Modeling 2-D AR Processes With Various Regions of Support

Choi, ByoungSeon,Politis, Dimitris N. Institute of Electrical and Electronics Engineers 2007 IEEE transactions on signal processing Vol.55 No.5

<P>We show that there exists a causal 2-D linear process in the nonsymmetric half-plane having the same autocorrelations as a noncausal 2-D linear process in the whole-plane; this property is called the autocorrelation equivalence relation, and can be used for practical fitting and modeling of 2-D processes. Some causal 2-D autoregressive (AR) models with various regions of support are considered such as half-cross, half-diamond, quarter-plane square, half-square, half-hexagon, half-octagon, and half-circle. Considerations of parsimony in 2-D model fitting are then focused not only on the number of parameters in our model, but also most importantly on the optimal shape of the region of support. Their 2-D Yule-Walker equations are derived, and a computationally efficient order-recursive algorithm is proposed to solve them. The autocorrelation equivalence relation and the order-recursive algorithm are utilized to specify a noncausal 2-D AR process as well as its spectrum from a given realization of a random field</P>

Discussion: Bootstrap methods for dependent data: A review

Sílvia Gonçalves,Dimitris Politis 한국통계학회 2011 Journal of the Korean Statistical Society Vol.40 No.4

Accuracy and reliability of 2-dimensional photography versus 3-dimensional soft tissue imaging

Ayaz, Irem,Shaheen, Eman,Aly, Medhat,Shujaat, Sohaib,Gallo, Giulia,Coucke, Wim,Politis, Constantinus,Jacobs, Reinhilde Korean Academy of Oral and Maxillofacial Radiology 2020 Imaging Science in Dentistry Vol.50 No.1

Purpose: This study was conducted to objectively and subjectively compare the accuracy and reliability of 2-dimensional(2D) photography and 3-dimensional(3D) soft tissue imaging. Materials and Methods: Facial images of 50 volunteers(25 males, 25 females) were captured with a Nikon D800 2D camera (Nikon Corporation, Tokyo, Japan), 3D stereophotogrammetry (SPG), and laser scanning (LS). All subjects were imaged in a relaxed, closed-mouth position with a normal smile. The 2D images were then exported to Mirror^® Software (Canfield Scientific, Inc, NJ, USA) and the 3D images into Proplan CMF^® software (version 2.1, Materialise HQ, Leuven, Belgium) for further evaluation. For an objective evaluation, 2 observers identified soft tissue landmarks and performed linear measurements on subjects' faces (direct measurements) and both linear and angular measurements on all images(indirect measurements). For a qualitative analysis, 10 dental observers and an expert in facial imaging (subjective gold standard) completed a questionnaire regarding facial characteristics. The reliability of the quantitative data was evaluated using intraclass correlation coefficients, whereas the Fleiss kappa was calculated for qualitative data. Results: Linear and angular measurements carried out on 2D and 3D images showed excellent inter-observer and intra-observer reliability. The 2D photographs displayed the highest combined total error for linear measurements. SPG performed better than LS, with borderline significance (P=0.052). The qualitative assessment showed no significant differences among the 2D and 3D imaging modalities. Conclusion: SPG was found to a reliable and accurate tool for the morphological evaluation of soft tissue in comparison to 2D imaging and laser scanning.

Late reconstruction of extensive orbital floor fracture with a patient-specific implant in a bombing victim

Maximiliaan Smeets,Robin Snel,Yi Sun,Titiaan Dormaar,Constantinus Politis 대한구강악안면외과학회 2020 대한구강악안면외과학회지 Vol.46 No.5

Fractures of the orbital floor and walls are among the most frequent maxillofacial fractures. Virtual three-dimensional (3D) planning and use of patientspecific implants (PSIs) could improve anatomic and functional outcomes in orbital reconstruction surgery. The presented case was a victim of a terrorist attack involving improvised explosive devices. This 58-year-old female suffered severe wounds caused by a single piece of metal from a bomb, shattering the left orbital floor and lateral orbital wall. Due to remaining hypotropia of the left eye compared to the right eye, late orbital floor reconstruction was carried out with a personalised 3D printed titanium implant. We concluded that this technique with PSI appears to be a viable method to correct complex orbital floor defects. Our research group noted good aesthetic and functional results one year after surgery. Due to the complexity of the surgery for a major bony defect of the orbital floor, it is important that the surgery be executed by experienced surgeons in the field of maxillofacial traumatology.

A systematic review of treatment and outcomes in patients with mandibular coronoid process hyperplasia

Griet I.L. Parmentier,Margaux Nys,Laurence Verstraete,Constantinus Politis 대한구강악안면외과학회 2022 대한구강악안면외과학회지 Vol.48 No.3

Treatment of mandibular coronoid process hyperplasia (MCPH) has been described and explored in the literature. This systematic review aims to provide a comprehensive overview of the surgical and non-surgical treatment options for MCPH in pediatric and adult populations. Three databases were searched for treatment of MCPH patients (MEDLINE, Embase, and Web of Science). Two reviewers selected case reports and case series based on titles and abstracts. Finally, 55 studies reporting a total of 127 cases were included for qualitative synthesis and data extraction. The mean age at symptom onset was 15.6 years, while the mean age at diagnosis was 23.5 years. Of the included cases, 83.7% were male, and the condition was bilateral in more than 81% of the cases. Coronoidectomy was performed in 82.7% of the included cases, while coronoidotomy was performed in 3.9% of the cases. In 85.0% of the surgically treated cases, the approach was intraoral. The mean maximal intraoperative mouth opening was 38.1 mm compared with 16.5 mm at diagnosis. The mean maximal postoperative mouth opening was 35.3 mm, and the mean follow-up period was 16.3 months. Maximum mouth opening was achieved intraoperatively, and non-surgical treatment after surgery aims to reduce the risk of relapse. Additional research with a higher level of evidence is necessary to confirm these findings.

Accuracy and reliability of 2-dimensional photography versus 3-dimensional soft tissue imaging

Irem Ayaz,Eman Shaheen,Medhat Aly,Sohaib Shujaat,Giulia Gallo,Wim Coucke,Constantinus Politis,Reinhilde Jacobs 대한영상치의학회 2020 Imaging Science in Dentistry Vol.50 No.1

Purpose: This study was conducted to objectively and subjectively compare the accuracy and reliability of 2-dimensional (2D) photography and 3-dimensional (3D) soft tissue imaging. Materials and Methods: Facial images of 50 volunteers (25 males, 25 females) were captured with a Nikon D800 2D camera (Nikon Corporation, Tokyo, Japan), 3D stereophotogrammetry (SPG), and laser scanning (LS). All subjects were imaged in a relaxed, closed-mouth position with a normal smile. The 2D images were then exported to Mirror® Software (Canfield Scientific, Inc, NJ, USA) and the 3D images into Proplan CMF® software (version 2.1, Materialise HQ, Leuven, Belgium) for further evaluation. For an objective evaluation, 2 observers identified soft tissue landmarks and performed linear measurements on subjects’ faces (direct measurements) and both linear and angular measurements on all images (indirect measurements). For a qualitative analysis, 10 dental observers and an expert in facial imaging (subjective gold standard) completed a questionnaire regarding facial characteristics. The reliability of the quantitative data was evaluated using intraclass correlation coefficients, whereas the Fleiss kappa was calculated for qualitative data. Results: Linear and angular measurements carried out on 2D and 3D images showed excellent inter-observer and intra-observer reliability. The 2D photographs displayed the highest combined total error for linear measurements. SPG performed better than LS, with borderline significance (P=0.052). The qualitative assessment showed no significant differences among the 2D and 3D imaging modalities. Conclusion: SPG was found to a reliable and accurate tool for the morphological evaluation of soft tissue in comparison to 2D imaging and laser scanning.

In vivo quantification of mandibular bone remodeling and vascular changes in a Wistar rat model: A novel HR-MRI and micro-CT fusion technique

Dandan Song,Sohaib Shujaat,Ruiting Zhao,Yan Huang,Eman Shaheen,Jeroen Van Dessel,Kaan Orhan,Greetje Vande Velde,Ruxandra Coropciuc,Ruben Pauwels,Constantinus Politis,Reinhilde Jacobs 대한영상치의학회 2020 Imaging Science in Dentistry Vol.50 No.3

Purpose: This study was performed to introduce an in vivo hybrid multimodality technique involving the coregistration of micro-computed tomography (micro-CT) and high-resolution magnetic resonance imaging (HR-MRI) to concomitantly visualize and quantify mineralization and vascularization at follow-up in a rat model. Materials and Methods: Three adult female rats were randomly assigned as test subjects, with 1 rat serving as a control subject. For 20 weeks, the test rats received a weekly intravenous injection of 30 μg/kg zoledronic acid, and the control rat was administered a similar dose of normal saline. Bilateral extraction of the lower first and second molars was performed after 10 weeks. All rats were scanned once every 4 weeks with both micro-CT and HR-MRI. Micro-CT and HR-MRI images were registered and fused in the same 3-dimensional region to quantify blood flow velocity and trabecular bone thickness at T0 (baseline), T4 (4 weeks), T8 (8 weeks), T12 (12 weeks), T16 (16 weeks), and T20 (20 weeks). Histological assessment was the gold standard with which the findings were compared. Results: The histomorphometric images at T20 aligned with the HR-MRI findings, with both test and control rats demonstrating reduced trabecular bone vasculature and blood vessel density. The micro-CT findings were also consistent with the histomorphometric changes, which revealed that the test rats had thicker trabecular bone and smaller marrow spaces than the control rat. Conclusion: The combination of micro-CT and HR-MRI may be considered a powerful non-invasive novel technique for the longitudinal quantification of localized mineralization and vascularization

Influence of Seasonal Forcing on Habitat Use by Bottlenose Dolphins Tursiops truncatus in the Northern Adriatic Sea

Bearzi, Giovanni,Azzellino, Arianna,Politi, Elena,Costa, Marina,Bastianini, Mauro The Korean Society of Oceanography 2008 Ocean science journal Vol.43 No.4

Bottlenose dolphins are the only cetaceans regularly observed in the northern Adriatic Sea, but they survive at low densities and are exposed to significant threats. This study investigates some of the factors that influence habitat use by the animals in a largely homogeneous environment by combining dolphin data with hydrological and physiographical variables sampled from oceanographic ships. Surveys were conducted year-round between 2003 and 2006, totalling 3,397 km of effort. Habitat modelling based on a binary stepwise logistic regression analysis predicted between 81% and 93% of the cells where animals were present. Seven environmental covariates were important predictors: oxygen saturation, water temperature, density anomaly, gradient of density anomaly, turbidity, distance from the nearest coast and bottom depth. The model selected consistent predictors in spring and summer. However, the relationship (inverse or direct) between each predictor and dolphin presence varied among seasons, and different predictors were selected in fall. This suggests that dolphin distribution changed depending on seasonal forcing. As the study area is relatively uniform in terms of bottom topography, habitat use by the animals seems to depend on complex interactions among hydrological variables, caused primarily by seasonal change and likely to determine shifts in prey distribution.

Influence of Seasonal Forcing on Habitat Use by Bottlenose Dolphins Tursiops truncatus in the Northern Adriatic Sea

Giovanni Bearzi,Arianna Azzellino,Elena Politi,Marina Costa,Mauro Bastianini 한국해양과학기술원 2008 Ocean science journal Vol.43 No.4

Bottlenose dolphins are the only cetaceans regularly observed in the northern Adriatic Sea, but they survive at low densities and are exposed to significant threats. This study investigates some of the factors that influence habitat use by the animals in a largely homogeneous environment by combining dolphin data with hydrological and physiographical variables sampled from oceanographic ships. Surveys were conducted year-round between 2003 and 2006, totalling 3,397 km of effort. Habitat modelling based on a binary stepwise logistic regression analysis predicted between 81% and 93% of the cells where animals were present. Seven environmental covariates were important predictors: oxygen saturation, water temperature, density anomaly, gradient of density anomaly, turbidity, distance from the nearest coast and bottom depth. The model selected consistent predictors in spring and summer. However, the relationship (inverse or direct) between each predictor and dolphin presence varied among seasons, and different predictors were selected in fall. This suggests that dolphin distribution changed depending on seasonal forcing. As the study area is relatively uniform in terms of bottom topography, habitat use by the animals seems to depend on complex interactions among hydrological variables, caused primarily by seasonal change and likely to determine shifts in prey distribution. Bottlenose dolphins are the only cetaceans regularly observed in the northern Adriatic Sea, but they survive at low densities and are exposed to significant threats. This study investigates some of the factors that influence habitat use by the animals in a largely homogeneous environment by combining dolphin data with hydrological and physiographical variables sampled from oceanographic ships. Surveys were conducted year-round between 2003 and 2006, totalling 3,397 km of effort. Habitat modelling based on a binary stepwise logistic regression analysis predicted between 81% and 93% of the cells where animals were present. Seven environmental covariates were important predictors: oxygen saturation, water temperature, density anomaly, gradient of density anomaly, turbidity, distance from the nearest coast and bottom depth. The model selected consistent predictors in spring and summer. However, the relationship (inverse or direct) between each predictor and dolphin presence varied among seasons, and different predictors were selected in fall. This suggests that dolphin distribution changed depending on seasonal forcing. As the study area is relatively uniform in terms of bottom topography, habitat use by the animals seems to depend on complex interactions among hydrological variables, caused primarily by seasonal change and likely to determine shifts in prey distribution.

No Effect of Serotoninergic Gene Variants on Response to Interpersonal Counseling and Antidepressants in Major Depression

Alessandro Serretti,Chiara Fabbri,Silvia Pellegrini,Stefano Porcelli,Pierluigi Politi,Silvio Bellino,Marco Menchetti,Veronica Mariotti,Cristina Demi,Valentina Martinelli,Marco Cappucciati,Paola Bozzat 대한신경정신의학회 2013 PSYCHIATRY INVESTIGATION Vol.10 No.2

Objective-Gene variants within the serotonin pathway have been associated with major depressive disorder (MDD) treatment outcomes, however a possible different modulation on pharmacological or psychological treatments has never been investigated. Methods-One hundred sixty MDD patients were partially randomized to either inter-personal counseling (IPC) or antidepressants. The primary outcome was remission at week 8. Five serotonergic polymorphisms were investigated (COMT rs4680, HTR1A rs6295, HTR2A rs2224721, HTR2A rs7997012 and SLC6A4 rs421417). Results-IPC (n=43) and antidepressant (n=117) treated patients did not show any difference in remission rates at week 8 (corrected for baseline severity, age and center). None of the studied gene variants impacted on response and remission rates at week 8 neither in the IPC nor in the antidepressant group. An analysis of the whole sample showed a trend of association between rs7997012 AA genotype and a better treatment outcome. Conclusion-Our study confirms that IPC is an effective psychological intervention comparable to antidepressants in mild-moderate MDD. Polymorphisms related to the serotonin system did not exert a major effect on clinical outcomes in none of the treatment groups.