia – 729 mW.
MODIFIED SURF ALGORITHM IMPLEMENTATION ON FPGA FOR REAL-TIME OBJECT TRACKING / MODIFIKUOTO POŽYMIŲ VAIZDE IŠSKYRIMO SURF ALGORITMO OBJEKTUI SEKTI REALIUOJU LAIKU ĮGYVENDINIMAS LAUKU PROGRAMUOJAMOJE LOGINĖJE MATRICOJE
Authors: Sledevič Tomyslav
Published: October 2013

The paper describes the FPGA-based implementation of the modified speeded-up robust features (SURF) algorithm. FPGA was selected for parallel process implementation using VHDL to ensure features extraction in real-time. A sliding 84×84 size window was used to store integral pixels and accelerate Hessian determinant calculation, orientation assignment and descriptor estimation. The local extreme searching was used to find point of interest in 8 scales. The simplified descriptor and orientation vector were calculated in parallel in 6 scales. The algorithm was investigated by tracking marker and drawing a plane or cube. All parts of algorithm worked on 25 MHz clock. The video stream was generated using 60 fps and 640×480 pixel camera.

Article in Lithuanian

Santrauka

Pateikiamas modifikuoto požymių vaizde išskyrimo algoritmo SURF įgyvendinimas lauku programuojamų loginių matricų (LPLM) įrenginiuose. LPLM įrenginiai pasirinkti dėl galimybės tuo pat metu įgyvendinti veikiančius procesus taikant VHDL kalbą. Tai garantuoja, kad požymiai vaizde bus išskirti realiuoju laiku. Skaičiavimams paspartinti taikomas slankusis 84×84 taškų dydžio langas, kuriame saugomas sudėtingas vaizdas. Šio slankiojo lango duomenys taikomi Hessian determinantui, būdingųjų taškų orientacijai ir deskriptoriams apskaičiuoti. Požymiai ieškomi aštuoniose skalėse taikant lokalių ekstremumų paiešką. Požymių orientacijos vektorius ir supaprastintas deskriptorius skaičiuojami šešiose skalėse tuo pat metu. Algoritmo veikimas tiriamas sekant keturių taškų žymeklį ir pagal jį braižant plokštumą arba erdvinį kubą. Skaičiuojama 25 MHz taktiniu dažniu. Vaizdui gauti taikoma 60 kadrų per sekundę dažnio 640×480 taškų raiškos vaizdo kamera.
THE EFFICIENCY ANALYSIS OF THE AUGMENTED REALITY ALGORITHM / PAPILDYTOS REALYBĖS ALGORITMO EFEKTYVUMO TYRIMAS
Authors: Kurpytė Dovilė
Published: October 2013

The article presents the investigation of the efficiency of augmented reality algorithm that depends on the rotation angles and lighting conditions. The following were the target subject parameters: three degrees of freedom perspective of the rotation and side lighting that forms a shadow. Static parameters of subjects with the ability to change them were as follow: the distance between the marker and the camera, camera, processor, and the distance from the light source. The study is based on an open source Java programming language algorithm, where the algorithm is tested with 10 markers. It was found that the rotation error did not exceed 2%.

Article in Lithuanian

Santrauka

Straipsnyje nagrinėjamas papildytos realybės (PR) algoritmo efektyvumas keičiant posūkio kampus ir apšvietimą. Tiksliniai keičiami tiriamieji parametrai yra šie: trijų laisvės laipsnių atžvilgiu nagrinėjama posūkio kampo įtaka ir šoninis apšvietimas, sudarantis šešėlį. Statiniai tiriamieji parametrai su galimybe juos pakeisti yra šie: atstumas tarp žymeklio ir kameros, kamera, procesorius, atstumas iki šviesos šaltinio. Ištyrus atvirojo kodo Java programavimo kalba įgyvendintą algoritmą su dešimčia skirtingų žymeklių, pateikiamos rekomendacijos.
COMPARISON OF THE REST ARCHITECTURAL STYLE WITH SOAP IN IMPLEMENTATION OF MODERN WEB SERVICES / REST ARCHITEKTŪRINIO STILIAUS PALYGINIMAS SU SOAP, ĮGYVENDINANT ŠIUOLAIKINES INTERNETO PASLAUGAS
Authors: Stankevičius Kęstutis
Published: October 2013

One of the most relevant steps in the development of an information system during implementation of web services is moving the existing program functionality onto the web. Although web services have been advancing together with software, implementation requires special attention. Accessible options allow organisations to search for alternatives that would suit their needs, i.e. would be cheaper and more effective as well as possibly easier and faster to implement. The paper aims to compare a standard method for creation of web services with another architectural style for implementation of web services, which is getting more widely used.

Article in Lithuanian

Santrauka

Interneto paslaugų įgyvendinimas, siekiant perkelti programų funkcionalumą į interneto paslaugų sąsają, yra vienas aktualiausių informacinės sistemos kūrimo etapų. Interneto paslaugos tapo neatsiejama programinės įrangos dalimi, bet blogi paslauginių architektūrų įgyvendinimo rezultatai verčia susimąstyti. Informacinių sistemų pardavėjams palankios specifikacijos verčia įmones ieškoti alternatyvų, patenkinančių jų nustatytus poreikius, t. y. pigesnių, efektyvesnių ir galbūt greičiau įgyvendinamų. Straipsnyje bandoma palyginti standartinį būdą teikti interneto paslaugas su kitu architektūriniu interneto paslaugų įgyvendinimo stiliumi. Pastarasis vis plačiau taikomas jau nuo 2008 m.
FPGA-BASED IMPLEMENTATION OF LITHUANIAN ISOLATED WORD RECOGNITION ALGORITHM / LIETUVIŲ KALBOS PAVIENIŲ ŽODŽIŲ ATPAŽINIMO ALGORITMO ĮGYVENDINIMAS LAUKU PROGRAMUOJAMA LOGINE MATRICA
Authors: Sledevič Tomyslav , Stašionis Liudas
Published: October 2013

The paper describes the FPGA-based implementation of Lithuanian isolated word recognition algorithm. FPGA is selected for parallel process implementation using VHDL to ensure fast signal processing at low rate clock signal. Cepstrum analysis was applied to features extraction in voice. The dynamic time warping algorithm was used to compare the vectors of cepstrum coefficients. A library of 100 words features was created and stored in the internal FPGA BRAM memory. Experimental testing with speaker dependent records demonstrated the recognition rate of 94%. The recognition rate of 58% was achieved for speaker-independent records. Calculation of cepstrum coefficients lasted for 8.52 ms at 50 MHz clock, while 100 DTWs took 66.56 ms at 25 MHz clock.

Article in Lithuanian.

Santrauka

Pateikiamas lietuvių kalbos pavienių žodžių atpažinimo algoritmo įgyvendinimas lauku programuojama logine matrica (LPLM). LPLM įrenginys pasirinktas dėl lygiagrečiai veikiančių procesų įgyvendinimo galimybės taikant VHDL kalbą. Tai užtikrina spartų signalų apdorojimą esant taktiniam dažniui iki 50 MHz. Kalbos požymiams išskirti taikoma kepstrinė šnekos analizė. Požymiams palyginti taikomas dinaminis laiko skalės kraipymo (DSLK) metodas. Sudaryta 100 žodžių požymių biblioteka, kuri saugoma vidinėje LPLM BRAM atmintyje. Pasiektas 94 % atpažinimo tikslumas priklausomai nuo kalbėtojo ir 58 % – nepriklausomai nuo kalbėtojo. Kepstro koeficientų skaičiavimas vienam žodžiui trunka 8,52 ms, esant 50 MHz taktiniam dažniui, ir šimtui DLSK – 66,56 ms, esant 25 MHz taktiniam dažniui.
ENERGY DETECTOR IMPLEMENTATON IN FPGA FOR ESTIMATION OF WORD BOUNDARIES / ENERGIJOS DETEKTORIAUS, NAUDOJAMO ŽODŽIO RIBOMS NUSTATYTI, ĮGYVENDINIMAS LAUKU PROGRAMUOJAMA LOGINE MATRICA
Authors: Stašionis Liudas , Sledevič Tomyslav
Published: October 2013

This paper describes implementation of the word boundary estimation module in FPGA. The boundary estimation module is based on energy detector. This module is optimized for implementation in FPGA. It occupies 54 logical elements “Slice” and uses only 0.7% of “Spartan-6 LX45” resources. Experiments with this module were performed at different signal/noise (S/N) ratio. For S/N of 20 dB and 15 dB word boundaries were estimated with 100% accuracy. Acceptable results were also achieved, for S/N ratio of 10 dB and 5 dB, as the estimation accuracy was 95% and 93%, respectively. Article in Lithuanian. Santrauka Pateikiamas žodžio ribų nustatymo modulio įgyvendinimas lauku programuojama logine matrica (LPLM). Žodžio riboms nustatyti pasirinktas energijos detektorius, nes šis metodas, naudojant skaitmenines signalų apdorojimo priemones, įgyvendinamas efektyviai. Žodžio ribų nustatymo modulis buvo optimizuotas tiek, kad, įgyvendintas LPLM, jis užėmė 54 loginius elementus „Slice“ – tik 0,7 % „Spartan-6 LX45“ lusto išteklių. Eksperimentuojant nustatyta, kad esant 20 dB ir 15 dB signalo triukšmo santykiui, žodžio ribos nustatomos tiksliai, o kai šis santykis yra 10 dB ir 5 dB, žodžio ribos nustatomos 95 % ir 93 % tikslumu.
SIMULATION OF FREQUENCY CONTROLLED ELECTRIC DRIVE USING SCALAR CONTROL METHOD / SKALIARINIU BŪDU VALDOMOS DAŽNINĖS ELEKTROS PAVAROS IMITACINIS TYRIMAS
Authors: Kriaučiūnas Jonas , Kerpė Laurynas
Published: October 2013

This paper presents scalar controlled induction motor model and analysis of dynamic characteristics. The paper considers the closed loop electric drive system with proportional-integral-derivative (PID) regulator. The model of AC drive is presented in synchronous reference frame. Simulation of the proposed system is considered with different speed reference and load signals, also with different PID regulator parameters (coefficients KP, KI, KD). The selected and tuned regulator significantly decreased speed transient time, and after loading restored it to the reference signal.

Article in Lithuanian.

Santrauka

Nagrinėjamas dažninės elektros pavaros, valdomos skaliariniu būdu, imitacinių modelių sudarymas ir dinaminių charakteristikų analizė. Sudarytas uždarosios elektros pavaros su proporciniu-integraliniu-diferencialiniu reguliatoriumi (PID) Simulink modelis. Variklio modelis sudarytas sinchroniniu greičiu besisukančioje koordinačių sistemoje. Išnagrinėti dažninės elektros pavaros pereinamieji vyksmai, esant skirtingiems greičio nuostatams, skirtingoms statinėms apkrovoms ir skirtingiems reguliatoriaus suderinimo koeficientams KP , KI , KD. Parinktas ir sukonfigūruotas reguliatorius labai sumažina variklio paleidimo trukmę bei, įjungus apkrovą, atkuria greitį į pradinę, iš anksto nustatytą vertę, lygią nuostatui.
THE RESEARCH OF THE BASIC CHANNEL CONTROL PROCESS OF PETROLEUM DISTILLATION AND DEVELOPMENT OF DYNAMIC MODELS / PAGRINDINIŲ NAFTOS DISTILIAVIMO SISTEMOS KANALŲ VALDYMO PROCESŲ TYRIMAS IR DINAMINIŲ MODELIŲ SUDARYMAS
Authors: Likhavitski Vitaliy
Published: October 2013

As the object of control, the process of oil distillation in the atmospheric column is complex and multidimensional with interconnected controlled variables. These controlled variables are the outgoing indexes of the column – the quality of receivable hydrocarbon fractions, for assessment of which the boiling point for each product is used. The basic perturbation actions to the process are connected with the adjustment of quantity and the composition of feed stock supplied to the column and flow heat transfer change due to temperature fluctuation of feed stock, temperature fluctuations of external reflux and other factors.

Santrauka

Atmosferinės naftos distiliavimo talpyklos sistemos valdymas yra sudėtingas ir daugiamatis procesas. Jį sudaro tarpusavio ryšiais susieti kintamieji. Tai yra distiliavimo talpyklos parametrai – gautųjų angliavandenilio frakcijų kokybė, pagal kurią nustatoma kiekvieno produkto virimo temperatūra. Šio proceso sudėtingumas siejasi su skysčio, tiekiamo į talpyklą, srauto ir sudėties reguliavimu, srauto temperatūros perdavimo pokyčiais dėl tiekiamo skysčio temperatūros bei atgalinio srauto temperatūros svyravimo ir kitų veiksnių.

Straipsnis anglų kalba.
OPERATIONALAMPLIFIER ANALYSIS WHEN MIGRATING FROM 0.18 ΜM TO 65 ΜM CMOS TECHNOLOGY / OPERACINIŲ STIPRINTUVŲ PARAMETRŲ TYRIMAS 0,18 ΜM IR 65 NM KMOP TECHNOLOGIJOSE
Authors: Kiela Karolis , Jurgo Marijan
Published: October 2013

The article offers the analysis of operational amplifier parameter changes, when circuits are scaled from 0.18 μm to 65 nm CMOS technology. Two two-stage operational amplifiers were designed for this purpose: first uses n-MOS input differential pair; second uses cascaded active loads structure and p-MOS type input differential pair. The operational amplifiers were designed in 0.18 μm CMOS technology and scaled to 65 nm CMOS. Other scaling methods were also analysed when redesigning circuits from one IC technology to another. Results of the original and scaled operational amplifier parameters are presented and analysed.

Article in Lithuanian.

Santrauka

Nagrinėjami pagrindiniai operacinių stiprintuvų parametrai, jų pokytis pereinant iš 0,18 μm į 65 nm KMOP technologiją. Tyrimui atlikti suprojektuoti ir panaudoti du skirtingi dviejų pakopų operaciniai stiprintuvai: pirmas su n-MOP tipo įėjimo diferencine pakopa; antras – su p-MOP tipo įėjimo diferencine pakopa ir kaskodine aktyviųjų apkrovų sandara. Operaciniai stiprintuvai projektuoti naudojant 0,18 μm KMOP procesą kaip pagrindinę technologiją ir vėliau, nustatant mastelį, perkelti į 65 nm KMOP technologiją. Kitos perkėlimo procedūros naudojamos pereinant iš vienos integrinės technologijos į kitą. Sumodeliuoti ir palyginti suprojektuotų operacinių stiprintuvų parametrai.
PROBLEMS OF USING FEMTOCELLS IN PUBLIC CELLULAR NETWORKS / FEMTOCELIŲ NAUDOJIMO PROBLEMATIKA MOBILIOJO RYŠIO TINKLUOSE
Authors: Žvinys Karolis
Published: October 2013

This paper analyses the use of femtocells connected into a single macro network infrastructure. Different problems and possible solutions were discussed. The paper is focused on two separate benefits, which HNB could bring an operator and user. Femtocells are especially appealing due to the freedom of installation, increased macro network capacity, femto zone rates and etc. They provide users with better service quality, including voice service and higher throughput; while operators can reduce their network deployment expenditures. On the other hand, unplanned deployment, mobility issues and different types of user groups can cause a headache both for operators and customers. The analysis demonstrated that the majority of features of femtocells from the operator’s point of view were positive. Looking from the user’s point of view, most of shortcomings are difficult to remove. Positive and negative features both for operators and clients are presented in the HNB model.

Article in Lithuanian.

Santrauka

Darbe nagrinėjami femtocelių naudojimo, jungiant jas į bendrą makrotinklo infrastruktūrą, klausimai. Analizuojami kylantys sunkumai ir jų sprendimo variantai. Išskiriamos dvi: vartotojų bei operatorių – šakos, kuriose analizuojama femtocelių teikiama nauda. Lengvas diegimas, tinklo talpumo didinimas, naujų femtozonų atsiradimas. Visa tai femtoceles daro patrauklias šiandieniam naudojimui tinkluose. Vartotojo požiūriu užtikrinama balso skambučių kokybė, didelis duomenų pralaidumas. Be to, operatorius turi galimybę plėsti tinklą daug mažesnėmis sąnaudomis. Neplanuoto diegimo principai, mobilumas, skirtingo tipo vartotojų grupės gali sukelti didelių sunkumų vartotojui naudojantis femtocele, o operatoriui užtikrinti tinkamą jų funkcionavimą. Atlikta femtocelių savybių analizė rodo, kad operatoriaus požiūriu didžioji dalis HNB savybių yra teigiamos. Iš kliento pozicijos pasireiškiantys trūkumai šalinami sunkiai. Teigiamų ir neigiamų savybių pasiskirstymas operatoriaus ir kliento šakoms pateikiamas HNB modeliu.
DOXORUBICIN-LOADED MICELLES OF Y-SHAPED PEG-(PCL)2AGAINST DRUG-RESISTANT BREAST CANCER CELLS
Authors: Cuong Nguyen-Van , Chen Yung-Tsung , Hsieh Ming-Fa
Published: October 2013

Y-shaped amphiphilic copolymers have been synthesized by various strategies. They can self-assemble to form stable micellar drug carriers. Higher ratio of hydrophobic segment in these micelles is known to stabilize encapsulated drugs. This study used methoxy poly(ethylene glycol) (mPEG, A block) and poly(ε-caprolactone) (PCL, B block) to synthesize an AB2type amphiphilic block copolymer to encapsulate the anticancer drug, doxorubicin (DOX). The synthesized mPEG-(PCL)2self-assembled into nanoparticles and its critical micelle concentration was 43.7 × 10-3mg/mL. The particle size of empty micelle and DOX-loaded micelle was 95.1 and 21.4 nm, respectively. DOX-loaded micelles have a drug- loading efficiency of 22.3% and could be released from micelles up to 50% at pH 5 and 40% at pH 7.4 in 48 h in an in vitro release experiment. The nitric oxide (NO) assay indicated that the micelles could avoid the cytotoxic recognition by murine macrophage cells. The half-lethal dose (IC50) of DOX-loaded micelles for two human breast cancer cell lines (MCF-7/WT for wild-type and MCF-7/ADR for adriamycin-resistant) were 0.937 and 7.476 μg/mL, respectively. For MCF-7/ADR cells, the ratio of IC50of free DOX vs. that of DOX-loaded micelles, which reported as resistance reversion index, was 0.125. Confocal images showed that DOX-loaded micelles accumulated mostly in the cytoplasm instead of nuclei. On the contrary, free DOX diffused throughout the cells. Flow cytometric histograms indicated that the fluorescence intensity in MCF-7/ADR cell line was about 83.2% and 50.9% for DOX-loaded micelles and free DOX, respectively. This result indicates that the DOX-loaded micelles formed by AB2copolymer could overcome multidrug resistance of breast cancer cells as it can accumulate more in MCF-7/ADR cells compared with free DOX.
HIGH GLUCOSE INDUCED BONE LOSS VIA ATTENUATING THE PROLIFERATION AND OSTEOBLASTOGENESIS AND ENHANCING ADIPOGENESIS OF BONE MARROW MESENCHYMAL STEM CELLS
Authors: Li Wen-Tyng , Hu Wen-Kai , Ho Feng-Ming
Published: October 2013

Diabetes mellitus (DM) is associated with bone loss and leads to osteopenia and osteoporosis. This study was undertaken to investigate whether the impaired functions of mesenchymal stem cells (MSCs) derived from bone marrow play a role in pathogenesis of DM-associated bone loss. Bone marrow MSCs were taken from the alloxan-induced diabetic rats and normal rats. Bone mineral densities of tibias and femurs in diabetic rats decreased compared to those of normal rats as shown by dual energy X-ray absorptiometry. MSCs from diabetic rats exhibited reduced colony formation activity. The in vitro effects of high glucose (HG) (20 or 33 mM) on the growth, oxidative stress, apoptosis, and differentiation MSCs were next assessed. The viability and proliferation of MSCs derived from diabetic rats decreased significantly compared with that from normal rats. HG further suppressed the proliferation and viability of MSCs from both diabetic and normal rats. HG was associated with 38–40% increase in reactive oxygen species level and had significantly downregulated the activities of superoxide dismutase (SOD) and catalase (CAT) which could be recovered by the addition of L-ascorbic acid. The phenomena of apoptosis such as chromatin condensation and DNA fragmentation were found in cells cultured under HG conditions. As compared with 5.5 mM glucose, exposure of MSCs to HG enhanced adipogenic induction of triacylglycerol accumulation and inhibited osteogenic induction of alkaline phosphatase activity. HG increased peroxisome proliferator-activated receptor gamma expression during adipogenesis and reduced RUNX2 expression during osteoblastogenesis. These results indicate that MSCs derived from diabetic rats exhibited the inhibitory effects on cell growth and osteogenic ability. The oxidative stress, apoptosis, and adipogenic capability of MSCs were increased by HG. Furthermore, it is suggested that HG induces bone loss via attenuating the proliferation and osteoblastogenesis and enhancing adipogenesis mediated by the oxidative stress in rat bone marrow MSCs.