Development and application of devices for GNSS signal jamming

Uz razvoj tehnologija pozicioniranja putem globalnih navigacijskih satelitskih sustava (GNSS), razvijale su se i tehnologije ometanja prijema signala odaslanih sa satelita. Tako su nastali ometači (eng. jammer) GNSS signala – radio-frekvencijski odašiljači dizajnirani tako da blokiranjem, prigušivanjem ili drugim načinima ometanja signala djelomično ili u potpunosti onemogućavaju određivanje položaja u prostoru. Iako je u velikom dijelu svijeta ometanje radijskih signala ilegalno, korištenje ometača sve je češće u civilnim i vojnim djelatnostima. U ovom radu prikazana je teorijska osnova tehnologija za ometanje signala te primjena jednostavnog uređaja kratkog dometa za ometanje signala GPS (Global Positioning System) satelita na više različitih GPS prijamnika. Dobiveni rezultati međusobno su uspoređeni te analizirani.Besides the development of the positioning technologies that use the Global Navigation Satellite Systems (GNSS), the GNSS jamming technologies were developed. Thus, the GNSS signal jammers were invented - RF transmitters designed to block, reduce or otherwise interfere signals and partially or completely disable GNSS positioning. Although, in many countries around the world RF jamming is illegal, the use of the jamming devices is not very rare in the civilian and military activities. This paper presents the theoretical basis of the signal jamming technology and the application of the simple short range GPS (Global Positioning System) jammer on several different GPS receivers. The results were compared and analyzed

Construction and calibration of a portable rain simulator designed for the in situ research of soil resistance to erosion

Land degradation caused by erosion processes is a widespread global problem. Rain simulators are one of the tools often used to determine the resistance of soils to erosion processes. The aim of this publication is to present the process of the construction and calibration of a small, portable field simulator which would be implemented in research studies designed to determine the changes in the soils’ shear strength parameters in forested areas (in situ) caused by a change in soil moisture content achieved by the rain simulation. The constructed simulator consists of a metal frame, sprayers (with specific nozzles), a sediment funnel/tray made of metal, water and a sediment collector unit, a water tank and pump, and a set of rubber hoses, manometer, valves, reducers, adapters and other supplementary equipment. The calibration was carried out by using the pluviometric method. The choice of nozzles was based on the criteria of low water consumption (losses), the Christiansen uniformity coefficient (CU) and the possibility of achieving specific downpour intensities for the investigated area. The further calibration of the device consisted of determining the raindrop diameter and the distribution of the rainfall when the simulator is positioned on the slopes (7° and 15°). The achieved rain intensity was 1.7–1.9 mm/min, with a CU of 92.23–93.70% for the raindrop diameters equal to 1.2 mm. The kinetic energy of the simulated rain (Ke) was 2.82∙10. The constructed simulator proved itself to be in accordance with all of the given criteria, and it can successfully be implemented in research studies aimed at determining the resistance of forest soils to erosion processes, infiltration, and sediment yield

The Amount of Weight Loss Six Months after Bariatric Surgery: It Makes a Difference

Background: Bariatric surgery, especially Roux-en-Y gastric bypass (RYGB), has become the most frequently used therapy for morbid obesity. Objectives: The aim of this study was to examine the effects of surgically induced weight loss on cardiopulmonary function 6 months after the procedure, as well as the effect of such an intervention on well-known risk factors for cardiovascular diseases. Methods: This is a cross-sectional study on 66 morbidly obese patients (BMI ≥40 or ≥35 kg/m2 with present comorbidities), comparing their cardiopulmonary function prior to and 6 months after RYGB surgery. Results: The substantial amount of weight loss (29.80 ± 13.27 kg) after RYGB surgery was associated with significant reduction of comorbidities, especially diabetes and sedentary lifestyle (p = 0.005 and p = 0.002, respectively). Regarding functional capacity, there was significant increase in peak oxygen uptake (VO2 peak, p = 0.003), duration of exercise testing, metabolic equivalents (exercise time and METs, p < 0.001), and in peak O2 pulse. These findings were particularly pronounced in a group of patients who had lost more than 18% of initial weight. Conclusions: Reduction of body weight after RYGB surgery is associated with significantly improved cardiorespiratory function 6 months after surgery, especially in patients who lost more than 18% of their initial body weight. In addition, substantial decreases in body weight were also associated with a reduction of cardiovascular risk factors such as diabetes, smoking, hypertriglyceridemia, and sedentary lifestyle

Structure of aesthetic experience

Cilj istraživanja bio je da se ispita veza estetskog doživljaja sa drugim dimenzijama subjektivnog doživljaja slika. Estetski doživljaj definisan je preko devet deskriptora izdvojenih na osnovu pregleda odgovarajuće literature: opčinjavajuće, neodljivo, jednistveno, neprolazno, duboko, izuzetno, univerzalno, neizrecivo, voleo/la bih da imam ovu sliku. Procene 24 slike na unipolarnim sedmočlanim skalama napravljenim od navedenih deskriptora analizirane su metodom glavnih komponenti. Dobijena je jedna glavna komponenta. Multipla regresija pokazala je da je estetski doživljaj, meren preko proseka procena na devet skala, veoma slabo povezan sa bazičnim dimenzijama subjektivnog doživljaja umetničkih slika, merenim preko instrumenta SDS 16. Faktor Pobuđenost bio je značajan prediktor estetskog doživljaja bez obzira na relativno mali procenat objašnjene varijanse. Predikcija ostalih faktora, Regularnost, Atraktivnost i Smirenost, nije bila značajna. Procene na SDS 16 preuzete su iz ranijeg istraživanja. Dalje regresione analize pokazale su da estetski doživljaj ima ulogu u proceni međusobne sličnosti-različitosti slika: mera estetskog doživljaja delimično objašnjava distribuciju slika u 2-D i 3-D prostoru MDS-a. Rezultati MDS-a preuzeti su iz ranijeg istraživanja. Na osnovu rezultata ovog istraživanja možemo zaključiti da se estetski doživljaj predstavlja jedinstven i relativno nezavistan fenomen.This study investigated the strructure of aesthetic experience and the relationship of this structure and other dimensions of the subjective judgements of paintings. Aesthetic experinece was defined by nine descriptors selected from relevant literature: fascinating, irresistible, unique, eternal, profound, exceptional, universal, unspeakable, I would like to have this painting. 24 paintings were judged of on nine unipolar seven-step scales that were made of the up-mentioned descriptors. The factor analysis extracted one principal component. Multiple regression has shown weak correlation between aesthetic expirience (averaged nine judgements) and the factors of the subjective judgements of paintings (the factors were measured by the instrument SDS 16; Radonjić & Marković, 2005). Factor Arousal was a significant predictor of aesthetic experience, but the percent of explained variance was relatively low (circa 23%). The prediction of other factors, Regularity, Atraction and Serenity, was not significant. For the purpose of this analysis we used the data from the previous study (Radonjić and Marković, 2005). Further regression analyses indicated the role of aesthetic experience in the similarity judgments of paintings: the distributions of the paintings within 2-D and 3-D MDS space were partially explained by the measure of aesthetic experience. The MDS data were taken from the previous study (Radonjić i Marković, 2004). The results of this study suggest that the aesthetic experience is a unique and relatively independent phenomenon: internally, it is not dividable into components, and externally, it is weakly correlated with the other subjective dimensions

Development and application of devices for GNSS signal jamming

Uz razvoj tehnologija pozicioniranja putem globalnih navigacijskih satelitskih sustava (GNSS), razvijale su se i tehnologije ometanja prijema signala odaslanih sa satelita. Tako su nastali ometači (eng. jammer) GNSS signala – radio-frekvencijski odašiljači dizajnirani tako da blokiranjem, prigušivanjem ili drugim načinima ometanja signala djelomično ili u potpunosti onemogućavaju određivanje položaja u prostoru. Iako je u velikom dijelu svijeta ometanje radijskih signala ilegalno, korištenje ometača sve je češće u civilnim i vojnim djelatnostima. U ovom radu prikazana je teorijska osnova tehnologija za ometanje signala te primjena jednostavnog uređaja kratkog dometa za ometanje signala GPS (Global Positioning System) satelita na više različitih GPS prijamnika. Dobiveni rezultati međusobno su uspoređeni te analizirani.Besides the development of the positioning technologies that use the Global Navigation Satellite Systems (GNSS), the GNSS jamming technologies were developed. Thus, the GNSS signal jammers were invented - RF transmitters designed to block, reduce or otherwise interfere signals and partially or completely disable GNSS positioning. Although, in many countries around the world RF jamming is illegal, the use of the jamming devices is not very rare in the civilian and military activities. This paper presents the theoretical basis of the signal jamming technology and the application of the simple short range GPS (Global Positioning System) jammer on several different GPS receivers. The results were compared and analyzed

Five-Year Outcomes in Bariatric Surgery Patients

Background and objectives: Obesity presents as a multifactorial, pandemic disease that arises as a consequence of unequal energy intake and energy consumption. Obesity adversely affects the quality of life, leading not only to disability, but also to various other disorders. Bariatric surgery is the most effective method for achieving significant and sustained weight loss in individuals with extreme obesity. The aim of this study was to examine how well surgically induced weight loss is maintained after five years of follow-up and its effects on cardiovascular risk factors and outcome. Materials and Methods: This is a retrospective cross-sectional study of 66 patients with morbid obesity, with body mass index (BMI) ≥ 40 kg/m2 or BMI ≥ 35 kg/m2 and obesity-related health conditions, aged 20 to 61 years, mostly women (77.3%) who underwent laparoscopic Roux-en-Y gastric bypass surgery. Results: Average follow-up was 6.42 years (95% CI 6.30–6.54 years) after surgery, with survival rate of 97% in operated individuals. There was a statistically significant reduction of weight and body mass index 6 months and 5 years after surgery in comparison to the initial values (p < 0.001). Of 62 patients who presented weight loss at the end of the follow-up period, 38 were able to maintain the amount of weight loss that was attained 6 months after surgery, while 24 patients regained weight compared to their postoperative weight at 6 months. Two patients reported no weight loss after treatment. Significant weight reduction was associated with better control of diabetes and increased self-reported physical activity at 6 months and 5 years after surgery, as well as with a reduction of the use of anti-diabetic and anti-hypertensive medications. Conclusions: Our research demonstrates a positive long-term impact of bariatric surgery on patients’ health conditions, significant and sustained weight loss, and decrease in BMI, which were associated with a reduction of co-morbidities and risk factors for cardiovascular diseases

Obesity and cardiology

Introduction: Morbid obesity is associated with a number of ventilatory and cardiovascular disorders and increased risk for cardiovascular diseases, which can be improved by weight loss. Cardiopulmonary testing (CPET) is proposed for the objective evaluation of the effects of bariatric surgery in morbid obese patients. Aim: To evaluate the change of CPET and hemodynamic parameters in patients treated with bariatric surgery. Methods: We performed CPET in 250 morbid obese patients during for the preoperative assessment. We analyzed 50 patients (37 women, mean age 38±10 years) before and 6 months after bariatric surgery. All patients underwent CPET (treadmill, Bruce protocol) with expiratory gas analyses. Results: The mean weight before treatment was 126.69 ±19.21kg, and BMI was 43.8 ± 5.4 kg/m2. Averaged body weight reduction was -29, 6 kg, and BMI -10 kg/m2 after 6 months follow-up, with significant difference in comparison to baseline values (43.8±5, 4 vs 33.9±14, 3; p<0.0001). CPET parameters showed increase in VO2 at ventilatory anaerobic threshold (17.86±3.44 vs 20.86±4.70; p<0.0001), Peak VO2 (20.79±3.63 vs 24.97±4.37; p<0.0001) and improvement of ventilatory efficacy VE/VCO2 slope (34.64±4.34 vs 24.74±3.39; p<0.0001), and PetCO confirming the improvement of cardiopulmonary function. Hemodynamic parameters were also improved with decrease in resting heart rate (p<0.0001), resting and peak systolic (p<0.0001) and diastolic blood pressure (p<0.0001 and p=0.002). Conclusion: These results show significant relationship between weight loss and improvement of anaerobic capacity after bariatric treatment. CPET is shown to be a valuable and reliable tool for the objective assessment of functional improvement

Open vs laparoscopic adrenalectomy for localized adrenocortical carcinoma

Objective: The purpose of the study was to compare the long-term outcomes of patients with localized adrenocortical carcinoma (ACC) subjected to open vs laparoscopic surgery. ----- Design: Retrospective study. ----- Patients: This retrospective study included 46 patients with the ACC ENSAT stage I-stage III of whom 23 underwent open surgery (OA group), whereas 23 were subjected to laparoscopic adrenalectomy (LA group). The main outcomes analysed in the study were differences between the OA and LA groups in recurrence-free survival (RFS) and overall survival (OS). ----- Results: Patients in OA group had larger tumours (120 [70-250] mm vs 75 [26-110] mm; P < .001), higher Ki-67 index (16 [1-65] % vs 10 [1-25] %; P = .04) and higher disease stage (P = .01) compared with the patients in the LA group. The median duration of follow-up for patients underwent OA and LA was 51 (12-174) and 53 (5-127) months, respectively. Eight patients (5 OA and 3 LA) experienced recurrent disease, whereas six patients (3 OA and 3 LA) died during follow-up. No differences in RFS and OS were found between patients who underwent open or laparoscopic surgery. ----- Conclusion: The study demonstrated that in patients with localized ACC and without invasion of extra-adrenal tissues, LA is a plausible treatment option in terms of RFS and OS. However, our results are limited to referral centres with large experience in the management of patients with ACC and may not necessarily apply to nonspecialized centres

Open vs laparoscopic adrenalectomy for localized adrenocortical carcinoma

Objective: The purpose of the study was to compare the long-term outcomes of patients with localized adrenocortical carcinoma (ACC) subjected to open vs laparoscopic surgery. ----- Design: Retrospective study. ----- Patients: This retrospective study included 46 patients with the ACC ENSAT stage I-stage III of whom 23 underwent open surgery (OA group), whereas 23 were subjected to laparoscopic adrenalectomy (LA group). The main outcomes analysed in the study were differences between the OA and LA groups in recurrence-free survival (RFS) and overall survival (OS). ----- Results: Patients in OA group had larger tumours (120 [70-250] mm vs 75 [26-110] mm; P < .001), higher Ki-67 index (16 [1-65] % vs 10 [1-25] %; P = .04) and higher disease stage (P = .01) compared with the patients in the LA group. The median duration of follow-up for patients underwent OA and LA was 51 (12-174) and 53 (5-127) months, respectively. Eight patients (5 OA and 3 LA) experienced recurrent disease, whereas six patients (3 OA and 3 LA) died during follow-up. No differences in RFS and OS were found between patients who underwent open or laparoscopic surgery. ----- Conclusion: The study demonstrated that in patients with localized ACC and without invasion of extra-adrenal tissues, LA is a plausible treatment option in terms of RFS and OS. However, our results are limited to referral centres with large experience in the management of patients with ACC and may not necessarily apply to nonspecialized centres