Mustafa Eren Yildirim

Execution Time Prediction for 3D Interactive CAPTCHA by Keystroke Level Model

CAPTCHA is a standard defense system which stands for Completely Automated Public Turing test to tell Computers and Human Apart. The basic idea of CAPCHA is providing questions that human users can easily recognize and answer but computer programs cannot. In this study, an interactive 3D CAPTCHA was introduced, and developed for better security. The design and evaluation phases are presented in detail. The proposed model passed the necessary security tests. The Keystroke Level Model (KLM) can be used to evaluate and predict task execution time for a specific system usage scenario. KLM is based on calculation on the sequences of the users’ tasks or actions. This study attempts to estimate execution times for 3D animated CAPTCHA by KLM. An interactive CAPTCHA method is developed by Flash Movie Technology which is used commonly in the web sites. The results show that performing the 3D CAPTCHA requires a serious amount of time. New interaction methods should be considered to improve the users’ performance.

A user study: the effects of mobile phone prototypes and task complexities on usability

Mobile phones are increasingly becoming ubiquitous computational devices that are almost always available, individually adaptable, and nearly universally connectable (using both wide area and short range communication capabilities). Up to now, mobile phones have been used in purpose of the fact that we can send SMS messages among each other, save our important notes, save our schedules; connect to internet and so on. But how much can a mobile phone simplify our everyday interactions, before it itself becomes a usability burden? What are the capabilities and limitations of using mobile phones with different prototypes and complexities of the interaction items in itself. This paper presents a user study investigating the use of a prototypical, mobile phone based interaction system to send text messages and save schedules classified as simple and complex task settings. Our results show that mobile devices can greatly simplify our usage by using computer type prototypes with complex task settings. We have studied the effect of prototype of mobile phone and complexity of task for the usability test on subjective user evaluation. In this experiment, mobile phones with special software were given to test users (N=60) for a period of a week. Prototype design was done by using different kinds of platforms such as: paper, computer, and a fully operational appliance and also complexity of task was chosen as sending message and editing a saved schedule with the mobile phone, simple and complex task respectively. Later, a subjective user evaluation was measured in 5 points scale. Experiment results yielded that computer type prototype has significantly higher usability rate than paper type prototype and there is a significant interaction between prototype and complexity. Eventually, computer type prototype with complex task yielded highest rate while paper type prototype with simple task yielded lowest usability rates.

Gender Recognition using Hog with Maximized Inter-Class Difference

Several methods and features have been proposed for gender recognition problem. Histogram of oriented gradients (Hog) is a widely used feature in image processing. This study proposes a gender recognition method using full body features. Human body from side and front view were represented by Hog. Using all bins in the histogram requires longer time for training. In order to decrease the computation time, descriptor size should be decreased. Inter-class difference was obtained as a vector and sorted in a descending order. The bins with the largest value were selected among this vector. Random forest and Adaboost methods were used for the recognition. As a result of both tests, the classifier using first 100 bins with maximum difference gives the optimum performance in terms of accuracy rate and computation time. Although Adaboost performed faster, the accuracy of random forest is higher in full body gender recognition.

Prognostic Significance of Indicators of Systemic Inflammatory Responses in Glioblastoma Patients

Background: High-grade gliomas, with glioblastomas as the most frequently observed histologic subtype, are the most common primary brain tumours in adults. It is considered that inflammatory responses play a major role in malignancies, including tumour progression. This study aimed to determine the prognostic significance of the neutrophil to lymphocyte ratio (NLR) and the thrombocyte to lymphocyte ratio (PLR) as indicators of systemic inflammatory response (SIR) in glioblastoma patients. Methods: A total of 90 patients treated for glioblastoma were retrospectively evaluated. Absolute counts were used to generate NLR and PLR. A SIR was considered to be present with an NLR ≥5 and/or PLR ≥150. Results: Median follow-up time was 11.3 months (range: 1-70 months). The 1-year and 2-year overall survival rates were 55.2% and 19.5%, respectively. Univariate analysis showed that there was no correlation between overall survival and gender (p=0.184), comorbid disease (p = 0.30), clinical presentation (p = 0.884), or tumour lateralization (p = 0.159). Multivariate analysis showed that overall survival was significantly correlated with SIR based on NLR (HR: 2.41), and ECOG performance status (HR: 1.53). The prognostic factors that affected survival, other than SIR, were Eastern Cooperative Oncology Group (ECOG) performance status (p = 0.003), and tumour localization (p = 0.006). Conclusion: The present findings confirm that NLR based on peripheral blood counts prior to treatment can be used as a prognostic factor in patients with glioblastoma. Since tumour aggression increases and survival decreases as the NLR value rises, choice of treatment modality is facilitated for glioblastoma patients.

Lung Adenocarcinoma Metastasis Mimicking Peripheral Nerve Sheath Tumor: A Case Report and Review of the Literature

Root metastases of solid organ carcinomas are rare entities. Because of their rare occurrence, they can be confused with nerve sheath tumors, such as schwannomas or neurofibromas, when detected by magnetic resonance imaging. In this paper, we reported a case of a 72-year-old woman with S1 root metastasis originating from lung adenocarcinoma. In addition, we reviewed the literature and presented the diagnosis and treatment stages of this pathology. Surgical resection should be the main treatment for symptomatic metastases. Gross total resection of tumors is usually not possible with preservation of neurologic functions. Nerve root decompression, subtotal resection, and adjuvant treatments seem to represent the best treatment option for these patients.

Effectiveness of Platinum-Based Treatment for Triple Negative Metastatic Breast Cancer: a Meta-Analysis

Background: Triple-negative breast cancer (TNBC) is a sub-group of breast cancers with a particularly poor prognosis. The results of studies investigating the role of platinum-based chemotherapy (PBC) in metastatic TNBC (mTNBC) have been conflicting. In this meta-analysis, our aim was to assess the effectiveness of PBCs for mTNBCs. Methods: The PubMed, Cochrane Controlled Trials Register Databases, and EBSCOhost databases were accessed. The English language was used as the search language and only human studies were included. The Newcastle–Ottawa Quality Assessment Scale and the Jadad scoring system were used to evaluate the quality of the included randomized controlled studies. Results: Seven studies and 1,571 patients were included in this meta-analysis. The pooled hazard ratio (HR) for overall survival (OS), evaluated on the basis of six studies, showed the use of PBC regimes to be related to OS in mTNBCs (HR 0.620; 95% CI 0.513-0.749; p:<0.001). Four studies containing HR and abstract statistics used for HR calculation were included in the meta-analysis for progression-free survival (PFS). The pooled HR again indicated a significant relation (HR, 0.628; 95% CI, 0.501-0.786; p:<0.001). Conclusions: In this meta-analysis, we confirmed that PBC regimes provide OS and PFS advantages compared to non-PBC regimes. The use of PBC regimes could be a good choice in mTNBC patients for better quality of life and survival.

Gender Classification Based on Binary Haar Cascade

The present invention relates to a gender classification method based on a binary haar cascade. More particularly, the gender classification method based on a binary haar cascade detects a pedestrian region from a screen image after learning the features of women such as female images, makeup, hair styles, ear rings, or glasses types, determines whether there are the features of women from the pedestrian region, and distinguishes the sex of pedestrians by displaying detection for the heads of the pedestrians in the pedestrian region of the screen image when the features of the women exist.