DIALECT—Network-based digital interactive lectures Apostolopoulos, Nicolas; Geukes, Albert; Zimmermann, Stefan
Computer networks and ISDN systems,
11/1996, Volume:
28, Issue:
14
Journal Article, Conference Proceeding
Peer reviewed
In the information society of today the access to information is a fundamental right and a strong demand for cost effective just-in-time distance learning can be observed. The newest technical ...achievements in the fields of telematics and multimedia offer new ways for the design and distribution of learning material. Different approaches have already been tested successfully. The degree of involvement of a human expert during the learning process with computer based material is still under investigation.
The work presented in this paper deals with the problem of converting university lectures into multimedia based digital learning material (learnware). The courses called Digital Interactive Lectures (DIALECT) require minimal interaction with the teacher and can be distributed over a broadband communication network. In order to increase the acceptance of DIALECT material a new model based on an integrated concept has been developed. It eliminates many of the weaknesses of traditional CBT courses and modern Open Distance Learning. Basically a “realistic story” that illustrates the theory to be presented and the accompanying case study (exercise) is developed and integrated into the lecture. This is accomplished with the help of interactive video which is used to present the topic, to guide through the parts of the lecture and to catch the students' attention.
DIALECT makes use of animation, computer simulation, and hyperlink facilities. The authors' interface is based on the notion of hyperlinked scripts and enables the inclusion of the appropriate media where needed. A corresponding framework for programmers that allows for easy and efficient use of multimedia-based presentation tools has been developed. Special attention has been paid to the user front-end in terms of screen design, interactivity and good video/audio quality.
The lectures are stored in compressed format on a UNIX server and can be presented on low-cost multimedia Windows PCs. Real time distribution over a digital network requires Quality of Service features because of the demand for constant bit transfer rate for the videos. DIALECT applications are well suited for ATM networks or high speed LANs.
First evaluation results show a high degree of acceptance. Will high quality multimedia lectures in some years compete with inferior-performing teachers?
Identifying and comparing different steady states is an important task for clinical decision making. Data from unequal sources, comprising diverse patient status information, have to be interpreted. ...In order to compare results an expressive representation is the key. In this contribution we suggest a criterion to calculate a context-sensitive value based on variance analysis and discuss its advantages and limitations referring to a clinical data example obtained during anesthesia. Different drug plasma target levels of the anesthetic propofol were preset to reach and maintain clinically desirable steady state conditions with target controlled infusion (TCI). At the same time systolic blood pressure was monitored, depth of anesthesia was recorded using the bispectral index (BIS) and propofol plasma concentrations were determined in venous blood samples. The presented analysis of variance (ANOVA) is used to quantify how accurately steady states can be monitored and compared using the three methods of measurement.
The anesthetic agent propofol is applied intravenously and different groups demonstrated that it is detectable in breathing gas. To quantify the propofol concentration in breathing gas (c breath ) ...might be a promising feedback for anesthesiologist and for potential closed loop control, yet there is no online measurement in standard clinical practice. Since the physiological relevance of the propofol concentration in breath is not entirely known it may be adverse to control the infusion with c breath as target variable. In order to control the concentration at the plasma site (c plasma ) or even at the effect site (c effect ) in the brain mathematical models can be used to describe the dependencies between c breath and c plasma or c effect . This contribution presents the pharmacokinetic modeling of the transition from blood to alveolar gas concentration of propofol. For characterization a model described by a gas blood partition coefficient and one time constant or an equivalent one compartment system, respectively, is taken into account. Clinical data obtained in a study with 17 patients are used for fitting. During anesthesia breathing gas was monitored continuously with an electrochemical sensor and venous blood samples were taken at given times. The use of the mentioned model structure leads to a simple and adequate characterization. A data conditioning in form of a model based interpolation was performed prior to the identification process. The identified parameters are comparable to results of other research works.
The effect of methane gas seepage on the small scale distribution of oxygen and sulphide within muddy seep sediments was studied at a site 310–340 m deep in the Central Skagerrak. The concentrations ...of oxygen and sulphide were measured in ☐cores (0.5 × 0.5 m) using needle-electrodes, at 2 cm intervals horizontally along a transect across small seeps, and vertically at 1–10 mm intervals to a depth of 10 cm. The seep sediments, which were densely colonised by the pogonophoran
Siboglinum poseidoni and the bivalve mollusc
Thyasira sarsi, had high methane concentrations of up to 2567.8 μmol dm
−3 sed. in the upper 13 cm of the sediment.
In sediments within 10 cm of the seep outlet relatively high concentrations of oxygen, up to 48 μmol O
2 1
−1 porewater at 10 cm depth, were found, while in adjacent non-seep sediments similar concentrations of oxygen were found only in the top 1 cm. This distribution of oxygen indicates that deep penetration of overlaying sea water into the sediment occurs, probably induced by the ebulition of methane gas, as has been described from sandy sediments. Elevated dissolved sulphide concentrations were detected around the periphery of the oxygen penetration zones, and may be attributed to locally increased sulphate reduction fuelled by the sulphate and organic substrates drawn down into the sediment.
Hematopoietic stem cells (HSCs) provide the basis for the enormous regenerative capacity of the hematopoietic system. Despite the need for a lifelong production of blood cells, replicative exhaustion ...seems to affect the HSC pool. Erosion of telomeres, protective structures at the ends of eukaryotic chromosomes, limits the replicative life span of most somatic cells. The expression of telomerase, the enzyme synthesizing telomeres de novo, is restricted to highly proliferative cells like germ line cells and tumor cells. Adult stem cells such as HSCs still exhibit telomerase activity to a certain level. Here, the telomerase activity does not prevent telomere shortening, suggesting a restriction of the proliferative capacity of HSCs. In this review, we discuss the relevance of telomere maintenance, potential functions of telomerase, and possible clinical applications of telomere manipulation in the hematopoietic stem cell compartment. Furthermore, we discuss new insights affecting the aging of the hematopoietic stem cell pool besides replicative exhaustion.
There once was a time when the actual attraction of a movie lied in the capability of the celluloid to let the spectators escape from the everyday, a spare time to leave the life-world environment ...behind and live the life of a thrilling armchair traveller. Foreign countries and remote regions could easily be mapped and visited without travelling to the actual location. Considering that “the modern world is very much a ‘seen’ phenomenon“ (Jenks 1995:2), one has to come to the assumption that present day travelling and watching movies are somehow connected. Tourism originally was perceived as visitors travelling, whether within their own country or internationally, for pleasure and relaxation. However, over the years, tourism has evolved into different components and labels.
We empirically explore the relevance of risk taking behavior in tournaments. We make use of data from the NBA season 2007/2008 and measure risk taking by the fraction of three-point shots. Current ...heterogeneity of teams is taken into account by intermediate results. It turns out that indeed teams who are behind increase the risk in terms of more three-point attempts. We additionally analyze the consequences of this change in behavior. Enhanced risk taking is inefficient for the vast majority of cases and only beneficial in terms of a higher winning probability if a team is behind with a rather large amount of points. We discuss possible explanations for these decision errors.
PDF
