IN THIS PAPER, A METHOD FOR ESTIMATING SNOW PRESSURE REFLECTION COEFFICIENT BASED ON NON-CONTACT ULTRASOUND EXAMINATION IS DESCRIBED. A CONSTANT FREQUENCY AND AIR-COUPLED ULTRASOUND PULSES WERE USED IN THIS STUDY, WHICH INCORPORATES A PARAMETRIC METHOD FOR REFLECTED ENERGY ESTIMATION. THE EXPERIMENTAL PART WAS CARRIED OUT IN SITU IN THE ANTARCTIC, WHERE THE SNOW PARAMETERS WERE MEASURED ALONG WITH METEOROLOGICAL DATA. THE PROPOSED METHOD REPRESENTS A PROMISING ALTERNATIVE FOR ESTIMATING THE SNOW-WATER EQUIVALENT, SINCE IT USES A PARAMETRIC APPROACH, WHICH DOES NOT REQUIRE MEASUREMENTS OF ABSOLUTE VALUES FOR ACOUSTIC PRESSURE.

EN ESTE ARTÍCULO SE DISEÑA UN NUEVO CÓDIGO CÍCLICO BIDIMENSIONAL QUE CORRIGE ERROR DE RÁFAGA, TAMBIÉN DETECTA Y CORRIGE ERROR DE DESLIZAMIENTO. UNA DE LA CARACTERÍSTICA DEL RUIDO CLASE A ES QUE ESTÁ CONSTITUIDO POR UN RUIDO DE RÁFAGA EL CUAL AFECTA A VARIOS BITS CONSECUTIVOS MÁS UN RUIDO GAUSSIANO. ESTE TRABAJO PROPONE UN CÓDIGO BIDIMENSIONAL QUE PERMITE CUMPLIR DOS TAREAS, UNA DISMINUIR EL RUIDO DE RÁFAGA Y EL OTRO DISMINUIR EL ERROR DE SINCRONIZACIÓN QUE SE PRODUCE CUANDO EXISTE UN DESLIZAMIENTO DE BITS Y EL RECEPTOR RECUPERA LA INFORMACIÓN CON ERROR. PARA EVALUAR EL DESEMPEÑO SE SIMULA UN CANAL CON RUIDO CLASE A. SE GRAFICA LA RAZÓN SEÑAL A RUIDO VERSUS LA PROBABILIDAD DE ERROR DE BITS, PARA DIFERENTES TAMAÑOS DE CÓDIGOS CÍCLICOS BIDIMENSIONALES Y SE COMPARA CON CÓDIGOS CÍCLICOS UNIDIMENSIONAL. DE ACUERDO A LOS RESULTADOS QUE SE OBTIENEN, ESTE CÓDIGO MEJORA LA CONFIABILIDAD DEL SISTEMA DE COMUNICACIÓN CUANDO SE TRANSMITE POR UN CANAL CON RUIDO CLASE A, DISMINUYENDO EN FORMA SIGNIFICATIVA LA PROBABILIDAD DE ERROR DE BIT Y DE DESLIZAMIENTO. LA INVESTIGACIÓN QUEDA ABIERTA PARA LA CONSTRUCCIÓN DE NUEVOS CÓDIGOS BIDIMENSIONALES QUE PERMITAN DISMINUIR LA PROBABILIDAD DE ERROR DE RÁFAGA Y EL ERROR DE SINCRONIZACIÓN.

THIS PAPER ADDRESSES THE PROBLEM RELATED TO THE INTERPRETATION OF THE RESULTS OF ACTUAL SNOWFALL MEASUREMENTS PERFORMED WITH TWO DIFFERENT CONFIGURATIONS OF THE COMPENSATION METHODS FOR CHANGEABLE CLIMATIC CONDITIONS. THE PAPER ALSO PRESENTS THE OPERATING PRINCIPLE OF AN ULTRASOUND SENSOR FOR MONITORING SNOW LAYER (ON THE AIR-SIDE). IN PARTICULAR, THE PAPER INCLUDES A GRAPHIC REPRESENTATION OF THE RESULTS OF MEASUREMENTS PERFORMED IN MEASUREMENT STATIONS LOCATED IN POLAND AND AT SPITSBERGEN. THE TWO COMPENSATION METHODS (TEMPERATURE AND PARAMETRIC) WERE TESTED FOR THEIR EFFECTIVENESS IN DIFFERENT, CHANGEABLE CLIMATIC CONDITIONS. THE MEASUREMENT RESULTS CONFIRM THAT THE APPLIED COMPENSATION METHODS ARE USEFUL IN MINIMIZING THE MEASUREMENT ERROR FOR SNOW LAYER THICKNESS MEASURED ON THE AIR-SIDE.

ARE THE ONLY NATIVE VASCULAR SPECIES OF PLANTS IN THE ANTARCTICREGION AND ARE A SOURCE OF INTEREST IN THE CLIMATE CHANGE STUDIES.THESE PLANTS HAVE BEEN STUDIED FOR DECADES AND RECOGNIZEDAS BIOINDICATORS OF THE CLIMATE CHANGE. THE ARTICLE PRESENTSPRELIMINARY STUDIES AND RESULTS OF A THERMAL ACTUATOR, WHICH ISGOING TO BE APPLIED IN A CLIMATE CHANGE STUDIES. THE ELABORATED,FAR INFRARED ACTUATOR TOGETHER WITH A CONTROL SYSTEM MAINTAINSTHE TEMPERATURE OF THE ANTARCTIC PLANT CERTAIN DELTA ABOVE THEAMBIENT TEMPERATURE. SINCE THE HEAT TRANSFER IS BASED ON INFRAREDRADIATION A THERMAL MODEL IS INTRODUCED, WHERE THE PARAMETERSOF THE MODEL ARE DETERMINED EMPIRICALLY APPROXIMATING IT USING A1-ST ORDER DYNAMICAL SYSTEM. ONCE DETERMINED, THE SYTEM MODELPAREMETERS HELP TO DESIGN THE CONTROL STRATEGIES: CONTROL ON-OFF(1) AND CONTROL PID (PROPORTIONAL?INTEGRAL?DERIVATIVE) (2). ASA RESULT WE OBTAIN THAT THE CONTROL PID MAINTAINS THE OBJECTSTEMPERATURE WITH MAJOR STABILITY THAN ON-OFF, WHAT MAKES ITPREFERABLE IN THE ?NAL APPLICATION. THE FUTURE WORKS INVOLVEMODELING AMBIENTAL PERTURBATION, WHICH AFFECTS THE SYSTEM ANDDETERMINATION THERMAL PARAMETERS OF THE ANTARCTIC PLANTS.

COLOBANTHUS QUITENSIS AND DESCHAMPSIA ANTARTICA ARE THE ONLY NATIVE VASCULAR SPECIES OF PLANTS IN THE ANTARCTIC REGION AND ARE A SOURCE OF INTEREST IN THE CLIMATE CHANGE STUDIES. THESE PLANTS HAVE BEEN STUDIED FOR DECADES AND RECOGNIZED AS BIOINDICATORS OF THE CLIMATE CHANGE. THE ARTICLE PRESENTS PRELIMINARY STUDIES AND RESULTS OF A THERMAL ACTUATOR, WHICH IS GOING TO BE APPLIED IN A CLIMATE CHANGE STUDIES. THE ELABORATED, FAR INFRARED ACTUATOR TOGETHER WITH A CONTROL SYSTEM MAINTAINS THE TEMPERATURE OF THE ANTARCTIC PLANT CERTAIN DELTA ABOVE THE AMBIENT TEMPERATURE. SINCE THE HEAT TRANSFER IS BASED ON INFRARED RADIATION A THERMAL MODEL IS INTRODUCED, WHERE THE PARAMETERS OF THE MODEL ARE DETERMINED EMPIRICALLY APPROXIMATING IT USING A 1-ST ORDER DYNAMICAL SYSTEM. ONCE DETERMINED, THE SYTEM MODEL PAREMETERS HELP TO DESIGN THE CONTROL STRATEGIES: CONTROL ON-OFF (1) AND CONTROL PID (PROPORTIONAL?INTEGRAL?DERIVATIVE) (2). AS A RESULT WE OBTAIN THAT THE CONTROL PID MAINTAINS THE OBJECTS TEMPERATURE WITH MAJOR STABILITY THAN ON-OFF, WHAT MAKES IT PREFERABLE IN THE FINAL APPLICATION. THE FUTURE WORKS INVOLVE MODELING AMBIENTAL PERTURBATION, WHICH AFFECTS THE SYSTEM AND DETERMINATION THERMAL PARAMETERS OF THE ANTARCTIC PLANTS.

THIS PAPER PROPOSES A NEW COMMUNICATION PROTOCOL FOR OUTPUT-FEEDBACK CONTROL THROUGH MULTI-HOP WIRELESS SENSOR NETWORK (WSN). THE PROTOCOL IS BASED ON A HOP-BY-HOP TRANSPORT SCHEME AND IS ESPECIALLY DEVISED TO SIMULTANEOUSLY FULFILL TWO CONFLICTING CRITERIA: THE NETWORK ENERGY CONSUMPTION AND THE STABILITY/PERFORMANCE (IN TERMS OF H? NORM) OF THE CLOSED-LOOP SYSTEM. THE PROPOSED PROTOCOL CAN BE IMPLEMENTED BY MEANS OF THREE HEURISTICS, BASICALLY USING DISTINCT RULES TO CONTROL THE MAXIMUM NUMBER OF RETRANSMISSIONS ALLOWED IN TERMS OF THE VOLTAGE LEVEL OF THE BATTERIES OF THE NETWORK NODES. AS ANOTHER CONTRIBUTION, A MARKOV JUMP BASED REPRESENTATION IS PROPOSED TO MODEL THE PACKET LOSS IN THE COMMUNICATION CHANNEL, GIVING RISE TO A SYSTEMATIC PROCEDURE TO DETERMINE THE TRANSITION PROBABILITY MATRIX AND THE MARKOV CHAIN OPERATION MODES OF A NETWORK WITH MULTIPLE INFORMATION SOURCES. THE SYNTHESIS OF THE OUTPUT-FEEDBACK CONTROLLER IS MADE IN TWO STEPS (OBSERVER FILTER PLUS A STATE-FEEDBACK CONTROLLER) FOR THE MARKOV MODEL ASSUMING PARTIAL AVAILABILITY OF THE OPERATION MODES. THE EFFICIENCY AND APPLICABILITY OF THE COMMUNICATION PROTOCOL IS ILLUSTRATED BY MEANS OF A NUMERICAL EXPERIMENT, BASED ON A PHYSICAL MODEL OF A COUPLED TANKS PLANT. THE FEATURES OF EACH HEURISTIC OF IMPLEMENTATION OF THE PROPOSED PROTOCOL ARE PRESENTED IN THE NUMERICAL COMPARISONS.

THIS ARTICLE DOCUMENTS A CUSTOM SENSOR?ACTUATOR NETWORK DESIGNED AND IMPLEMENTED AS A PART OF EXPERIMENTAL SETUP, WHERE A LONG-TERM PHENOLOGICAL RESPONSE OF ANTARCTIC PLANTS IS STUDIED. THE FIRST PART OF OUR WORK PRESENTS THE CONTEXT OF THE STUDY, REPORTS EXPERIMENTAL METHODS USED IN ANTARCTIC PLANT FIELD STUDIES, AND CHARACTERIZES THE ENVIRONMENTAL CONDITIONS AND LOGISTICS FACILITIES AVAILABLE ON THE MEASUREMENT SPOT. AFTER CONTEXTUALIZATION OF THE RESEARCH, WE PRESENT, IN DETAIL, BOTH THE NETWORK ITSELF AND SOME RESULTS OBTAINED DURING THE ANTARCTIC SUMMER SEASONS BETWEEN 2019 AND 2022 ON THE KING GEORGE ISLAND, SOUTH SHETLANDS. THE RESULTS COLLECTED WITH OUR NETWORK AND CORRELATED WITH SELECTED DATA REGISTERED WITH A REFERENCE AUTOMATIC METEOROLOGICAL STATION REVEAL THE THERMAL PLANTS RESPONSE. THE GROUPS OF PLANTS INDIVIDUALS, WHICH WERE ACTIVELY WARMED USING THERMAL ACTUATORS, SHOW THE NIGHTTIME TEMPERATURE DIFFERENCE, IN REFERENCE TO THE AIR TEMPERATURE, OF 5 ?C, WHICH COMPLEMENTS THE DAYTIME DIFFERENCE CAUSED BY THE PASSIVE METHOD OF OPEN TOP CHAMBER (OTC) USED IN PREVIOUS STUDIES CARRIED OUT IN THE SAME LOCALIZATION.

WIRELESS TECHNOLOGIES HAVE ATTRACTED THE ATTENTION OF THE INDUSTRIAL SECTOR, DUE TO THEIR MULTIPLE ADVANTAGES SUCH AS EASE OF INSTALLATION, FLEXIBILITY AND MOBILITY. HOWEVER, THE APPLICATION OF WIRELESS IN INDUSTRY IS MOST LIMITED TO NON-CRITICAL SENSING APPLICATIONS, MAKING THE COMMUNICATION OF CRITICAL INSTRUMENTS AND CONTROL SYSTEMS ALMOST EXCLUSIVELY WITH WIRED MEDIA. DESPITE THIS, WIRELESS TECHNOLOGIES AND CONTROL TECHNIQUES ARE EVOLVING, STILL PRESENTING OPEN ISSUES AND CHALLENGES FOR ACADEMIA AND INDUSTRY, SO NEW SOLUTIONS AND STUDIES ARE REQUIRED. IN THIS PAPER, WE PRESENT OUR EXPERIENCES ON ENABLING WIRELESS CONTROL OF A COUPLED TANKS SYSTEM AVAILABLE AT THE UNIVERSITY OF THE BÍO-BÍO, CHILE. AS MOST OF THE EXISTING CONTROL SYSTEMS, SUCH A PLANT IS CONNECTED THROUGH ANALOG WIRED LINKS. WE CHANGED THIS BY INCORPORATING LOW-POWER WIRELESS MODULES FOR COMMUNICATING SENSOR AND CONTROL DATA. OUR FIRST RESULTS SHOW THAT, FOR THE CONSIDERED CASE STUDY, THE USE OF WIRELESS COMMUNICATIONS FOR CONTROL IS FEASIBLE, EVEN APPROACHING THE BEHAVIOR OF THE WIRED VERSION (WITH SOME RESTRICTIONS). THE IMPLEMENTATION WILL BE AVAILABLE REMOTELY FOR USE, ALLOWING PEOPLE FROM ALL OVER THE WORLD TESTING NEW APPROACHES IN WIRELESS NETWORKED CONTROL SYSTEMS.