Zernike Moment Based Classification of Cosmic Ray Candidate Hits from CMOS Sensors.

Reliable tools for artefact rejection and signal classification are a must for cosmic ray detection experiments based on CMOS technology. In this paper, we analyse the fitness of several feature-based statistical classifiers for the classification of particle candidate hits in four categories: spots, tracks, worms and artefacts. We use Zernike moments of the image function as feature carriers and propose a preprocessing and denoising scheme to make the feature extraction more efficient. As opposed to convolution neural network classifiers, the feature-based classifiers allow for establishing a connection between features and geometrical properties of candidate hits. Apart from basic classifiers we also consider their ensemble extensions and find these extensions generally better performing than basic versions, with an average recognition accuracy of 88%.

CNN-Based Classifier as an Offline Trigger for the CREDO Experiment.

Gamification is known to enhance users' participation in education and research projects that follow the citizen science paradigm. The Cosmic Ray Extremely Distributed Observatory (CREDO) experiment is designed for the large-scale study of various radiation forms that continuously reach the Earth from space, collectively known as cosmic rays. The CREDO Detector app relies on a network of involved users and is now working worldwide across phones and other CMOS sensor-equipped devices. To broaden the user base and activate current users, CREDO extensively uses the gamification solutions like the periodical Particle Hunters Competition. However, the adverse effect of gamification is that the number of artefacts, i.e., signals unrelated to cosmic ray detection or openly related to cheating, substantially increases. To tag the artefacts appearing in the CREDO database we propose the method based on machine learning. The approach involves training the Convolutional Neural Network (CNN) to recognise the morphological difference between signals and artefacts. As a result we obtain the CNN-based trigger which is able to mimic the signal vs. artefact assignments of human annotators as closely as possible. To enhance the method, the input image signal is adaptively thresholded and then transformed using Daubechies wavelets. In this exploratory study, we use wavelet transforms to amplify distinctive image features. As a result, we obtain a very good recognition ratio of almost 99% for both signal and artefacts. The proposed solution allows eliminating the manual supervision of the competition process.

Prediction of PTSD in police officers after six months--a prospective study.

The aim of this prospective study was to explore the predictors for the development of PTSD in police officers six months after encountering situations of a potentially traumatic nature. Fifty-nine police officers were studied immediately after the event (T1) and six months later (T2). At T2 PTSD was assessed using the Structured Clinical Interview for DSM-IV (SCID-I). PTSD was predicted by intrusions (Impact of Event Scale-Revised; IES-R), the impairment scale (is), global assessment of functioning scale (GAF), gender, age and sense of coherence scale (SOC). The diagnosis of an acute stress disorder (ASD) at T1 had a high specificity for identifying PTSD at T2. The strongest predictor for the development of PTSD was found to be the factor intrusions. Contrary to our expectations, age was not a significant predictive factor for PTSD. Thus, acute stress disorder (ASD) and a high degree of intrusions experienced immediately after a traumatic incident helped to identify early police officers at risk of developing chronic PTSD.

[Coping mechanisms of police officers with mental and psychosomatic symptoms after an event of potential psychotraumatic nature]. / psychotraumatischen Ereignis.

OBJECTIVES: This prospective study analyzes the coping mechanisms of police officers directly after an event of potential traumatic nature in the line of duty (e. g. use of firearms) as well as 6 months later. METHOD: 59 police officers were contacted by professional crisis intervention teams of the police force. After an extended interview, an ICD-10 diagnosis, if applicable, was assigned. Six months later a diagnosis was derived by a clinician (Diplom-Psychologe) using a structured interview. Coping strategies were accessed by the FKV (Freiburger Fragebogen zur Krankheitsverarbeitung) questionnaire. RESULTS: Fourteen police officers (28%) received the diagnosis of a PTSD (ICD-10: F43.1) at 6 months. The coping mechanisms of the traumatized police officers were significantly elevated in a dysfunctional manner in the areas "emotional control and social retreat" (only directly after the event), "regression", "mistrust and pessimism", and "depressive processing". CONCLUSIONS: Because dysfunctional coping mechanisms impede the decline of the symptoms, it may be considered adequate to strengthen the coping mechanisms for functional coping with these symptoms, thereby focusing on the dysfunctional coping strategy specific to the police force, namely, emotional control.

[Quality of psychological strain in police work--development of a taxonomy of sources of stress]. / Klassifikation psychischer Belastungen innerhalb der Polizei - Entwicklung einer Taxonomie der Belastungsqualitäten.

OBJECTIVES: Police officers frequently face traumatic stressors of different origins and thus bear an increased risk of developing a post-traumatic stress disorder. The most mentally burdening situations range from shootings, death of fellow officers, dealing with dead bodies in general, the effects of shift work, time pressure or discontent with management due to mobbing. Part of the present study examines the quality of stress in police work with the goal of developing a taxonomy of the origins of stress. METHODS: A stratified sample of 109 police officers participated in the study. They were interviewed about stressful situations in their work life. In the interviews participants generated incidents describing stressful or straining situations. These incidents were used to develop a taxonomy of stressful situations in everyday police work. A further 22 interviews with officers of the federal police were carried out to examine the transferability of the developed taxonomy to other occupational groups. RESULTS: The taxonomy distinguishes between five sources of strain. Strain can arise from (1.) the task itself, (2.) the organization and structure of work, (3.) the temporal conditions and (4.) the social conditions. The fifth category describes the source of strain based on other conditions. The results also show that the taxonomy is transferable to other occupational groups. CONCLUSIONS: This taxonomy leads to the systematisation of the differences among the stress phenomena which occur in police work. The results can help in the development of practical prevention, counselling and therapeutic programs.

[Psychodynamic therapy foci in inpatient psychotherapy--relations to self-assessment scales and individual therapeutic goals]. / Psychodynamische Therapiefoki in einer stationären multimodalen Therapie--Zusammenhänge zu den Selbstauskunftskalen und Individuellen Therapiezielen.

OBJECTIVES: How do the OPD-based psychotherapy foci formulated by the therapeutic team at the patient's admission develop and how do they relate to change in symptoms and to the patient's individual therapeutic goals? METHOD: After Operationalized Psychodynamic Diagnostics (OPD) in 188 psychotherapy inpatients, 2-3 clinically relevant OPD foci were chosen in joint team sessions after admission and assessed by the Heidelberg Structural Change Scale (HSCS) at the beginning and the end of inpatient psychotherapy. Patients formulated their individual therapy goals at the beginning and assessed their achievement at the end of inpatient psychotherapy and filled in self-assessment scales. RESULTS: At the end of therapy there was a significant mean improvement of one step on the Heidelberg Restructuring Scale for all three foci (0.9-1.2) in the sample as a whole. In approximately one-fourth of the patients we observed no change in the HSCS (25.5-27.7 %), approximately 70 % improved one to four steps towards higher awareness of, coping with or restructuring of the focus. The hypothesis of high correlations between the different measures of change could be supported only in part. DISCUSSION: The clinical implications and the implications for quality management are discussed.

[Secondary prevention for police officers involved in job-related psychologically stressful or traumatic situations]. / Sekundärprävention bei schwerer Belastung und Traumatisierung durch beruflich bedingte Exposition im Polizeidienst.

OBJECTIVES: Police officers are at high risk of being exposed to psychologically straining situations and potentially psychotraumatic experiences. In this article, such situations are exemplified and categorized, and the role and significance of secondary prevention following traumatic experiences is discussed. METHODS: From 1994 to 2003, 649 police officers received secondary prevention after being involved in a total of 250 potentially traumatic or psychologically stressful incidents. Psychological support was provided by teams of specially trained professionals in the acute phase after the incident following careful psychological evaluation. In a retrospective evaluation, the diagnoses obtained were analyzed with regard to sex and age and correlated with the severity of the incident. Three clusters of potentially traumatic situations were formed: (1) Employment of fire-arms with danger for the officer, (2) Standard situations including violence towards a third party, (3) Suicide or attempted suicide of a police officer. RESULTS: Police officers who experienced events assigned to cluster (1), comprising situations with considerable traumatic potential, had the highest incidence of posttraumatic stress disorder (PTSD) or other mental illness. Compared to male officers, females were more often diagnosed with other mental illness, whereas males had a higher incidence of PTSD. Cluster (2), which comprised situations of an officer's daily professional life, was not associated with an increased risk of mental illness. Officers were apparently capable of coping with situations considered psychologically straining for the general public without detectable evidence of a traumatic reaction. In cluster (3), which reflects the most dramatic interference with team relations, other forms of mental illness were diagnosed at a higher incidence.