This paper presents a compact multifrequency reconfigurable patch antenna in terms of design and fabrication for operating in the S and C bands of the RF spectrum, which are overwhelmed by wireless applications. Reconfiguration is achieved by using a single PIN diode on the ground plane. By varying the voltage applied to the diode, three modes can emerge, exhibiting main resonant frequencies at 2.07, 4.63, and 6.22 GHz. Resonance switching requires a voltage of less than 0.9 V. The antenna fabricated on an FR-4 substrate, with a volume of 70 × 60 × 1.5 mm³, has a radiating patch element of a rectangular ring shape. The proposed low-cost antenna is easily implemented in a typical university lab-based environment. The total bandwidth for the three modes is close to 1 GHz, while the voltage standing wave ratio (VSWR) of the fabricated version of the antenna does not exceed 1.02, and the return loss is well below −40 dB for the three primary resonant frequencies.

Schumann resonance oscillation detection is a complex procedure which requires customized and high-quality measurement systems. The primary objective of this work was to design and implement a stand-alone, portable, and low-cost receiver able to measure as much Schumann resonance harmonics as possible. Design, as well as detailed analysis of the efficient induction coil magnetic antenna and the low-noise amplifying-filtering chain, is presented. The detection system includes two coils back to back, resulting in a total coil length of 60 cm. The filtering and amplification chain exhibits an experimentally measured total passband gain equal to 112 dB at 10 Hz and as low as 2.88 nV/√Hz equivalent input noise. In order to validate the new portable ELF Schumann resonance detection and monitoring system, we took measurements at various spots “relatively” free from man-made electromagnetic pollution. Results have shown very clear Schumann resonance peaks for the first six modes with 10-min acquisition time.

Green buildings not only operate as energy-efficient structures but are also enriched with various sensors and network-supported environments. These are capable of sustaining high indoor environmental quality. This paper presents a simplified deterministic simulation framework and an extended simulation scenario for assessing how IoT-monitored green buildings may reduce indoor environmental risk for occupants with chronic health vulnerabilities. The model is motivated by previous work on green residences, housing conditions, and their relationship to physical and psychological health, where indoor air quality, ventilation, thermal comfort, humidity, noise, lighting, dust, chemical exposure, and smoke are treated as relevant housing-related factors. A baseline simulation with a virtual duration of 100 days was conducted using 100 code-generated participants distributed across two building categories: a bad climate house (BCH) and a green monitored house (GMH). Three chronic-condition profiles were taken into consideration: asthma, chronic obstructive pulmonary disease, and anxiety/stress. This prototype version of the developed Octave-compatible code allows the baseline behavior of the proposed risk model to be examined directly. The simulation protocol included nine indoor environmental indicators and a normalized risk score ranging from 0 to 100, with values classified as low, moderate, or high risk. An extended simulation was then introduced to examine a broader scenario. This extension added a normal house (NH) as an intermediate building category and expanded the health-condition set from three to five assigned profiles by including allergies and depression/low well-being. Controlled building-profile and health-profile deviations were also included, while allergies and depression/low well-being were parameterized with building-specific coefficients. This allowed the model to examine not only the separation between the two extreme cases but also the intermediate role of a partially controlled building scenario. The results showed a clear difference in risk response between the building categories. In the basic scenario, the BCH produced high final risk scores, whereas the GMH achieved low final risk scores. At the building level, the final mean risk was approximately 100.00 for the BCH and 9.37 for the GMH. In the extended simulation, the aggregated final mean risk was 99.08 for the BCH, 44.95 for the NH, and 9.02 for the GMH. These results show a clear building-level risk stratification, i.e., high risk for the adverse building case, moderate risk for the intermediate building case, and low risk for the green monitored building case. These findings should be interpreted as deterministic and extended simulation results under predefined normalized environmental profiles, not as direct clinical or field validation. The proposed code strategy is not intended as a clinical diagnostic tool, but as an oriented modeling approach for future IoT-based green building assessment, digital twin integration, and risk-aware environment management.

In the modern technological era of sophisticated applications and high-quality communications, a platform of clever strategy and quickly updated systems is needed. It should be capable of withstanding the fastest emerging problems like signal attenuation and hostile actions intended to harm the whole network. The main contributions of this work are the production of an OFDM system (with low cost) that can sustain high-speed communications and be easily adjusted with new integrated code while exhibiting the feasibility of implementing a transmitter–receiver system in the same DSP and demonstrating the holistic approach with the qualitative integration of such an architecture in a warfare scenario. Specifically, in this research, the point of view is toward three facts. The first is to show a method of quick self-checking the operational status of a digital signal processor (DSP) platform and then the pedagogical issues of how to fast check and implement an updated code inside DSPs through simple schematics. The second point is to present the prototype system that can easily be programmed using a graphical user interface (GUI) and can change its properties (such as the transmitted modulated sinusoids—orthogonal frequency division multiplexing subcarriers). Alongside the presentation, the measurements are presented and discussed. These were acquired with the use of an oscilloscope and spectrum analyzer. The third point is to qualitatively show the application of such a system inside a modern warfare environment and to recommend various potential system responses according to the development of such a platform of reconfigurable implemented OFDM systems. The implementation was performed for two types of systems: (1) transmitter and (2) transmitter–receiver system. Notably, the system acts quickly with a delay of about 1 msec in the case of transmitting and receiving in the same DSP, suggesting excellent future results under real conditions.

Voice disorders often remain undiagnosed. Many self-perceived questionnaires exist for various medical conditions. Here, we used the Greek Voice Handicap Index (VHI) to address the aforementioned problem. Everyone can fill in the VHI questionnaire and rate their symptoms easily. The innovative feature of this research is the global cut-off score calculated for the VHI. Therefore, the VHI is now capable of helping clinicians establish a more customizable treatment plan with the cut-off point identifying patients without normal phonation. For the purpose of finding the global cut-off point, a group of 180 participants was recruited in Greece (90 non-dysphonic participants and 90 with different types of dysphonia). The voice disordered group had higher VHI scores than those of the control group. In contrast to previous studies, we provided and validated for the first time the cut-off points for all VHI domains and, finally, a global cut-off point through ROC and precision-recall analysis in a voice disordered population. In practice, a score higher than the well-estimated global score indicates (without intervention) a possible voice disorder. Nevertheless, if the score is near the threshold, then the patient should definitely follow preventive measures.