Flexible and Reconfigurable OFDM Implementation in DSP Platform for Various Purposes and Applications.

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.

A Frequency-Selective Reconfigurable Antenna for Wireless Applications in the S and C Bands.

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.

New Results for the Error Rate Performance of LoRa Systems over Fading Channels.

Long Range (LoRa) systems have recently attracted significant attention within the research community as well as for commercial use due to their ability to transmit data over long distances at a relatively low energy cost. In this study, new results for the bit error rate performance of Long Range (LoRa) systems operating in the presence of Rayleigh, Rice, Nakagami-m, Hoyt, η-µ and generalized fading channels are presented. Specifically, we propose novel exact single integral expressions as well as simple, accurate expressions that yield tight results in the entire signal-to-noise ratio (SNR) region. The validity of our newly derived formulas is substantiated by comparing numerically evaluated results with equivalent ones, obtained using Monte-Carlo simulations and exact analytical expressions.

ROC Analysis Cut-off Points of Hellenic Voice Handicap Index for Neurogenic Voice Disorders Patients: an Exploratory Study.

OBJECTIVE: The inclusion of subjective methods for evaluating Voice Disorders is proven an essential factor for diagnosis as these methods include self-reported questionnaires (eg, Voice Handicap Index-VHI) for everyday clinical practice. In turn, by obtaining cut-off scores of self-perceived questionnaires intended for assessment procedures of different voice disorders (eg, patients with neurological problems), the clinicians might be helped toward finding their patients' needs leading to better monitoring, and treatment suggestions. Consequently, the purpose of this study was to estimate the cut-off scores for the Greek VHI relevant to patients with neurogenic voice disorders. METHODS: Ninety subjects participated in this research. Sixty-six of them served as the control group while the remaining 24 patients exhibited Neurogenic Voice Disorders (eg, spasmodic dysphonia or vocal fold paralysis). They filled in the VHI and the Voice Evaluation Template. All participants were examined with the use of video laryngeal endoscopy and stroboscopy. RESULTS: The analysis revealed higher medians in all domains (of the VHI) for the patients compared to the control group. The cut-off points were estimated at the values of 24.50 (Total Score-AUC 0.932, P = 0.000), 9.00 (Functional Domain-AUC 0.917, P = 0.000), 10.00 (Physical Domain-AUC 0.948, P = 0.000), and 9.00 (Emotional Domain-AUC 0.830, P = 0.000). CONCLUSION: The estimated cut-off scores are in agreement with previous studies. These scores could probably used to enhance therapeutic monitoring of patients who suffer from neurogenic voice disorders. This study underlines the importance of considering different cutoff points for individuals with voice disorders due to diverse neurogenic etiologies.

Lexical Diversity in Cypriot-Greek-Speaking Toddlers: A Preliminary Longitudinal Study.

BACKGROUND/AIMS: The number of different words (NDW), an essential measure of lexical diversity, is extremely valuable towards providing data regarding children's language development. However, in Cyprus, practitioners are deprived of the opportunity to utilize NDW, as no normative data exist for toddlers who speak Cypriot Greek (CYG). METHODS: The language samples of 36 monolingual CYG-speaking toddlers (aged 36, 40, 44, and 48 months) with a typical course of language development were collected and quantitatively analyzed. Based on the language sample analysis, we ascertained typical NDW values at the aforementioned ages and tested through a linear mixed-effects model whether gender and age affected NDW. RESULTS: The results showed that age significantly predicted NDW increase; gender did not emerge as a significant predictor of NDW, but this may be due to the small statistical power. CONCLUSION: This study intends to provide the first step towards longitudinal investigation of the level of NDW for CYG-speaking children with a typical course of language development. The provided data, which could serve as preliminary norms, may be used - under some restrictions for the time being - during language assessment. Moreover, these acquired data could contribute to the development of an NDW database for diverse CYG-speaking populations of different age ranges in the future.

The Hellenic Voice Handicap Index of Different Laryngeal Mass Lesions: A Receiver-Operating Characteristic Analysis.

BACKGROUND: Voice disorders influence the quality of people's life. When the type of disorder is determined then the clinicians are capable of finding their patients' needs and address their complaints concerning their vocal problems. One of the most used tools, for assessing the patients' quality of life (in accordance with their vocal status), is the Voice Handicap Index. In this study, we determined the cut-off scores of Voice Handicap Index for population with laryngeal mass lesions such as vocal polyps and nodules. The calculated cut-off points further guide clinicians toward applying a needed interventional method/therapy even in the cases where the condition of a person could not be easily estimated. METHODS: The study involved 130 participants (aged 19-74). Specifically, 90 nondysphonic people served as the control group, while 40 participants had already been diagnosed with voice disorders due to laryngeal mass lesions. Participants who were diagnosed with a laryngeal inflammation or had undergone a surgery were excluded from the study. The cut-off scores were determined through a receiver-operating characteristic (ROC) analysis. RESULTS: The calculated cut-off points were 19.50 for the total score of VHI, 7.50 for the functional domain, and 8.50 for the physical and the emotional domain. CONCLUSIONS: The aforementioned cut-off points could be used in empowering the everyday clinical practice. Moreover, their knowledge could help the construction of an individualized therapy plan, as well as monitoring-biofeedback tool for the populations with vocal fold lesions.

Cross-cultural Adaptation and Validation of the Greek Voice Handicap Index-10 (GVHI-10) With Additional Receiver Operating Characteristic Analysis.

OBJECTIVE(S): The use of subjective evaluation tools are proven useful and of high clinical value in the case of voice disordered population. For that type of evaluation, self-assessment questionnaires about the severity of the voice like Voice Handicap Index-30 (VHI-30) have been developed. The VHI-30 is the most studied tool which includes psychometrically robustness while guiding physician's therapeutic decision making. Additionally, a valid abbreviated version of VHI-30 was developed for the first time in the Greek Language which is named as Greek Voice Handicap Index-10 (GVHI-10). Consequently, the aim of our study was to validate the proposed version of the VHI-10. METHODS: Ninety nondysphonic individuals and 90 dysphonic patients were classified by Otolaryngologists and Speech Language Pathologists. The study's subjects were evaluated with endoscopy and stroboscopy. Also, they were administrated the GVHI-30 and the translated version of the Voice Evaluation Template (VEF). The GVHI-10 was extracted by the Greek version of VHI-30. RESULTS: The group with voice disorders exhibited higher statistical significance in all GVHI-10 scores compared to those of the control group. The GVHI-10 showed a high internal consistency (Cronbach's a = 0.915 and split-half reliability coefficient equal to 0.86), good sensitivity compared to Greek VHI-30 (r = 0.764, P = 0.000) and intraclass correlation. A total cut-off point equal to 6.50 (AUC: 0.964; P < 0.001) was also calculated. CONCLUSIONS: The proposed version of GVHI-10 distinguished the perceived levels of voice between dysphonic and nondysphonic groups and between different voice disordered populations. The GVHI-10 is shown to be clinically valid and sensitive exhibiting high reliability.

Checking for voice disorders without clinical intervention: The Greek and global VHI thresholds for voice disordered patients.

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.

Voice Handicap Index and Interpretation of the Cutoff Points Using Receiver Operating Characteristic Curve as Screening for Young Adult Female Smokers.

The relationship between smoking and alterations of the vocal tract and larynx is well known. This pathology leads to the degradation of voice performance in daily living. Multiple assessment methods of vocal tract and larynx have been developed, and in recent years they were enriched with self-reported questionnaires such as Voice Handicap Index (VHI). This study determined the cutoff points of VHI's total score and its three domains for young female smokers in Greece. These estimated cutoff points could be used by voice specialists as an indicator for further clinical evaluation (foreseeing a potential risk of developing a vocal symptom because of smoking habits). A sample of 120 female nondysphonic smokers (aged 18-31) was recruited. Participants filled out the VHI and Voice Evaluation Form. VHI's cutoff point of total score was calculated at the value of 19.50 (sensitivity: 0.780, 1-specificity: 0.133). Specifically, the construct domain of functional was 7.50 (sensitivity: 0.900, 1-specificity: 0.217), for physical it was 8.50 (sensitivity: 0.867, 1-specificity: 0.483), and for emotional it was 7.50 (sensitivity: 0.833, 1-specificity: 0.200) through the use of receiver operating characteristic. Furthermore, VHI could be used as a monitoring tool for smokers and as a feedback for smoking cessation.

Using Receiver Operating Characteristic Curve to Define the Cutoff Points of Voice Handicap Index Applied to Young Adult Male Smokers.

Voice performance is an inextricable key factor of everyday life. Obviously, the deterioration of voice quality can cause various problems to human communication and can therefore reduce the performance of social skills (relevant to voice). The deterioration could be originated from changes inside the system of the vocal tract and larynx. Various prognostic methods exist, and among them is the Voice Handicap Index (VHI). This tool includes self-reported questionnaires, used for determining the cutoff points of total score and of its three domains relevant to young male Greek smokers. The interpretation of the calculated cutoff points can serve as a strong indicator of imminent or future evaluation by a clinician. Consistent with previous calculation, the VHI can also act as a feedback for smokers' voice condition and as monitoring procedure toward smoking cessation. Specifically, the sample consisted of 130 male nondysphonic smokers (aged 18-33 years) who all participated in the VHI test procedure. The test results (through receiver operating characteristic analysis) concluded to a total cutoff point score of 19.50 (sensitivity: 0.838, 1-specificity: 0). Also, in terms of constructs, the Functional domain was equal to 7.50 (sensitivity: 0.676, 1-specificity: 0.032), the Physical domain was equal to 7.50 (sensitivity: 0.706, 1-specificity: 0.032), and the Emotional domain was equal to 6.50 (sensitivity: 0.809, 1-specificity: 0.048).

Acoustic and Perceived Measurements Certifying Tango as Voice Treatment Method.

Voice disorders are affecting everyday life in many levels, and their prevalence has been studied extensively in certain and general populations. Notably, several factors have a cohesive influence on voice disorders and voice characteristics. Several studies report that health and environmental and psychological etiologies can serve as risk factors for voice disorders. Many diagnostic protocols, in the literature, evaluate voice and its parameters leading to direct or indirect treatment intervention. This study was designed to examine the effect of tango on adult acoustic voice parameters. Fifty-two adults (26 male and 26 female) were recruited and divided into four subgroups (male dancers, female dancers, male nondancers, and female nondancers). The participants were asked to answer two questionnaires (Voice Handicap Index and Voice Evaluation Form), and their voices were recorded before and after the tango dance session. Moreover, water consumption was investigated. The study's results indicated that the voices' acoustic characteristics were different between tango dancers and the control group. The beneficial results are far from prominent as they prove that tango dance can serve stand-alone as voice therapy without the need for hydration. Also, more research is imperative to be conducted on a longitudinal basis to obtain a more accurate result on the required time for the proposed therapy.

Comparison of Voice Handicap Index Scores Between Female Students of Speech Therapy and Other Health Professions.

Students' groups (eg, teachers, speech language pathologists) are presumably at risk of developing a voice disorder due to misuse of their voice, which will affect their way of living. Multidisciplinary voice assessment of student populations is currently spread widely along with the use of self-reported questionnaires. This study compared the Voice Handicap Index domains and item scores between female students of speech and language therapy and of other health professions in Greece. We also examined the probability of speech language therapy students developing any vocal symptom. Two hundred female non-dysphonic students (aged 18-31) were recruited. Participants answered the Voice Evaluation Form and the Greek adaptation of the Voice Handicap Index. Significant differences were observed between the two groups (students of speech therapy and other health professions) through Voice Handicap Index (total score, functional and physical domains), excluding the emotional domain. Furthermore, significant differences for specific Voice Handicap Index items, between subgroups, were observed. In conclusion, speech language therapy students had higher Voice Handicap Index scores, which probably could be an indicator for avoiding profession-related dysphonia at a later stage. Also, Voice Handicap Index could be at a first glance an assessment tool for the recognition of potential voice disorder development in students. In turn, the results could be used for indirect therapy approaches, such as providing methods for maintaining vocal health in different student populations.