User Experience Evaluation in BCI: Filling the Gap

Brain-computer interface (BCI) systems can improve the user experience (UX) when used in entertainment technologies. Improved UX can enhance user acceptance, improve quality of life and also increase the system performance of a BCI system. Therefore, the evaluation of UX is essential in BCI research. However, BCI systems are generally evaluated according to the system aspect only so there is no methodology to evaluate UX in BCI systems. This paper gives an overview of such methods from the human-computer interaction field and discusses their possible uses in BCI research

How much control is enough? Optimizing fun with unreliable input

Brain-computer interfaces (BCI) provide a valuable new input modality within human- computer interaction systems, but like other body-based inputs, the system recognition of input commands is far from perfect. This raises important questions, such as: What level of control should such an interface be able to provide? What is the relationship between actual and perceived control? And in the case of applications for entertainment in which fun is an important part of user experience, should we even aim for perfect control, or is the optimum elsewhere? In this experiment the user plays a simple game in which a hamster has to be guided to the exit of a maze, in which the amount of control the user has over the hamster is varied. The variation of control through confusion matrices makes it possible to simulate the experience of using a BCI, while using the traditional keyboard for input. After each session the user �lled out a short questionnaire on fun and perceived control. Analysis of the data showed that the perceived control of the user could largely be explained by the amount of control in the respective session. As expected, user frustration decreases with increasing control. Moreover, the results indicate that the relation between fun and control is not linear. Although in the beginning fun does increase with improved control, the level of fun drops again just before perfect control is reached. This poses new insights for developers of games wanting to incorporate some form of BCI in their game: for creating a fun game, unreliable input can be used to create a challenge for the user

Human-Computer Interaction for BCI Games: Usability and User Experience

Brain-computer interfaces (BCI) come with a lot of issues, such as delays, bad recognition, long training times, and cumbersome hardware. Gamers are a large potential target group for this new interaction modality, but why would healthy subjects want to use it? BCI provides a combination of information and features that no other input modality can offer. But for general acceptance of this technology, usability and user experience will need to be taken into account when designing such systems. This paper discusses the consequences of applying knowledge from Human-Computer Interaction (HCI) to the design of BCI for games. The integration of HCI with BCI is illustrated by research examples and showcases, intended to take this promising technology out of the lab. Future research needs to move beyond feasibility tests, to prove that BCI is also applicable in realistic, real-world settings

Tumores adenomatoides uterinos: estudio anatomo-patológico e inmunohistoquímico de 32 casos

Indexación: ScieloAntecedentes: Los tumores adenomatoides (TA) son poco frecuentes. Se encuentran principalmente en el aparato reproductor femenino y especialmente en el útero. No existen reportes a nivel nacional sobre estos. Objetivos: Describir las características histológicas e inmunohistoquímicas de los TA uterinos. Método: Estudio descriptivo de 32 muestras ingresadas al Servicio de Anatomía Patológica de Clínica Las Condes. Las muestras estudiadas fueron recopiladas entre noviembre de 1999 y noviembre de 2008. Resultados: El diagnóstico de TA fue realizado en 21 histerectomías y 11 miomectomías. En 14 casos se diagnosticaron como lesiones nodulares únicas (43,8%) y en 18 junto a leiomiomas (56,2%). El tamaño promedio de las lesiones únicas fue 2,6 cm, significativamente mayor que aquellas asociadas a leiomiomas. El patrón histológico predominante más frecuente correspondió al tipo angiomatoide (81,3%), seguido por los patrones adenoide (9,4%), sólido (6,3%) y mixto (3%), no se encontraron TA quísticos. El estudio inmunohistoquími-co fue positivo en el 100% de los casos para citoqueratina AE1/AE3, calrretinina, vimentina y D2-40. Fue negativo para CD31 y CEA. Sólo un 6,3% (2 casos) fue positivo para citoqueratina 5/6. Conclusiones: Los TA corresponden a tumores benignos de origen mesotelial. Generalmente su diagnóstico es un hallazgo. Al presentarse en el útero, se confunden generalmente con leiomiomas o se presentan en conjunto con estos. En base a lo anterior el tratamiento de estas lesiones debe ser conservador, bastando con la resección del tumor.Background: The adenomatoid tumors (AT) are rare. They are found mainly in the female reproductive system and especially in the uterus. There is not national reporting on these. Objective: To describe the his-tological and immunohistochemical features of uterine AT. Method: Descriptive study of 32 patients admitíed to the Pathology Department of Clinica Las Condes. The cases studied were collected between November 1999 and November 2008. Results: The diagnosis of AT was performed in 21 hysterectomies and 11 myomectomies. In 14 patients were diagnosed as nodular single lesions (43.8%) and in 18 cases associated with leiomyomas (56.2%), the average size of single lesions was 2.6 cm, significantly greaterthan those associated with leiomyomas. The predominant histologic type most often correspond to angiomatoid (81.3%), followed by adenoid patterns (9.4%), solid (6.3%) and mixed (3%), the cystic pattern was not observed. The immunohistochemical study of ST was positive in 100% for cytokeratin AE1/AE3, calrretinin, vimentin and D2-40. It was negative for CD31 and CEA. Only 6.3% (2 cases) were positive for cytokeratin 5/6. Conclusio-ns: The AT is a benign tumor of mesothelial origin. Usually the diagnosis is a finding. In the uterus they are generally mistaken with leiomyomas or it is in associated with them. Based on the foregoing the treatment of AT should be conservative, only with resection.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-75262009000600009&nrm=is

On the Solutions of the Lorentz-Dirac Equation

We discuss the unstable character of the solutions of the Lorentz-Dirac equation and stress the need of methods like order reduction to derive a physically acceptable equation of motion. The discussion is illustrated with the paradigmatic example of the non-relativistic harmonic oscillator with radiation reaction. We also illustrate removal of the noncasual pre-acceleration with the introduction of a small correction in the Lorentz-Dirac equation.Comment: 4 eps figs. to be published in GR

Bacteria Hunt: A multimodal, multiparadigm BCI game

Brain-Computer Interfaces (BCIs) allow users to control applications by brain activity. Among their possible applications for non-disabled people, games are promising candidates. BCIs can enrich game play by the mental and affective state information they contain. During the eNTERFACE’09 workshop we developed the Bacteria Hunt game which can be played by keyboard and BCI, using SSVEP and relative alpha power. We conducted experiments in order to investigate what difference positive vs. negative neurofeedback would have on subjects’ relaxation states and how well the different BCI paradigms can be used together. We observed no significant difference in mean alpha band power, thus relaxation, and in user experience between the games applying positive and negative feedback. We also found that alpha power before SSVEP stimulation was significantly higher than alpha power during SSVEP stimulation indicating that there is some interference between the two BCI paradigms