bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing a Measurement for Task Complexity in Flight
Authors: Zheng Yiyuan , Lu Yanyu , Wang Zhen , Huang Dan , Fu Shan
Published: July 2015

INTRODUCTION: Task complexity is regarded as an essential metric that is related to a pilot’s performance and workload. Normally, pilots follow Standard Operating Procedures (SOPs) during a flight. In this study, we developed a measurement named Task Complexity in Flight
(TCIF) to represent the task complexity in the SOPs.METHODS: The TCIF measurement combined four complexity components into one index: actions logic complexity (ALC), actions size complexity (ASC), information control exchange complexity (ICEC), and control mode complexity (CMC).To
verify the measurement, we calculated 11 tasks during the takeoff and landing phases from the SOPs, and invited 10 pilots to perform the same tasks in a flight simulator. After flight, the TCIF results were compared with two workload measurements: the Bedford scale and heart rate.RESULTS:
The results of TCIF and the 4 components of the 11 tasks were calculated. Further, the TCIF results showed a significant correlation with the Bedford scores (R = 0.851) and were also consistent with the difference in heart rate (R = 0.816). Therefore, with the increased TCIF results, both
the Bedford scale and the difference in heart rate increased.DISCUSSION: TCIF was proposed based on the flight operating conditions. Although additional studies of TCIF are necessary, the results of this study suggest this measurement could effectively indicate task complexity in
flight, and could also be used to guide pilot training and task allocation on the flight deck.Zheng Y, Lu Y, Wang Z, Huang D, Fu S. Developing a measurement for task complexity in flight. Aerosp Med Hum Perform. 2015; 86(8):698–704.
A Cognitive and Virtual Reality Treatment Program for the Fear of Flying
Authors: Ferrand Margot , Ruffault Alexis , Tytelman Xavier , Flahault Cécile , Négovanska Vélina
Published: July 2015

BACKGROUND: Passenger air transport has considerably increased in the past 50 yr. It is estimated that between 7 and 40% of the population of industrialized countries is currently afraid of flying. Programs treating the fear of flying have been developed to meet this problem.
This study measures the effectiveness of one of these programs by focusing on flight-related anxiety before the program and after the first flight following the intervention.METHODS: There were 157 individuals recruited to participate in a 1-d intervention aiming at treating the
fear of flying, and using both cognitive behavioral techniques and virtual reality. Anxiety was measured with the Flight Anxiety Situations (FAS) and the Flight Anxiety Modality (FAM) questionnaires.RESULTS: Statistical analyses were conducted on 145 subjects (69.7% female; ages
from 14 to 64) after the exclusion of individuals with missing data. The results showed a decrease in flight-related anxiety for each subscale of the two questionnaires: the somatic (d = 2.44) and cognitive anxiety (d = 1.47) subscales of the FAM, and the general flight anxiety (d = 3.20),
the anticipatory flight anxiety (d = 1.74), and the in-flight anxiety (d = 1.04) subscales of the FAS.CONCLUSIONS: The effectiveness of the treatment program using both cognitive behavioral techniques and virtual reality strategies for fear of flying reduced flight-related anxiety
in the subjects in our study. Our results show that subjects demonstrated lower anxiety levels after the first flight following the program than before the intervention.Ferrand M, Ruffault A, Tytelman X, Flahault C, Négovanska V. A cognitive and virtual reality treatment program
for the fear of flying. Aerosp Med Human Perform. 2015; 86(8):723–727.
Evaluating the Reliability of the Human Factors Analysis and Classification System
Authors: Cohen Tara N. , Wiegmann Douglas A. , Shappell Scott A.
Published: July 2015

INTRODUCTION: This paper examines the reliability of the Human Factors Analysis and Classification System (HFACS) as tool for coding human error and contributing factors associated with accidents and incidents.METHODS: A systematic review of articles published across
a 13-yr period between 2001 and 2014 revealed a total of 14 peer-reviewed manuscripts that reported data concerning the reliability of HFACS.RESULTS: Results revealed that the majority of these papers reported acceptable levels of interrater and intrarater reliability.CONCLUSION:
Reliability levels were higher with increased training and sample sizes. Likewise, when deviations from the original framework were minimized, reliability levels increased. Future applications of the framework should consider these factors to ensure the reliability and utility of HFACS as
an accident analysis and classification tool.Cohen TN, Wiegmann DA, Shappell SA. Evaluating the reliability of the Human Factors Analysis and Classification System. Aerosp Med Hum Perform. 2015; 86(8):728–735.
In-Flight Study of Helmet-Mounted Symbology System Concepts in Degraded Visual Environments
Authors: Cheung Bob , Craig Gregory , Steels Brad , Sceviour Robert , Cosman Vaughn , Jennings Sion , Holst Peter
Published: July 2015

BACKGROUND: During approach and departure in rotary wing aircraft, a sudden loss of external visual reference precipitates spatial disorientation.METHODS: There were 10 Royal Canadian Air Force (RCAF) Griffon pilots who participated in an in-flight investigation of
a 3-dimensional conformal Helmet Display Tracking System (HDTS) and the BrownOut Symbology System (BOSS) aboard an Advanced System Research Aircraft. For each symbology system, pilots performed a two-stage departure followed by a single-stage approach. The presentation order of the two symbology
systems was randomized across the pilots. Subjective measurements included situation awareness, mental effort, perceived performance, perceptual cue rating, NASA Task Load Index, and physiological response. Objective performance included aircraft speed, altitude, attitude, and distance from
the landing point, control position, and control activity. Repeated measures analysis of variance and planned comparison tests for the subjective and objective responses were performed.RESULTS: For both maneuvers, the HDTS system afforded better situation awareness, lower workload,
better perceptual cueing in attitude, horizontal and vertical translation, and lower overall workload index. During the two-stage departure, HDTS achieved less lateral drift from initial takeoff and hover, lower root mean square error (RMSE) in altitude during hover, and lower track error
during the acceleration to forward flight. During the single-stage approach, HDTS achieved less error in lateral and longitudinal position offset from the landing point and lower RMSE in heading.DISCUSSION: In both maneuvers, pilots exhibited higher control activity when using HDTS,
which suggested that more pertinent information was available to the pilots. Pilots preferred the HDTS system.Cheung B, Craig G, Steels B, Sceviour R, Cosman V, Jennings S, Holst P. In-flight study of helmet-mounted symbology system concepts in degraded visual environments. Aerosp
Med Hum Perform. 2015; 86(8):714–722.
Eosinophilic Esophagitis with Dysphagia and Food Impaction in a Young Adult
Authors: Cochet Anthony A. , Cochet Allyson E. , Francis James M.
Published: July 2015

BACKGROUND: Eosinophilic esophagitis (EoE) is an emerging esophageal disease associated with dysphagia and food impaction. Practice guidelines have only recently been developed. It affects 1/1000 individuals, predominantly young men. As this demographic represents a substantial
portion of the military aviation population, aerospace medicine clinicians should be familiar with this diagnosis when evaluating dysphagia or impactions.CASE REPORT: A 23-yr-old Caucasian man, a U.S. Air Force air traffic controller, presented to Flight Medicine following an episode
of food impaction requiring evaluation in the local emergency department. The patient reported a 5-yr history of recurrent episodes of food lodging in his throat, requiring fluid and body repositioning for resolution. Medical history was significant for eczema. Upper endoscopy revealed an
abnormal esophagus with macroscopic features of EoE and biopsies were also consistent with EoE. After further work-up, the patient was diagnosed with EoE and treated. Significant symptom improvement was noted after 2 mo of therapy.DISCUSSION: This case outlines the evaluation of
food impaction as well as the diagnostic criteria for EoE, which is a disease that affects patients with demographics common to the military aviation community. As the diagnostic and treatment guidelines for EoE are relatively new, it may easily be overlooked by the primary care physician,
causing a delay in subspecialist consultation, thus delaying treatment. EoE is a condition with symptoms that pose high risk to the performance of aircrew duties; therefore, flight surgeons must be familiar with the aeromedical standards that accompany this diagnosis.Cochet AA Jr, Cochet
AE, Francis JM. Eosinophilic esophagitis with dysphagia and food impaction in a young adult. Aerosp Med Hum Perform. 2015; 86(8):742–746.
Cerebral Blood Flow Velocity During Combined Lower Body Negative Pressure and Cognitive Stress
Authors: Durocher John J. , Carter Jason R. , Cooke William H. , Young Angelea H. , Harwood Morton H.
Published: July 2015

BACKGROUND: Lower body negative pressure (LBNP) decreases middle cerebral artery blood velocity (MCAv) and can induce hypotension. Mental stress increases MCAv, but the MCAv response to combined LBNP and mental stress (COMBO) is unknown. We hypothesized that performing a stressful
cognitive challenge (i.e., mental stress) concurrently with LBNP would prevent LBNP-induced reductions of MCAv.METHODS: There were 18 subjects (9 men, 9 women; ages 20.1 ± 0.3 yr) who completed 3 randomized 3-min trials: 1) LBNP (−40 mmHg); 2) mental stress (serial
subtraction); and 3) COMBO (LBNP + mental stress). All reported values are mean ± SE. Mean arterial pressure (MAP), heart rate (HR), forearm blood flow (FBF), and MCAv were measured continuously. Subjects also reported perceived stress following the mental stress and COMBO trials.RESULTS:
LBNP decreased MAP (−1.4 ± 0.5 mmHg), MCAv (−2.6 ± 1.1 cm s−1) and FBF (−0.8 ± 0.1 units), and increased HR (2.7 ± 1.2 bpm). Mental stress increased MAP (10.1 ± 1.3 mmHg), HR (17.4 ± 2.2 bpm), and FBF (2.4 ±
0.4 units), while MCAv (2.8 ± 1.3 cm s−1) tended to increase. COMBO increased MAP (5.3 ± 2.3 mmHg) and HR (21.3 ± 2.6 bpm), and tended to increase FBF (0.5 ± 0.3 units). However, MCAv (-4.6 ± 2.0 cm s−1) decreased during
COMBO. Decreases in MCAv during COMBO were not statistically different from LBNP-induced decreases (−4.6 ± 2.0 vs. −2.6 ± 1.1 cm s−1). Subjective ratings of perceived stress (standard 0 to 4 scale) tended to be higher during COMBO than mental stress
(2.9 ± 0.1 vs. 2.5 ± 0.1 units).CONCLUSION: Our results suggest that mental stress does not effectively preserve MCAv when combined with central hypovolemia (i.e., LBNP).Durocher JJ, Carter JR, Cooke WH, Young AH, Harwood MH. Cerebral blood flow velocity during
combined lower body negative pressure and cognitive stress. Aerosp Med Hum Perform. 2015; 86(8):688692.
A Modified Protocol for Color Vision Screening Using Ishihara
Authors: Chorley Adrian C.
Published: July 2015

INTRODUCTION: The Ishihara plates are commonly used as an initial occupational screening test for color vision. While effective at detecting red-green deficiencies, the color deficient subject can learn the test using different techniques. Some medical standards such as the European
Aviation Safety Agency (EASA) require plate randomization and apply a stricter pass/fail requirement than suggested by Ishihara. This has been reported to increase the false positive rate up to ∼50%.METHOD: Two modifications to the Ishihara protocol are investigated. These involved
allowing subjects a second attempt where one or two reading errors were made and the presentation of rotated Ishihara plates.RESULTS: A reduction of false positive rate to 5.9% was found. Correct identification of certain rotated Ishihara plates was not affected.DISCUSSION:
By using a modified Ishihara protocol, fewer color normal subjects would require unnecessary advanced color vision examination. Further, additional safeguards would be in place to ensure that no subject with a color vision deficiency could pass the Ishihara test.Chorley AC. A modified
protocol for color vision screening using Ishihara. Aerosp Med Hum Perform. 2015; 86(8):747–751.
Monitoring and Managing Cabin Crew Sleep and Fatigue During an Ultra-Long Range Trip
Authors: van den Berg Margo J. , Signal T. Leigh , Mulrine Hannah M. , Smith Alexander A. T. , Gander Philippa H. , Serfontein Wynand
Published: July 2015

BACKGROUND: The aims of this study were to monitor cabin crew fatigue, sleep, and performance on an ultra-long range (ULR) trip and to evaluate the appropriateness of applying data collection methods developed for flight crew to cabin crew operations under a fatigue risk management
system (FRMS).METHODS: Prior to, throughout, and following the ULR trip (outbound flight ULR; mean layover duration = 52.6 h; inbound flight long range), 55 cabin crew (29 women; mean age 36.5 yr; 25 men; mean age 36.6 yr; one missing data) completed a sleep/duty diary and wore
an actigraph. Across each flight, crewmembers rated their fatigue (Samn-Perelli Crew Status Check) and sleepiness (Karolinska Sleepiness Scale) and completed a 5-min Psychomotor Vigilance Task (PVT) at key times.RESULTS: Of crewmembers approached, 73% (N = 134) agreed to
participate and 41% (N = 55) provided data of suitable quality for analysis. In the 24 h before departure, sleep averaged 7.0 h and 40% took a preflight nap. All crewmembers slept in flight (mean total sleep time = 3.6 h outbound, 2.9 h inbound). Sleepiness and fatigue were lower, and
performance better, on the longer outbound flight than on the inbound flight. Post-trip, crewmembers slept more on day 1 (mean = 7.9 h) compared to baseline days, but there was no difference from day 2 onwards.DISCUSSION: The present study demonstrates that cabin crew fatigue can
be managed effectively on a ULR flight and that FRMS data collection is feasible for cabin crew, but operational differences between cabin crew and flight crew need to be considered.van den Berg MJ, Signal TL, Mulrine HM, Smith AAT, Gander PH, Serfontein W. Monitoring and managing cabin
crew sleep and fatigue during an ultra-long range trip. Aerosp Med Hum Perform. 2015; 86(8):705–713.
Personnel Selection Influences on Remotely Piloted Aircraft Human-System Integration
Authors: Carretta Thomas R. , King Raymond E.
Published: July 2015

INTRODUCTION: Human-system integration (HSI) is a complex process used to design and develop systems that integrate human capabilities and limitations in an effective and affordable manner. Effective HSI incorporates several domains, including manpower, personnel and training,
human factors, environment, safety, occupational health, habitability, survivability, logistics, intelligence, mobility, and command and control. To achieve effective HSI, the relationships among these domains must be considered. Although this integrated approach is well documented, there
are many instances where it is not followed. Human factors engineers typically focus on system design with little attention to the skills, abilities, and other characteristics needed by human operators. When problems with fielded systems occur, additional training of personnel is developed
and conducted. Personnel selection is seldom considered during the HSI process. Complex systems such as aviation require careful selection of the individuals who will interact with the system. Personnel selection is a two-stage process involving select-in and select-out procedures. Select-in
procedures determine which candidates have the aptitude to profit from training and represent the best investment. Select-out procedures focus on medical qualification and determine who should not enter training for medical reasons. The current paper discusses the role of personnel selection
in the HSI process in the context of remotely piloted aircraft systems.Carretta TR, King RE. Personnel selection influences on remotely piloted aircraft human-system integration. Aerosp Med Hum Perform. 2015; 86(8):736–741.
GENETIC ALGORITHMS FOR MULTIDIMENSIONAL SCALING / GENETINIŲ ALGORITMŲ TAIKYMAS DAUGIAMATĖMS SKALĖMS
Authors: Dzidolikaitė Agnė
Published: July 2015

The paper analyzes global optimization problem. In order to solve this problem multidimensional scaling algorithm is combined with genetic algorithm. Using multidimensional scaling we search for multidimensional data projections in a lower-dimensional space and try to keep dissimilarities of the set that we analyze. Using genetic algorithms we can get more than one local solution, but the whole population of optimal points. Different optimal points give different images. Looking at several multidimensional data images an expert can notice some qualities of given multidimensional data. In the paper genetic algorithm is applied for multidimensional scaling and glass data is visualized, and certain qualities are noticed. Analizuojamas globaliojo optimizavimo uždavinys. Jis apibrėžiamas kaip netiesinės tolydžiųjų kintamųjų tikslo funkcijos optimizavimas leistinojoje srityje. Optimizuojant taikomi įvairūs algoritmai. Paprastai taikant tikslius algoritmus randamas tikslus sprendinys, tačiau tai gali trukti labai ilgai. Dažnai norima gauti gerą sprendinį per priimtiną laiko tarpą. Tokiu atveju galimi kiti – euristiniai, algoritmai, kitaip dar vadinami euristikomis. Viena iš euristikų yra genetiniai algoritmai, kopijuojantys gyvojoje gamtoje vykstančią evoliuciją. Sudarant algoritmus naudojami evoliuciniai operatoriai: paveldimumas, mutacija, selekcija ir rekombinacija. Taikant genetinius algoritmus galima rasti pakankamai gerus sprendinius tų uždavinių, kuriems nėra tikslių algoritmų. Genetiniai algoritmai taip pat taikytini vizualizuojant duomenis daugiamačių skalių metodu. Taikant daugiamates skales ieškoma daugiamačių duomenų projekcijų mažesnio skaičiaus matmenų erdvėje siekiant išsaugoti analizuojamos aibės panašumus arba skirtingumus. Taikant genetinius algoritmus gaunamas ne vienas lokalusis sprendinys, o visa optimumų populiacija. Skirtingi optimumai atitinka skirtingus vaizdus. Matydamas kelis daugiamačių duomenų variantus, ekspertas gali įžvelgti daugiau daugiamačių duomenų savybių. Straipsnyje genetinis algoritmas pritaikytas daugiamatėms skalėms. Parodoma, kad daugiamačių skalių algoritmą galima kombinuoti su genetiniu algoritmu ir panaudoti daugiamačiams duomenims vizualizuoti.
BUSINESS PROCESS SIMULATION: REQUIREMENTS FOR BUSINESS AND RESOURCE MODELS / VERSLO PROCESŲ SIMULIACIJA: VERSLO PROCESŲ IR IŠTEKLIŲ MODELIŲ REIKALAVIMAI
Authors: Rima Audrius
Published: July 2015

The purpose of Business Process Model and Notation (BPMN) is to provide easily understandable graphical representation of business process. Thus BPMN is widely used and applied in various areas one of them being a business process simulation. This paper addresses some BPMN model based business process simulation problems. The paper formulate requirements for business process and resource models in enabling their use for business process simulation. Pagrindinis verslo procesų modeliavimo kalbos (angl. Business Process Model and Notation, BPMN) tikslas yra paprastai ir suprantamai atvaizduoti grafiškai verslo procesų modelius. BPMN naudojama vis plačiau, ją bandoma pritaikyti įvairiose srityse. Viena iš sričių yra verslo procesų simuliacija, t. y. verslo proceso vyksmo atkūrimas programinėmis priemonėmis. Straipsnyje aprašomos verslo procesų simuliacijos, grindžiamos BPMN modeliais, problemos. Formuluojami išteklių ir verslo proceso modeliui keltini reikalavimai, kad šiuos modelius būtų galima panaudoti simuliacijai.
AN INVESTIGATION OF ABF++, LSCM AND ARAP METHODS FOR PARAMETRIZATION OF SHOETREES / KURPALIŲ IŠKLOTINIŲ SUDARYMO TAIKANT PARAMETRIZAVIMO METODUS ABF++, LSCM, ARAP TYRIMAS
Authors: Sabaliauskas Martynas , Marcinkevičius Virginijus
Published: July 2015

This paper discusses on the numerical model flattening algorithms enabling the representation of straightened surface of three-dimensional objects in the plane. These algorithms are widely used in the engineering industry which requires a precise representation of surfaces of various fragments of 2D maps, such as the automotive industry. One of the examples of the application in the manufacture of footwear could be automatic formation of molds using shoetrees, which are usually produced by a unit ignoring the fact that manufacturers are still using wax foil for flattening. This paper provides an investigation of the most widely used 3D object surface flattening algorithms and also the comparison of molds of shoetrees obtained by these methods.
Apžvelgiami skaitmeninių modelių paviršių išklotinių sudarymo algoritmai ABF++, LSCM, ARAP, pagal kuriuos trimačių objektų paviršiai atvaizduojami ištiesinti plokštumoje. Šie išklotinių sudarymo algoritmai plačiai taikomi ne tik 3D skaitmeninių modelių tekstūroms generuoti bei atkurti, bet ir pramonės inžinerijoje, kur būtina įvairių detalių paviršių fragmentus tiksliai atvaizduoti plokštumoje. Vienas iš taikymo pavyzdžių avalynės gamyboje galėtų būti automatinis lekalų sudarymas pagal įvairius kurpalių modelius, kurie dažniausiai gaminami vienetiniams gaminiams. Iki šiol paviršiaus išklotinei sudaryti naudojama vaško folija. Atliktas tyrimas parodė, kad iš kurpalių išklotinių, gautų remiantis teoriniais metodais, geriausių rezultatų pasiekta taikant ARAP algoritmą, tačiau jis nėra pakankamai tikslus, kad būtų galima tiesiogiai taikyti avalynės gamyboje.
HEART BEAT DETECTION IN NOISY ECG SIGNALS USING STATISTICAL ANALYSIS OF THE AUTOMATICALLY DETECTED ANNOTATIONS / ŠIRDIES DŪŽIŲ NUSTATYMAS IŠ IŠKRAIPYTŲ EKG SIGNALŲ ATLIEKANT AUTOMATIŠKAI APTIKTŲ ATSKAITŲ STATISTINĘ ANALIZĘ
Authors: Gudiškis Andrius
Published: July 2015

This paper proposes an algorithm to reduce the noise distortion influence in heartbeat annotation detection in electrocardiogram (ECG) signals. Boundary estimation module is based on energy detector. Heartbeat detection is usually performed by QRS detectors that are able to find QRS regions in a ECG signal that are a direct representation of a heartbeat. However, QRS performs as intended only in cases where ECG signals have high signal to noise ratio, when there are more noticeable signal distortion detectors accuracy decreases. Proposed algorithm uses additional data, taken from arterial blood pressure signal which was recorded in parallel to ECG signal, and uses it to support the QRS detection process in distorted signal areas. Proposed algorithm performs as well as classical QRS detectors in cases where signal to noise ratio is high, compared to the heartbeat annotations provided by experts. In signals with considerably lower signal to noise ratio proposed algorithm improved the detection accuracy to up to 6%.
Širdies ritmas yra vienas svarbiausių ir daugiausia informacijos apie pacientų būklę teikiančių fiziologinių parametrų. Širdies ritmas nustatomas iš elektrokardiogramos (EKG), atliekant QRS regionų, kurie yra interpretuojami kaip širdies dūžio ãtskaitos, paiešką. QRS regionų aptikimas yra klasikinis uždavinys, nagrinėjamas jau keletą dešimtmečių, todėl širdies dūžių nustatymo iš EKG signalų metodų yra labai daug. Deja, šie metodai tikslūs ir patikimi tik esant dideliam signalo ir triukšmo santykiui. Kai EKG signalai labai iškraipomi, QRS aptiktuvai ne visada gali atskirti QRS regioną, o kartais jį randa ten, kur iš tikro jo būti neturėtų. Straipsnyje siūlomas algoritmas, kurį taikant sumažinama triukšmo įtaka nustatant iš EKG signalų QRS regionus. Tam naudojamas QRS aptiktuvas, kartu prognozuojantis širdies dūžio atskaitą. Remiamasi arterinio kraujo spaudimo signalo duomenimis, renkama atskaitų statistika ir atliekama jos analizė.
AUTOMATIC PLANNING OF EXTERNAL SEARCH ENGINE OPTIMIZATION / AUTOMATIZUOTAS IŠORINIO PAIEŠKOS SISTEMŲ OPTIMIZAVIMO PLANAVIMAS
Authors: Jasevičiūtė Vita
Published: July 2015

This paper describes an investigation of the external search engine optimization (SEO) action planning tool, dedicated to automatically extract a small set of most important keywords for each month during whole year period. The keywords in the set are extracted accordingly to external measured parameters, such as average number of searches during the year and for every month individually. Additionally the position of the optimized web site for each keyword is taken into account. The generated optimization plan is similar to the optimization plans prepared manually by the SEO professionals and can be successfully used as a support tool for web site search engine optimization.
Straipsnyje sprendžiami paieškos sistemų (angl. SEO) išorinio optimizavimo planavimo klausimai. Pateikiama jo automatizavimo koncepcija. Turint reikšminių žodžių sąrašą, jų esamas vietas paieškos sistemos rezultatuose, vidutinį paieškų skaičių per metus, apskaičiuojami reikšminių žodžių svoriai. Pagal šiuos svorius, remiantis suformuluota koncepcija, nustatoma, kiek mėnesių šį reikšminį žodį reikia optimizuoti. Stebint atliekamų paieškų skaičiaus vidurkius, kiekvieną mėnesį apskaičiuojami maksimumai. Tada parengiamas išorinio optimizavimo planas, sudaromi optimizuotinų reikšminių žodžių rinkiniai konkrečiam mėnesiui. Gautas planas labai panašus į tuos, kurie sudaromi rankiniu būdu, todėl tai įgyvendinus programa, t. y. automatizavus, būtų sutaupoma nemažai laiko ir atsisakoma papildomų rutininių darbų.
DEVELOPMENT OF CONTROL SYSTEM FOR AUTOMATED MANIPULATOR / AUTOMATINIO MANIPULIATORIAUS VALDYMO SISTEMA
Authors: Autsou Siarhei , Karpovich Dzmitry , Saroka Viktar
Published: July 2015

The paper is devoted to investigation of manipulators for plating lines and their modes of operation, as well as the development of a control system for gantry autooperator (LLC KTM-2000). The manipulator motion cyclograms for a given technological regulations were developed and presented.
Analizuojama galvaninio padengimo linijos automatinio manipuliatoriaus valdymo sistema, apibendrinamos išvados. Pateiktos pagal nustatytą technologinio proceso aprašą sudarytos judėjimo ciklogramos bei loginės funkcijos.
INVESTIGATION OF THE ROBUST STABILITY OF SYSTEM WITH DELAY / SISTEMŲ, KURIŲ SAVYBĖ VĖLINTI, TYRIMAS PATIKIMAM STABILUMUI NUSTATYTI
Authors: Shumski Andrei , Karpovich Dzmitry
Published: July 2015

The paper is devoted to investigation of the robust stability of system with delay. The influence of process parameters on the stability of the whole system is tested and impact to the system parameters using the Smith predictor for robust systems is defined.
Pristatomas sistemų, kurioms būdingas vėlinimas, tyrimas patikimam stabilumui nustatyti. Ištirta proceso parametrų įtaka visos sistemos stabilumui ir įvertinta Smito prognozės taikymo nauda numatant patikimas sistemas.
RESEARCH OF LIQUID LEVEL CONTROL SYSTEM / SKYSČIO LYGIO VALDYMO SISTEMOS TYRIMAS
Authors: Beištaras Dominykas
Published: July 2015

This paper presents liquid level control system model and analysis of dynamic characteristics. The system consists of scalar controlled induction motor drive, fuzzy logic controller, water tank and centrifugal pump. Simulink models of water tank, pump and controller are presented. The simulation of the system shows that the use of fuzzy logic controller reduces valve opening time and reservoir filling time.
Nagrinėjamas skysčio lygio valdymo sistemos imitacinių modelių sudarymas, analizuojamos dinaminės charakteristikos. Valdymo sistema sudaryta iš skaliariniu būdu valdomos dažninės elektros pavaros su neraiškiosios logikos reguliatoriumi, vandens rezervuaro ir išcentrinio siurblio. Sudaryti rezervuaro, siurblio ir reguliatoriaus Simulink modeliai. Atlikus imitacijas gauta nedimensinė siurblio charakteristika, apibūdinanti siurblio veikimą, esant bet kokiam sukimosi greičiui. Nustatyta, kad sistemoje su neraiškiosios logikos reguliatoriumi vožtuvas yra atidaromas greičiau nei sistemoje su proporcinguoju integraliniu (PI) reguliatoriumi, ir todėl sumažinama rezervuaro pripildymo trukmė.
DEVELOPMENT AND INVESTIGATION OF AN OPTICAL POWER METER FRONT END / OPTINĖS GALIOS MATUOKLIO ĮĖJIMO PAKOPOS PROJEKTAVIMAS IR TYRIMAS
Authors: Korsakas Edgaras , Charlamov Jevgenij
Published: July 2015

Circuit of the classical transimpedance amplifier (TIA) is revised and improved circuit is developed. Analytical solutions for the classical and improved circuits are derived. Both circuits were built and their parameters were measured. An experiment results showed that improved TIA achieves 4.5 dB greater dynamic rage than the classical TIA at +50 °C and 12 dB greater at –10 °C.
Išanalizuota klasikinė pereinamosios varžos stiprintuvo (PVS) schema. Nustatyti stiprintuvo trūkumai, sudaryta patobulinta PVS schema. Išvestos klasikinės ir patobulintosios stiprintuvų schemų analitinės išraiškos, parodyta, kad patobulinto stiprintuvo išėjimo įtampos slinkis plačiame temperatūrų diapazone bus mažesnis. Atlikus eksperimentą gauti matavimų rezultatai parodė, kad patobulintos PVS schemos dinaminis diapazonas 4,5 dB didesnis negu klasikinės PVS schemos, temperatūroms esant nuo –10 °C iki +50 °C.
TEMPERATURE EFFECT TO SOLAR POWER PLANT / TEMPERATŪROS ĮTAKA FOTOVOLTINEI JĖGAINEI
Authors: Pikutis Modestas
Published: July 2015

There are a lot of different efficiency photovoltaic cells, which are used in solar power plants. All of these different photovoltaic cells are affected by different environment conditions. Maximum power point tracking is the main way to increase solar power plant efficiency. Mostly systems of maximum power point tracking are slow or inaccurate, that means the system cannot stay in maximum power point in solar power plant. This is the main reason why mostly of solar power plants are working not efficiently. The use of real working solar power plant with aim to find more efficient control algorithms is very expensive and requires long development period. Mathematical modeling makes research and investigation faster. In this article a temperature changing block of photovoltaic module that can simulate temperature changing process for month or even a few years was proposed. This temperature block was used in a solar power plant model which was created in previous investigations. Now, solar power plant model has four structural blocks: solar irradiance block, temperature of photovoltaic module block, photovoltaic module block and controller block. IncCond algorithm is used for maximum power point tracking. Solar power plant model is implemented in Matlab/Simulink environment. This model enables to analyze solar power plant working efficiency, when there are no clouds and the temperature is changing or stays constant.
Fotovoltinėse jėgainėse naudojami įvairaus tipo skirtingo veikimo efektyvumo saulės elementai. Nors šie elementai pagal tipą ir efektyvumą skirtingi, tačiau visiems jiems didelę įtaką daro aplinkos sąlygos. Pagrindinė priemonė fotovoltinės jėgainės (FJ) efektyvumui didinti yra didžiausios galios taško sekimas (DGT). Dauguma valdiklių, skirtų didžiausios galios taškui sekti fotovoltinėje jėgainėje, yra lėti arba netikslūs – negali palaikyti fotovoltinės jėgainės didžiausios galios režimo. Tai pagrindinė fotovoltinės jėgainės neefektyvaus veikimo priežastis. Fotovoltinių jėgainių tyrimams realiomis eksploatavimo sąlygomis ieškant efektyvesnių valdymo algoritmų būtinos didelės investicijos į įrangą, ir tai ilgai trunka. Tyrimams paspartinti kuriami imitaciniai modeliai. Šiame darbe aprašomas sukurtas temperatūros poveikiui tirti skirtas saulės modulio temperatūros kitimo blokas. Tai galimybė imituoti procesus, trunkančius mėnesį ar net kelerius metus. Darbe analizuojamą FJ modelį sudaro keturi struktūriniai blokai: saulės galios srautą imituojantis blokas, temperatūros kitimą imituojantis blokas, saulės modulių imitatorius ir valdymo algoritmas, kuriame didžiausios galios taškas nustatomas pagal IncCond algoritmą. Visas fotovoltinės jėgainės modelis, įgyvendintas Matlab/Simulink terpėje, leido analizuoti fotovoltinės jėgainės veikimo efektyvumą giedrą dieną, kai modulių temperatūra buvo pastovi arba kito.
NETWORK TRAFFIC ANOMALIES IDENTIFICATION BASED ON CLASSIFICATION METHODS / TINKLO SRAUTO ANOMALIJŲ IDENTIFIKAVIMAS, TAIKANT KLASIFIKAVIMO METODUS
Authors: Račys Donatas , Mažeika Dalius
Published: July 2015

A problem of network traffic anomalies detection in the computer networks is analyzed. Overview of anomalies detection methods is given then advantages and disadvantages of the different methods are analyzed. Model for the traffic anomalies detection was developed based on IBM SPSS Modeler and is used to analyze SNMP data of the router. Investigation of the traffic anomalies was done using three classification methods and different sets of the learning data. Based on the results of investigation it was determined that C5.1 decision tree method has the largest accuracy and performance and can be successfully used for identification of the network traffic anomalies.
Straipsnyje nagrinėjama kompiuterių tinklo srauto anomalijų atpažinimo problema. Apžvelgiami kompiuterių tinklų anomalijų aptikimo metodai bei aptariami jų privalumai ir trūkumai. Naudojant IBM SPSS Modeler programų paketą sudarytas nagrinėjamo tinklo srauto anomalijų atpažinimo modelis, pritaikytas SNMP protokolu pagrįstiems maršruto parinktuvo duomenims apdoroti. Pagal tris klasifikavimo metodus ir skirtingus mokymui skirtus duomenų rinkinius atlikti skaičiavimai tinklo anomalijoms identifikuoti. Palyginant gautus rezultatus nustatyta, kad C5.1 sprendimo medžio algoritmas yra tiksliausias ir sparčiausias, todėl ir tinkamiausias tinklo srauto anomalijoms atpažinti.
APPLYING GAME THEORY IN 802.11 WIRELESS NETWORKS / ŽAIDIMŲ TEORIJOS TAIKYMAS IEEE 802.11 TINKLUOSE
Authors: Cuzanauskas Tomas , Anskaitis Aurimas
Published: July 2015

IEEE 802.11 is one of the most popular wireless technologies in recent days. Due to easiness of adaption and relatively low cost the demand for IEEE 802.11 devices is increasing exponentially. IEEE works in two bands 2.4 GHz and 5 GHz, these bands are known as ISM band. The unlicensed bands are managed by authority which set simple rules to follow when using unlicensed bands, the rules includes requirements as maximum power, out-of-band emissions control as well as interference mitigation. However these rules became outdated as IEEE 802.11 technology is emerging and evolving in hours the rules aren’t well suited for current capabilities of IEEE 802.11 devices. In this article we present game theory based algorithm for IEEE 802.11 wireless devices, we will show that by using game theory it’s possible to achieve better usage of unlicensed spectrum as well as partially decline CSMA/CA. Finally by using this approach we might relax the currently applied maximum power rules for ISM bands, which enable IEEE 802.11 to work on longer distance and have better propagation characteristics.
Lengvai pritaikoma ir panaudojama įvairiuose sprendimuose IEEE 802.11 technologija tapo viena populiariausių bevielių technologijų. IEEE 802.11 įrenginiai veikia nelicencijuotais 5 GHz ir 2,4 GHz dažniais – pramonės, mokslo ir medicinos dažnių ruože (angl. Industrial, scientific and medical (ISM) radio bands). Šiam dažnių ruožui taikomos supaprastintos taisyklės, nurodančios, kad įrenginiai, veikiantys ISM dažniais, turi atitikti tik maksimalią signalo perdavimo galią ir interferencijos triukšmus bei neviršyti triukšmo normos už dažnių ruožo ribų. Tobulėjant IEEE 802.11 protokolo įrangai, šios taisyklės tapo nelanksčios ir neatitinka dabartinių įrenginių galimybių. Straipsnyje pristatomas naujas IEEE 802.11 įrenginių kanalo prieigos metodas, pagrįstas žaidimų teorija. Parodoma, kad taikant šį metodą galima pagerinti spektro panaudojimo efektyvumą bei kartu iš dalies atsisakyti dabar egzistuojančio CSMA/CA mechanizmo IEEE 802.11 įrenginiuose. Taikant efektyvesnį kanalo prieigos metodą atsiranda galimybė laikytis lankstesnių siųstuvo galių taisyklių ir taip padidinti skvarbą uždarose patalpose bei įrangos veikimo nuotolį.
INVESTIGATION OF LOAD SHARING IN HYBRID (2G/3G) MOBILE NETWORKS / HIBRIDINIŲ (2G/3G) KORINIO RYŠIO TINKLŲ SRAUTŲ VALDYMO TYRIMAS
Authors: Stirbys Martynas , Žvinys Karolis
Published: July 2015

The main purpose of this work is to investigate load sharing methods for 2G/3G cellular networks in order to determine their impact on the network and users. One of the study aims is to analyze the performance of the methods. Moreover the paper provides an overview of the methods circumstances, limitations. Directed Retry and Load Based Handover methods were chosen. Data was obtained from real Lithuanian mobile operator’s network. The paper also discusses the changes in Key Performance Indicators.
Pagrindinis darbo tikslas – ištirti vartotojų generuojamų informacijos srautų valdymo 2G/3G korinio ryšio tinkluose metodus, siekiant nustatyti jų įtaką tinklui ir vartotojams. Tyrimo metu analizuojamos įvairių srauto valdymo metodų taikymo tikslingumas, įvertinamos jų taikymo aplinkybės, ribojimai. Darbe supažindinama su srautų valdymo metodų įtaka tinklams ir vartotojams. Taikant Directed Retry ir LBHO (angl. Load Based Handover) srautų valdymo metodus analizuojami iš realaus Lietuvos mobiliojo ryšio operatoriaus tinklo gauti duomenys. Rezultatai apibūdinti įvertinus mobiliojo ryšio tinklo kokybinių rodiklių KPI (angl. Key Performance Indicators) pokyčius ir tam įtakos turinčius veiksnius.
THE IMPACT OF SPACE VECTOR SEQUENCE IN THE SWITCHING TABLE ON INVERTERS OUTPUT VOLTAGE / ERDVINIŲ VEKTORIŲ PERJUNGIMO TVARKOS ĮTAKA KOMUTAVIMO TRIUKŠMAMS DAŽNIO KEITIKLIO IŠĖJIMO ĮTAMPOJE
Authors: Lipinskis Tadas , Zlosnikas Valerijus
Published: July 2015

Multiphase AC machines are more reliable that three phase machines due to their ability to work when one or more phases fail. Also multiphase machines have higher starting torque, which enables them to start with heavier loads. Inverters are used to supply power and control parameters of an AC machine. In this paper a six phase inverter with a symmetrical star connected load with a single neutral is discussed. When the inverter's output voltage is formed by space vector pulse width modulation method, a high frequency harmonics appear in the output voltage, which increases power losses. The purpose of this work is to investigate what type of effect on output voltage harmonics has the sequence of space vectors in the switching table. Two methods of creating a switching table are presented in this paper, and two switching tables are created. Inverter's operation with both switching tables is simulated in Matlab/Simulink environment. Result analysis shows that changing the switching vector sequence in the switching table has an effect on output voltage harmonics of frequency around inverter's switching frequency. Daugiafaziai elektros varikliai yra patikimesni nei trifaziai dėl jų galimybės veikti dingus vienai ar daugiau fazių. Taip pat daugiafazių variklių startinis sukimo momentas yra didesnis, todėl šie varikliai gali pradėti veikti esant didesnei apkrovai. Daugiafaziams varikliams energijai tiekti ir valdyti naudojami dažnio keitikliai. Darbe nagrinėjamas šešių fazių dažnio keitiklis, apkrautas žvaigždės jungimo simetrine apkrova su viena neutrale. Formuojant įtampą erdvinių vektorių impulsų skvarbos moduliacijos metodu, keitiklio išėjimo įtampoje dėl raktų junginėjimo atsiranda komutavimo triukšmų, kurie sukelia energijos nuostolių. Darbo tikslas yra ištirti erdvinių vektorių perjungimo tvarkos įtaką išėjimo įtampos harmonikoms. Darbe tiriami komutavimo triukšmai esant dvejopiems erdvinio vektoriaus perjungimo tvarkos atvejams. Tyrimams naudoti Matlab/Simulink modeliai.
Alveolar Epithelial A2B Adenosine Receptors in Pulmonary Protection during Acute Lung Injury
Authors: Hoegl Sandra , Brodsky Kelley S. , Blackburn Michael R. , Karmouty-Quintana Harry , Zwissler Bernhard , Eltzschig Holger K.
Published: July 2015

Acute lung injury (ALI) is an acute inflammatory lung disease that causes morbidity and mortality in critically ill patients. However, there are many instances where ALI resolves spontaneously through endogenous pathways that help to control excessive lung inflammation. Previous studies have implicated the extracellular signaling molecule adenosine and signaling events through the A2B adenosine receptor in lung protection. In this context, we hypothesized that tissue-specific expression of the A2B adenosine receptor is responsible for the previously described attenuation of ALI. To address this hypothesis, we exposed mice with tissue-specific deletion of Adora2b to ALI, utilizing a two-hit model where intratracheal LPS treatment is followed by injurious mechanical ventilation. Interestingly, a head-to-head comparison of mice with deletion of Adora2b in the myeloid lineage (Adora2bloxP/loxP LysM Cre+), endothelial cells (Adora2bloxP/loxP VE-cadherin Cre+), or alveolar epithelial cells (Adora2bloxP/loxP SPC Cre+) revealed a selective increase in disease susceptibility in Adora2bloxP/loxP SPC Cre+ mice. More detailed analysis of Adora2bloxP/loxP SPC Cre+ mice confirmed elevated lung inflammation and attenuated alveolar fluid clearance. To directly deliver an A2B adenosine receptor–specific agonist to alveolar epithelial cells, we subsequently performed studies with inhaled BAY 60-6583. Indeed, aerosolized BAY 60-6583 treatment was associated with attenuated pulmonary edema, improved histologic lung injury, and dampened lung inflammation. Collectively, these findings suggest that alveolar epithelial A2B adenosine receptor signaling contributes to lung protection, and they implicate inhaled A2B adenosine receptor agonists in ALI treatment.
Copy Number Variations in CTNNA3 and RBFOX1 Associate with Pediatric Food Allergy
Authors: Li Jin , Fung Irene , Glessner Joseph T. , Pandey Rahul , Wei Zhi , Bakay Marina , Mentch Frank D. , Pellegrino Renata , Wang Tiancheng , Kim Cecilia , Hou Cuiping , Wang Fengxiang , Chiavacci Rosetta M. , Thomas Kelly A. , Spergel Jonathan M. , Hakonarson Hakon , Sleiman Patrick M. A.
Published: July 2015

Food allergy is a significant public health concern, especially among children. Previous candidate gene studies suggested a few susceptibility loci for food allergy, but no study investigated the contribution of copy number variations (CNVs) to food allergy on a genome-wide scale. To investigate the genetics of food allergy, we performed CNV assessment using high-resolution genome-wide single nucleotide polymorphism arrays. CNV calls from a total of 357 cases with confirmed food allergy and 3980 controls were analyzed within a discovery cohort, followed by a replication analysis composed of 167 cases and 1573 controls. We identified that CNVs in CTNNA3 were significantly associated with food allergy in both the discovery cohort and the replication cohort. Of particular interest, CTNNA3 CNVs hit exons or intron regions rich in histone marker H3K4Me1. CNVs in a second gene (RBFOX1) showed a significant association (p = 7.35 × 10−5) with food allergy at the genome-wide level in our meta-analysis of the European ancestry cohorts. The presence of these CNVs was confirmed by quantitative PCR. Furthermore, knockdown of CTNNA3 resulted in upregulation of CD63 and CD203c in mononuclear cells upon PMA stimulation, suggesting a role in sensitization to allergen. We uncovered at least two plausible genes harboring CNV loci that are enriched in pediatric patients with food allergies. The novel gene candidates discovered in this study by genome-wide CNV analysis are compelling drug and diagnostic targets for food allergy.
An Inhibitory Role for the Transcription Factor Stat3 in Controlling IL-4 and Bcl6 Expression in Follicular Helper T Cells
Authors: Wu Hao , Xu Lin-Lin , Teuscher Paulla , Liu Hong , Kaplan Mark H. , Dent Alexander L.
Published: July 2015

The transcription factor Bcl6 is required for development of follicular helper T (TFH) cells. Cytokines that activate Stat3 promote Bcl6 expression and TFH cell differentiation. Previous studies with an acute virus infection model showed that TFH cell differentiation was decreased but not blocked in the absence of Stat3. In this study, we further analyzed the role of Stat3 in TFH cells. In Peyer’s patches, we found that compared with wild-type, Stat3-deficient TFH cells developed at a 25% lower rate and expressed increased IFN-γ and IL-4. Whereas Peyer’s patch germinal center B cells developed at normal numbers with Stat3-deficient TFH cells, IgG1 class switching was greatly increased. Following immunization with sheep RBCs, splenic Stat3-deficient TFH cells developed at a slower rate than in control mice, and splenic germinal center B cells were markedly decreased. Stat3-deficient TFH cells developed poorly in a competitive bone marrow chimera environment. Under all conditions tested, Stat3-deficient TFH cells overexpressed both IL-4 and Bcl6, a pattern specific for the TFH cell population. Finally, we found in vitro that repression of IL-4 expression in CD4 T cells by Bcl6 required Stat3 function. Our data indicate that Stat3 can repress the expression of Bcl6 and IL-4 in TFH cells, and that Stat3 regulates the ability of Bcl6 to repress target genes. Overall, we conclude that Stat3 is required to fine-tune the expression of multiple key genes in TFH cells, and that the specific immune environment determines the function of Stat3 in TFH cells.
Noninvasive In Toto Imaging of the Thymus Reveals Heterogeneous Migratory Behavior of Developing T Cells
Authors: Bajoghli Baubak , Kuri Paola , Inoue Daigo , Aghaallaei Narges , Hanelt Marleen , Thumberger Thomas , Rauzi Matteo , Wittbrodt Joachim , Leptin Maria
Published: July 2015

The migration of developing T cells (thymocytes) between distinct thymic microenvironments is crucial for their development. Ex vivo studies of thymus tissue explants suggest two distinct migratory behaviors of thymocytes in the thymus. In the cortex, thymocytes exhibit a stochastic migration, whereas medullary thymocytes show confined migratory behavior. Thus far, it has been difficult to follow all thymocytes in an entire thymus and relate their differentiation steps to their migratory dynamics. To understand the spatial organization of the migratory behavior and development of thymocytes in a fully functional thymus, we developed transgenic reporter lines for the chemokine receptors ccr9a and ccr9b, as well as for rag2, and used them for noninvasive live imaging of the entire thymus in medaka (Oryzias latipes). We found that the expression of these two chemokine receptors in the medaka juvenile thymus defined two spatially distinct subpopulations of thymocytes. Landmark events of T cell development including proliferation, somatic recombination, and thymic selection can be mapped to subregions of the thymus. The migratory behavior of thymocytes within each of the subpopulations is equally heterogeneous, and specific migratory behaviors are not associated with particular domains in the thymus. During the period when thymocytes express rag2 their migratory behavior was more homogeneous. Therefore, the migratory behavior of thymocytes is partly correlated with their developmental stage rather than being defined by their spatial localization.