Religion: An Ambiguous and Questionable Concept

International Symposium: The fossil man of Monte Circeo: Fifty years of studies on the Neandertals in Latium (19–21 October, 1989)

Ambiguity in English and Albanian Sentences

Objectives This paper considers the particular challenges of classification in relation to retired or outdated terms. While reasons for the revision or elimination of terms are varied, the consequences and possible solutions may have much in common. Building on an earlier paper on types of ambiguity in classification (Rajan 2017), the author extends an inquiry into this type of classificatory challenge by looking at examples from the recent and more distant past. While solutions to these challenges emerge from the context of the classification system and the needs of the disciplines which they serve, it may be useful to outline the features of historical ambiguity to inform future conversations and allow cross-disciplinary conversations about how we approach these challenges. Tracing the contours of historical ambiguity may also suggest approaches for multiple stakeholders to engage with term changes when needs emerge. MethodsThis paper extends a vocabulary developed in the course of my research into the nature or contents of otherness. While the literature of classification offers abundant evidence and nuanced discussion of the consequences of othering, there is limited discussion of non-human entities that are othered. In this paper, I apply my earlier taxonomy of ambiguity to particular cases of terms that have fallen out of favor. Extending on Tennis’s work on eugenics in the DDC (2012), I will trace the way in which the “science” of eugenics became ambiguous over time as understanding of the practice and consequences of the discipline changed. While eugenics had profound effects on individuals, the term is not tied to human identity groups. In contrast, the term Asperger’s, used until recently in the DSM as a diagnosis within the autism spectrum, was taken up by many as a term of identity. I will illustrate the strange ambiguity of a term that is officially unrecognized but popularly used, including responses to these changes proposed by members of the affected communities (Zolyomi and Tennis 2017). Finally, I will consider the ambiguity of classification of Asian Americans in the DDC and question how revisions to these terms resolve or fail to resolve this ambiguity (Higgins 2016). In my earlier paper, I suggested that historical ambiguity was a form of what I called conditional ambiguity, all forms of which require some sort of narrative resolution to accurately represent their complex and contextual identities. Revisiting historic terms, I will explore whether there are non-narrative solutions. I will also consider the relationship between historical ambiguity and what I previously termed privacy-related ambiguity, when identities are intentionally obscured or made inaccessible to those who seek to classify them. Areas of overlap may be substantial, for instance, in the realm of indigenous knowledge (Glass 2015). Results Ambiguity is experienced more often than it is described: a confusion antithetical to the aims of classification and other forms of categorization, which are employed to help us make sense of the world. In recent decades, a wide range of scholarship has exposed the consequences of classification. From Bowker and Star’s investigation of classification systems across disciplines (1999, 2007) and Olson’s examination of subject terms in library classifications (2002) to more recent work on representation of race (Furner 2007, Higgins 2016), gender (Adler 2009, Fox 2016b) and neurodiversity (Zolyomi and Tennis 2017), the consequences of othering have been amply illustrated. While the framing of othering has been critical in describing the consequences of classification, the concept did little to illuminate how things became other. concept of ambiguity was proposed as a way to see whether others have any commonality beyond the fact of their misrepresentation (Rajan 2017). Four types of ambiguity were outlined: multiplicity describes cases where the identity of an entity is more extensive or intersectional than the classification system allows; emergence occurs when phenomena are newly observed and identity has not concretized; privacy-related ambiguity is when those classifying are distrusted by the communities subject to representation. Conditional ambiguity describes entities or phenomena that require contextual description for accurate representation, including historical ambiguity, referring to situations where terminology has changed. cases of eugenics and Asian American representation, both in the DDC, and the elimination of the term ‘Aspergers’ from the DSM-V are all illustrative of the concept of historical ambiguity. Terms related to Asian Americans and neurodiversity are both related to human identity groups, while eugenics stands apart as a description of a practice once considered scientific. While the consequences of the othering in each of case is unique to the affected community, from the perspective of those engaged in classification, the examples of eugenics and Aspergers pose the same challenge: how to describe something that was once seen as legitimate and is now considered illegitimate or inaccurate? Must a new accurate representation include some historical context describing the changes in terminology? How would such a description aid the user? In the case of representation of Asian American identity, terminology expanded, yet the question remains how this term relates to historical resources. When and where to apply the term, and to what extent are those classifying responsible for bridging the gap between historical and current terms? Conclusions concept of ambiguity offers a useful lens with which to look at process of classification across systems. In particular, it highlights the qualities that lead to confusion on the part of those who classify and those who look to classification systems for guidance in understanding the world or a domain. Ambiguous resources or entities challenge the efficiency constraints of a system by requiring something closer to a natural-language description to accurately represent. While the concept of historical ambiguity does not offer any specific solutions, it may allow those engaged in the work of classification design and use to anticipate some of the challenges attendant to term change. It may facilitate methods of representation that are both more accurate and accessible to those who seek information about the past and are working to understand the present and future. ReferencesAdler, Melissa. 2009. “Transcending Library Catalogs: A Comparative Study of Controlled Terms in Library of Congress Subject Headings and User-Generated Tags in LibraryThing for Transgender Books.” Journal of Web Librarianship 3: 309–331. https://doi.org/10.1080/19322900903341099. Beghtol, Clare. 1986. “Semantic validity: concepts of warrant in bibliographic classification systems.” Library Resources and Technical Services 30: 109-125.Bowker, Geoffrey, and Susan Leigh Star. 1999. Sorting Things Out: Classification and Its Consequences. Cambridge, Ma: MIT Press. Feinberg, Melanie, Daniel Carter, and Julia Bullard. 2014. “A story without end: writing the residual into descriptive infrastructure.” DIS 2014 - Proceedings of the 2014 ACM SIGCHI Conference on Designing Interactive Systems, Vancouver, Canada, June 21-15, 2014. 385–394. https://doi.org/10.1145/2598510.2598553 Fox, Melodie. 2016a. “Priorities of arrangement or a hierarchy of oppressions?: Perspectives on intersectionality in knowledge organization.” Knowledge Organization, 43: 373-383. Fox, Melodie. 2016b. “Subjects in Doubt: Ontogeny of Intersex in the Dewey Decimal Classification.” Knowledge Organization 43: 581-593. Furner, Jonathan. 2007. “Dewey deracialized: A critical race-theoretic perspective.” Knowledge Organization, 34(3), 144-168. Furner, Jonathan. 2009. “Interrogating ‘Identity’: A Philosophical Approach to an Enduring Issue in Knowledge Organization.” Knowledge Organization 36: 3–16. Giles, David C. 2014. “‘DSM-V Is Taking Away Our Identity’: Reaction of the Online Community to the Proposed Changes in the Diagnosis of Asperger’s Disorder.” Health: 18 (2): 179–195 Glass, Aaron. 2015. “Indigenous Ontologies, Digital Futures: Plural Provenances and the Kwakwaka’wakw collection in Berlin and Beyond.” In Museum as Process: Translating Local and Global Knowledges, ed. Raymond Silverman, 19-44. London: Routledge. Higgins, Molly. 2016. “Totally Invisible: Asian American Representation in the Dewey Decimal Classification, 1876-1996.” Knowledge Organization 43: 609-621. Jacob, Elin K. 2004. “Classification and Categorization: A Difference that Makes a Difference.” Library Trends 52: 515-540. Nissenbaum, Helen. 2004. “Privacy as contextual integrity.” Washington Law Review 79: 119–157. Olson, Hope A. 2002. Power to Name : Locating the Limits of Subject Representation in Libraries. Boston, Ma.: Kluwer Academic Publishers. Rajan, Lilium. 2017. “Ambiguity in Knowledge Organization: Four Proposed Types.” NASKO 6: 239-247. Star, Susan Leigh, and Geoffrey Bowker. 2007. “Enacting silence: Residual categories as a challenge for ethics, information systems, and communication.” Ethics and Information Technology 9: 273–280. https://doi.org/10.1007/s10676-007-9141-7 Tennis, Joseph T. 2012. The Strange Case of Eugenics: A Subject's Ontogeny in a Long‐lived Classification Scheme and the Question of Collocative Integrity. Journal of the American Society for Information Science and Technology 63: 1350-359. Zolyomi, Annuska and Joseph T. Tennis. 2017. “Autism Prism: A domain Analysis Paper Examining Neurodiversity.” NASKO 6: 139-172.

With the widespread dissemination of user-generated content on different social networks, and online consumer systems such as Amazon, the quantity of opinionated information available on the Internet has been increased. One of the main tasks of the sentiment analysis is to detect polarity within a text. The existing polarity detection methods mainly focus on keywords and their naive frequency counts; however, they less regard the meanings and implicit dimensions of the natural concepts. Although background knowledge plays a critical role in determining the polarity of concepts, it has been disregarded in polarity detection methods. This study presents a context-based model to solve ambiguous polarity concepts using commonsense knowledge. First, a model is presented to generate a source of ambiguous sentiment concepts based on SenticNet by computing the probability distribution. Then the model uses a bag-of-concepts approach to remove ambiguities and semantic augmentation with the ConceptNet handling to overcome lost knowledge. ConceptNet is a large-scale semantic network with a large number of commonsense concepts. In this paper, the point mutual information (PMI) measure is used to select the contextual concepts having strong relationships with ambiguous concepts. The polarity of the ambiguous concepts is precisely detected using positive/negative contextual concepts and the relationship of the concepts in the semantic knowledge base. The text representation scheme is semantically enriched using Numberbatch, which is a word embedding model based on the concepts from the ConceptNet semantic network. The proposed model is evaluated by applying a corpus of product reviews, called Semeval. The experimental results revealed an accuracy rate of 82.07%, representing the effectiveness of the proposed model.

Multi-platform Integrated Positioning and Attitude Determination using GNSS

Background: In most circumstances we easily distinguish changes to the external world brought about by our own actions from those with external origins. However, there are contexts where the sense of agency is put into question. Little is known about ambiguity characterised by a lack of information for self-other differentiation, despite its relevance to symptoms and levels of consciousness associated with certain mental health conditions. In this PhD thesis by publication, behavioural and neuroimaging methods are used to explore self-other processing capacities in ambiguous conditions. Individual differences are examined in relation to brain response with the aim of shedding light and generating further testable hypotheses on mechanisms of agency in both health and psychosis. Chapter 2: Building on ideas from developmental and perceptual psychology, Chapter 2 lays out the theoretical framework and rationale behind the experimental work. The paper defines the concept of ambiguity in relation to self-other processing. With caregiver-infant interactions and social interactions more generally described as inherently ambiguous, a key proposal is that experience in ambiguity-promoting settings provide conditions necessary for developing reality-testing abilities and a flexible sense of self-other associated with mental heath. Such abilities may be malleable, however, continuing to develop through experience in activities involving intricate joint action such as social dialogue. It is argued that activities such as music-making which require self-other distinctions, yet make differentiation challenging may particularly hone these skills. Implications for phenomena such as hallucinations associated with reduced attributional abilities are discussed. Chapter 3: In the first experimental study, a task was developed that manipulates ambiguity by controlling the probability that a participant’s finger taps results in auditory tones as opposed to tones generated by ‘another’s finger taps’. The ability to accurately attribute actions to self and to other was negatively related to hallucination proneness (HP) and positively related to musical experience (ME). This pattern of results was accentuated by ambiguous conditions where the probability of self- and other-generated tones was equal. This not only associates HP with specific difficulties in dealing with ambiguity, but also supports the notion that attribution abilities are malleable and can improve through experience in ambiguous settings such as those involving intricate joint action. Chapter 4: Chapter 4 investigated neural responses to modulating the degree of control belonging to self and other using the probability method tested in Chapter 3 in a parametric fMRI block design. Linear and non-linear stimulus-response functions highlighted a network of brain regions previously associated with motor control and self-other processing to be particularly sensitive to control belonging to self. All regions also displayed significant non-linearity with decreased response in ambiguous conditions. This study provides initial insight into attributional ambiguity-processing in the brain. Chapter 5: In Chapter 5, neural responses to the task were examined in relation to individual differences. Combining whole-brain univariate and a task-based ICA approach, results showed increased ambiguity-related response in sensory and DMN regions to be related to positive schizotypy and difficulties in processing ambiguity, in contrast to task performance and musical experience which correlated with reduced response. Chapter 6: The final study examined the effects of attribution performance, including performance specifically related to ambiguity, on resting-state functional connectivity using ICA, dual regression and a network analysis. Findings showed connectivity between frontal networks and other brain regions increased with reduced task performance. Conclusions: The thesis concludes with a discussion of these collective findings and implications for future research. Together the behavioural and imaging findings point towards the importance of ambiguity in self-other processing. Increased insight into the topic may enhance our understanding of agency mechanisms underlying ‘self-disorders’ such as schizophrenia and eventually contribute to extending the range of therapeutic possibilities.

While defining language, its being a means of communication is always highlighted. Languages have evolved to allow individuals to express themselves and exchange information. Having said that, it is questioned why languages, as a primary tool for communication, are full of ambiguities occurring at almost all linguistic levels. To answer this question, this paper attempts to analyze the concept of linguistic ambiguity examining its role and function in the language. For achieving this purpose, the concept of ambiguity has been explained thoroughly and argued that despite some occasional misunderstandings in communication, ambiguity is a merit of a language rather than a drawback for humans who have inherent and sophisticated cognitive mechanisms to understand what is meant. The claim that ambiguity is a curse not a blessing is applicable to computer sciences where Natural Language Processing is inhibited due to ambiguity. Arising from the disproportion between linguistic items and realities, ambiguity should be regarded as a natural evolutionary outcome thanks to which easier and shorter words are reused making the language more efficient.

This article compares Walter Benjamin’s concept of demonic ambiguity in his essay “Toward A Critique of Violence” to the polemical analyses and legal-philosophical arguments presented by the young Karl Marx in a series of journal articles about legal reforms concerning the customary rights of poor people to gather fallen wood. Arguing that in Benjamin, demonic ambiguity arises from the suppression of the inherent, irreducible ambiguity of any legal matter, the article retraces how Marx’s critique uncovers a similar suppression at the origin of modern law, specifically regarding certain customary rights based on the ambiguous nature of their objects, such as fallen wood. The essay concludes with a discussion of Benjamin’s concept of ambiguity, “prägnant” in the German original.

Paradoxes are useful in science because they hint at errors or inconsistencies in our models of the world. In this thesis, I study two well-known and long-standing paradoxes in decision theory from the point of view of neuroeconomics. This approach combines tools and ideas from economics and neuroscience, and tries to understand the neural mechanisms and the causal structures behind these paradoxes. Since its introduction in Ellsberg (1961), the Ellsberg Paradox has been one of the most studied violations of subjective expected utility theory (SEU). In one version of the paradox, a decision-maker is confronted containing two urns with 100 balls that are either red or blue. In the first (risky) urn, she is told there are 50 red and 50 blue; whereas no further information is given about the second (ambiguous) urn. A commonly observed choice pattern is for decision makers to choose to bet on both red and blue in the first urn. Clearly, if probabilities are additive, such rankings are inconsistent with SEU. First, I present brain imaging that shows that the brain treats risky and ambiguous choices differently. This is done through the use of functional magnetic resonance imaging (fMRI), a method that measures brain activity indirectly through blood flow. I find evidence that the brain regions respond differently to ambiguity and risk. Furthermore, the region that is correlated with expected money value of choices are activated more under risk than ambiguity, confirming that expected utility of ambiguous gambles are lower than those of equivalent risk gambles. Finally, the temporal relationship between the regions suggests a network where one brain region signals the level of uncertainty (amygdala), sent through another region (orbitofrontal cortex), and increases (decreases) expected utility of the choices, represented in the activity of a third region (striatum). Brain imaging results, however, is limited by its correlational nature. To assess necessity, if a particular brain region causes a certain behavior, taking it out should remove that behavior. Conversely, to assess sufficiency, stimulating the brain region should create that behavior. In the former, I study patients who have damage to the orbitofrontal cortex (same region found in the brain scans). I find that these patients were both ambiguity- and risk-neutral. This compares to ambiguity- and risk-averse behavior of patients with damage to other parts of the brain not found in the brain scans, similar to normal individuals. This confirms the idea that specific brain regions are necessary for distinguishing between risk and ambiguity. In the latter, I activate amygdala of (normal) subjects through mild electrical stimulation (a method known to elicit activation of the region). This allows us to test whether this method increases the ambiguity/risk aversion of subjects. The third chapter studies the Allais Paradox and the probability weighting function. The fact that people do not appear to weight probabilities linearly as dictated by subjective expected utility theory has been known since the 1950s. More specifically, people have been found to overweight small probabilities, and underweight large probabilities. This chapter has two goals. First, I attempt to find the neural correlate of the probability weighting function: that is, is the probability weighting function as discussed in the decision theory literature found in the brain? Second, I posit a hypothesis for the generation of the probability weighting function with data from psychophysics and neuroscience. Together they shed light on how the brain encodes probabilities as a physical quantity as well as how it might combine decision weights and rewards to calculate expected utility.

Modern surveillance radars are designed to detect moving targets of interest in an adverse environment, which can encompass strong unwanted reflections from ground or sea surface, clouds, precipitation, etc. Detection of weak and small moving targets in environmental clutter remains, however, a challenging task for the existing radar systems. One of the main directions for modern radar performance improvement is the application of wideband high-resolution waveforms, which provide detailed range information of objects in the observed scene. Together with such inherent advantages of wideband waveforms as multi-path separation, clutter reduction and improved target classification, additional benefits can be obtained by exploiting target range migration (range walk), essential for fast moving targets in the high-resolution mode. This thesis aims at the development of novel signal processing techniques for migrating target detection in wideband radars. It involves both resolving range-velocity ambiguities and improvement in target discrimination from ground clutter by accounting for target range migration. It is demonstrated that wideband radars can resolve range-velocity ambiguity by transmitting a single long pulse burst with low pulse repetition frequency (PRF) and exploring target range walk phenomena during the burst. The ambiguity function of such waveform still has strong residuals at the locations of ambiguities, called ambiguous sidelobes, which have to be considered in the processing of wideband data. The presence of ground clutter in the observation scene has a detrimental effect on the wideband radar performance. The impact of the clutter Doppler spectrum and waveform parameters on target detection at clutter ambiguities has been investigated. The improvement over the conventional waveform is demonstrated for narrow clutter Doppler spectrum; in the presence of clutter with a wide Doppler spectrum, the conventional staggered-PRF waveform is preferable. Performance degradation at ambiguous-to-clutter velocities is validated on the real data sets. Modern high-resolution parametric-free spectrum estimators – IAA (Iterative Adaptive Approach) and SPICE (Semi-Parametric Iterative Covariance-based Estimator) – are proposed for the reconstruction of the observed scene from wideband radar measurements with no velocity ambiguities. These algorithms demonstrate significant improvement in rejection of ambiguous sidelobes over the conventional techniques. For clutter-limited case, the covariance-aware SPICE is introduced with improved capability to discriminate targets from clutter. The advantages of the proposed methods are demonstrated in numerical simulations and real data processing. The ambiguous sidelobes can cause severe problems for detection of multiple targets located at similar ranges. A dedicated detector for a dense target scenario has been introduced. It can detect multiple closely spaced targets and mitigate false detections due to their ambiguous sidelobes, holding false alarm probability at the required level. The improvement over conventional processing is demonstrated. Special attention is then devoted to clutter suppression in the high range resolution mode. In meter or sub-meter range resolution, the observed ground clutter, modeled by a compound-Gaussian process, may have significant fluctuations over the range interval, elapsed by the target. An advanced detector for range-migrating targets in compound-Gaussian clutter is developed. It performs two-dimensional clutter filtering – in Doppler frequency and in the range – and benefits from clutter spatial diversity, obtained for a target passing over different patches of clutter. A significant improvement in the detection of fast moving targets in spiky clutter is achieved in comparison to the existing methods. The attained gain depends on clutter characteristics and target velocity: fast moving targets are easier to detect than slow ones with equal signal-to-clutter ratio. The generalized approach for detection of range-extended migrating targets is provided. The performed research provides some fundamental insight for implementation of new radar architectures with the utilization of wideband waveforms.

A nondeterministic automaton is called unambiguous if it has at most one accepting run on every input. A regular language is called unambiguous if there exists an unambiguous automaton recognizing this language. Currently, the class of unambiguous languages of infinite trees is not well-understood. In particular, there is no known decision procedure verifying if a given regular tree language is unambiguous. In this work we study the self-dual class of bi-unambiguous languages - languages that are unambiguous and their complement is also unambiguous. It turns out that thin trees (trees with only countably many branches) emerge naturally in this context. We propose a procedure P designed to decide if a given tree automaton recognizes a bi-unambiguous language. The procedure is sound for every input. It is also complete for languages recognisable by deterministic automata. We conjecture that P is complete for all inputs but this depends on a new conjecture stating that there is no MSO-definable choice function on thin trees. This would extend a result by Gurevich and Shelah on the undefinability of choice on the binary tree. We provide a couple of equivalent statements to our conjecture, we also give several related results about uniformizability on thin trees. In particular, we provide a new example of a language that is not unambiguous, namely the language of all thin trees. The main tool in our studies are algebras that can be seen as an adaptation of Wilke algebras to the case of infinite trees.

The aim of this paper is to study the presence of manifold ambiguities [1], [2] in linear arrays. We propose a general framework for the analysis and so we obtain a generalisation of results given in recent publications [3], [4] for an}· rank ambiguities. We present a geometrical construction able to determine all the ambiguous directions which can appear for a given linear array. This is a geometrical approach closely connected to [4]. The method allows determination of any rank ambiguities and for each ambiguous direction set the rank of ambiguity is determined. The search is exhaustive. Application of the method requires no assumption for the linear array and is easy to implement. We apply the method to the search of ambiguities for sparse linear arrays, in particular minimum redundant and non redundant arrays [5], [6], [7]. We show how an ambiguous generator set can be associated to each intersensor distance if the intersensor distances (lags) are all multiples of the half wavelength.

Role ambiguity is often thought to be a pervasive aspect of boundary spanning and sales positions in marketing. Surprisingly, few studies have examined how various types or dimensions of role ambiguity impact the salespersons' psychological (e.g., job satisfaction, tension and commitment) and behavioral (e.g., performance and turnover) outcomes. Because proper intervention begins with an accurate assessment, the purpose of this paper is to measure the various types of role ambiguities experienced by industrial salespeople and to examine their relative effects on psychological and behavioral job outcomes. Specifically, we demonstrate how multidimensional role ambiguity can pinpoint specific dimensions of ambiguity that are dysfunctional to the salesperson and organization. The results underscore the managerial and theoretical insights obtained from utilizing a multidimensional view of role ambiguity as part of a broader survey for examining the dysfunctional effects of role ambiguity dimensions in sales or...

The continuous modernisation of existing Global Navigation Satellite Systems (GNSS) and the development of new systems with a multitude of different carrier frequencies and a variety of signal modulations creates a true multi-GNSS and multi-signal environment available today. Still most precise GNSS processing strategies rely on dual-frequency measurements only by applying the Ionosphere-Free (IF) Linear Combination (LC) of GNSS observables and therefore do not benefit from the available multi-signal environment. While in this processing approach the first order effect of the ionospheric delay can be eliminated almost completely, the formation of linear combinations of GNSS observables leads to a noise increase for the resulting observations and a loss of some of the physical characteristics of the original signals, like the integer nature of the carrier phase ambiguity. In order to benefit from the multi-GNSS and multi-signal environment available today, the scientific analyses and precise applications presented in this work are based on the raw observation processing approach, which makes use of the original (raw) observations without forming any linear combinations or differences of GNSS observables. This processing strategy provides the flexibility to make use of all or a selection of available multi-GNSS and multi-signal raw observations, which are jointly processed in a single adjustment as there is no inherent limitation on the number of usable signals. The renunciation of linear combinations and observation differences preserves the physical characteristics of individual signals and implies that multi-signal biases and ionospheric delays need to be properly determined or corrected in the parameter estimation process. The raw observation processing approach is used in this work to jointly process measurements from up to three different GNSS, including eleven signals tracked on up to eight different carrier frequencies in one single adjustment. The bias handling for multi-GNSS and multi-signal applications is analysed with a focus on physically meaningful parameter estimates to demonstrate the benefits of handling clock offset parameters, multi-signal code biases and ionospheric delay estimates in a physically meaningful and consistent way. In this context, receiver-specific multi-GNSS and multisignal biases are analysed and calibrated by the use of a GNSS signal simulator. The disadvantages of eliminating physical characteristics due to the formation of linear combinations of observations or commonly used parameter estimation strategies are demonstrated and discussed. The carrier phase Integer Ambiguity Resolution (IAR) approach developed and implemented in the course of this work is based on the joint processing of multi-GNSS and multi-signal raw observations without forming any linear combinations or observation differences. Details of the implemented IAR approach are described and the performance is analysed for available carrier signal frequencies of different GNSS. Achieved results are compared to the conventional IAR approach based on IF linear combinations and the so called Widelane (WL) and Narrowlane (NL) ambiguities. In addition, the resolution of inter-system integer ambiguities is analysed for common GNSS signal frequencies. The performance of the implemented IAR approach is demonstrated and analysed by the joint Precise Orbit Determination (POD) of multi-GNSS satellites based on fixed multi-frequency carrier phase ambiguities. The improvement of the satellite orbit and clock quality by fixing raw observation ambiguities confirms the successful implementation of the IAR approach based on raw observation processing. Multi-GNSS satellite orbits and clock offsets determined with this approach are compared to results generated with the conventional IF linear combination processing approach and independent external products. This comparison demonstrates an at least equivalent performance of the implemented IAR approach based on raw observation processing. In addition, the fixed raw observation ambiguities are used to investigate and discuss characteristics of multi-GNSS and multi-frequency phase biases.

Blended learning seems an effective solution to knowledge dissemination among the knowledge community in the modern educational context. As the concept of ‘blended learning’ is interpreted differently by individuals, it makes a conceptual and definitional ambiguity among the practitioners over the years. This review tries to establish an insight into terminological and conceptual ambiguity over the definition of blended learning, and it would support scholars to be consistent in defining blended learning in future studies. The review was conducted with 74 research papers published in international peer-reviewed journals accessed via Google Scholar and Scinapse. The findings were thematically analysed in-depth and identified four dimensions of blended learning: Technology, Pedagogy (Educational), Cultural and Social, and Economical. The further analysis of review results could lead into formulating an amenable definition on blended learning - a combination on face-to-face and online instruction which ensure greater flexibility in students’ learning and congruity of course delivery - which is termed as ‘popular sense’ in this paper. Further, it is noted that blended-learning definition often tends to get influenced by contextual and personal experiences of the educationalists.
 Keywords: Blended Learning, Blended Learning Definitions, Technology-integrated Learning