13 resultados para passive intermodulation

em Helda - Digital Repository of University of Helsinki


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This thesis consists of three articles on passive vector fields in turbulence. The vector fields interact with a turbulent velocity field, which is described by the Kraichnan model. The effect of the Kraichnan model on the passive vectors is studied via an equation for the pair correlation function and its solutions. The first paper is concerned with the passive magnetohydrodynamic equations. Emphasis is placed on the so called "dynamo effect", which in the present context is understood as an unbounded growth of the pair correlation function. The exact analytical conditions for such growth are found in the cases of zero and infinite Prandtl numbers. The second paper contains an extensive study of a number of passive vector models. Emphasis is now on the properties of the (assumed) steady state, namely anomalous scaling, anisotropy and small and large scale behavior with different types of forcing or stirring. The third paper is in many ways a completion to the previous one in its study of the steady state existence problem. Conditions for the existence of the steady state are found in terms of the spatial roughness parameter of the turbulent velocity field.

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Expressing generalized-personal meaning in Russian Based on data from Russian, this doctoral dissertation examines generalized-personal meaning that is, generic expressions referring to all human beings, people in general, each or any person (e.g. S vozrastom načinae cenit prostye ve či With age you start to appreciate simple things ). The study shares its basic theoretical orientation with functional approaches going from meaning to form . The objective of the thesis is to determine and describe the various linguistic means which can be used by the speaker to express generalized-personal meaning. The main material of the study consists of 2,000 examples collected from modern Russian literature, newspapers, and magazines. The linguistic means of expressing generalized-personal meaning are divided into three main classes. Morphological and lexico-grammatical means (22% of the material) include the use of personal pronouns and personal verbal endings. In Russian, all personal forms except the 3rd person singular can be used in a generalized-personal meaning. Lexical means (14% of the material) involve, above all, pronouns like vse all , ka dyj everyone , nikto no one , as well as the nouns čelovek man and ljudi people . In emotional speech, generalized-personal meaning can also be conveyed lexically by using utterances like da e idiot znaet even an idiot knows . In rhetorical questions the pronoun kto who can appear in this meaning (cf. Kto ne ljubit moro enoe?! Who doesn t like ice cream?! ). The third main class, syntactic means (64% of the material), consists of constructions in which the generic person is not expressed at the surface level. This class mainly includes two-component structures in which the infinitive relates to a modal predicative adverb (e.g. mo no can, be allowed to , nado must ), modal verb (e.g. stoit be worth(while) , sleduet must, be obliged to ), or predicative adverb ending in -о (e.g. trudno it is hard to , neprilično is not appropriate ). Other syntactic means are: one-component infinitive structures, so-called embedded structures, structures with a processual noun, passive constructions, and gerund constructions. The different forms of expression available in Russian are not interchangeable in all contexts. Even if a given context tolerates the substitution of one construction for another, the two expressions are never entirely synonymous. In addition to determining the range of forms which can express generalized-personal meaning, the study aims to compare these forms and to specify the conditions and possible restrictions (contextual, semantic, syntactic, stylistic, etc.) associated with the use of each construction. In Russian linguistics, the generalized-personal meaning has not been extensively studied from a functional perspective. The advantage of a meaning-based functional approach is that it gives a comprehensive picture of the diversity and distribution of the phenomenon.

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"We have neither Eternal Friends nor Eternal Enemies. We have only Eternal Interests .Finland's Relations with China 1949-1989 The study focuses on the relations between Finland and the People s Republic of China from 1949-1989 and examines how a small country became embroiled in international politics, and how, at the same time, international politics affected Finnish-Chinese relations and Finland s China policy formulation. The study can be divided into three sections: relations during the early years, 1949-1960, before the Chinese and Soviet rift became public; the relations during the passive period during the 1960s and 1970s; and the impact of China s Open Door policy on Finland s China policy from 1978-1989. The diplomatically challenging events around Tiananmen Square and the reactions which followed in Finland bring the study to a close. Finland was among the first Western countries to recognise the People s Republic and to establish diplomatic relations with her, thereby giving Finland an excellent position from which to further develop good relations. Finland was also the first Western country to sign a trade agreement with China. These two factors meant that Finland was able to enjoy a special status with China during the 1950s. The special status was further strengthened by the systematic support of the government of Finland for China's UN membership. The solid reputation earned in the 1950s had to carry Finland all the way through to the 1980s. For the two decades in between, during the passive policy period of the 1960s and 1970s, relations between Finland and the Soviet Union also determined the state of foreign relations with China. Interestingly, however, it appeared that President Urho Kekkonen was encouraged by Ambassador Joel Toivola to envisage a more proactive policy towards China, but the Cultural Revolution cut short any such plan for nearly twenty years. Because of the Soviet Union, Finland held on to her passive China policy, even though no such message was ever received from the Soviet Union. In fact, closer relationships between Finland and China were encouraged through diplomatic channels. It was not until the presidency of Mauno Koivisto that the first high-level ministerial visit was made to China when, in 1984, Foreign Minister Paavo Väyrynen visited the People s Republic. Finnish-Chinese relations were lifted to a new level. Foreign Minister Väyrynen, however, was forced to remove the prejudices of the Chinese. In 1985, when the Speaker of the Finnish Parliament, Erkki Pystynen visited China he also discovered that Finland s passive China policy had caused misunderstandings amongst the Chinese politicians. The number of exchanges escalated in the wake of the ground-breaking visit by Foreign Minister Väyrynen: Prime Minister Kalevi Sorsa visited China in 1986 and President Koivisto did so in 1988. President Koivisto stuck to practical, China-friendly policies: his correspondence with Li Peng, the attitude taken by the Finnish government after the Tiananmen Square events and the subsequent choices made by his administration all pointed to a new era in relations with China.

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Dissertation considers the birth of modernist and avant-gardist authorship as a reaction against mass society and massculture. Radical avant-gardism is studied as figurative violence done against the human form. The main argument claims avant-gardist authorship to be an act of masculine autogenesis. This act demands human form to be worked to an elementary state of disarticulateness, then to be reformed to the model of the artist's own psychophysical and idiosyncratic vision and experience. This work is connected to concrete mass, mass of pigment, charcoal, film, or flesh. This mass of the figure is worked to create a likeness in the nervous system of the spectator. The act of violence against the human figure is intended to shock the spectator. This shock is also a state of emotional and perceptional massification. I use theatrical image as heuristic tool and performance analysis, connecting figure and spectator into a larger image, which is constituted by relationships of mimesis, where figure presents the likeness of the spectator and spectator the likeness of the figure. Likeness is considered as both gestural - social mimetic - and sensuous - kinesthetically mimetic. Through this kind of construction one can describe and contextualize the process of violent autogenesis using particular images as case studies. Avant-gardist author is the author of theatrical image, not particular figure, and through act of massification the nervous system of the spectator is also part of this image. This is the most radical form and ideology of avant-gardist and modernist authorship or imagerial will to power. I construct a model of gestural-mimic performer to explicate the nature of violence done for human form in specific works, in Mann's novella Death in Venice, in Schiele's and Artaud's selfportaits, in Francis Bacon's paintings, in Beckett's shortplat NOT I, in Orlan's chirurgical performance Operation Omnipresense, in Cindy Sherman's Film/Stills, in Diamanda Galás's recording Vena Cava and in Hitchcock's Psycho. Masspsychology constructed a phobic picture of human form's plasticity and capability to be constituted by influencies coming both inside and outside - childhood, atavistic organic memories, urban field of nervous impulses, unconsciousness, capitalist (image)market and democratic masspolitics. Violence is then antimimetic and antitheatrical, a paradoxical situation, considering that massmedias and massaudiences created an enormous fascination about possibilities of theatrical and hypnotic influence in artistic elites. The problem was how to use theatrical image without coming as author under influence. In this work one possible answer is provided: by destructing the gestural-mimetic performer, by eliminating representations of mimic body techniques from the performer of human (a painted figure, a photographed figure, a filmed figure or an acted figure, audiovisual or vocal) figure. This work I call the chirurgical operation, which also indicates co-option with medical portraitures or medico-cultural diagnoses of human form. Destruction of the autonomy of the performer was a parallel process to constructing the new mass media audience as passive, plastic, feminine. The process created an image of a new kind of autotelic masculine author-hero, freed from human form in its bourgeois, aristocratic, classical and popular versions.

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In the research on the Continuation War, interest in the events themselves had exceeded the interest in military planning. Careful consideration has not been given to the planning process and the options that were available. This study shows how the planning of these operations was carried out and identifies the persons responsible. Contrary to earlier research this study shows that persons other than Field-Marshal Carl Gustaf Mannerheim and Quartermaster-General Aksel Airo took part in the planning. Furthermore, the plan was to carry out the operations further east than was ultimately done. The operation plans were coordinated by the Operations Department of Headquarters, which had the opportunity to influence on both Mannerheim and Airo. Part of the actual planning was made outside Headquarters, but final decisions were taken at Headquarters. It is worth observing that many times Mannerheim asked President Risto Ryti for his opinion concerning these operations. The Germans tried to influence the Finnish plans, but the Finns took their decisions independently, although they took German requests into account. It is well-known that the attack by the Finnish forces was stopped at the end of the year 1941. It is less well-known that the Finns planned new attacks until the autumn of 1942. At that point the Finns were convinced that the Germans would lose the war. The Finns were thus prepared to keep advancing should the Germans progress in the direction of Leningrad. This study shows that the Finnish military leaders worked for Finland s own plans and their cooperation with the Germans was directed to achieving this goal. In other words, Finland tried expand eastward with the help of the Germans. This purpose was particularly evident in the planning of the operations in the Hanko district and the Karelian Isthmus in the summer and autumn of 1941, in the Sorokka district in the spring of 1942 and around Lake Ladoga in the summer and autumn of 1942. The Finns reduced their activities when Germans took over responsibility for the operations. However, at the same time the Finns tried to support Germans in passive ways. The Finns justified the decrease in their activities with lack of Finnish forces and numerous defeats. Earlier research has shown that Finland was an active operator in the Continuation War and tried to take back the areas lost in the Winter War. In this study that view becomes more precise and clear especially with regard to Field-Marshal Mannerheim and other high military leaders. There is clear indication that the Finns would have attacked much further east had a German success made such an attack possible.

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Poetics of Awakenings. Genres and Intertexts in Arvid Järnefelt s Novels Isänmaa, Maaemon lapsia and Veneh ojalaiset This doctoral dissertation focuses on Arvid Järnefelt s (1961 1932) novels Isänmaa (1893), Maaemon lapsia (1905) and Veneh ojalaiset (1909). The study applies the genre theory and concepts Alastair Fowler has introduced in his Kinds of Literature (1982). Fowler s theory of the novel is developed further and applied to Finnish realist novels. The generic analysis is supplemented by intertextual analysis, which is mainly based on the idea of specific intertextual relations as presented by Kiril Taranovsky. Generic and intertextual analyses form the basis for hermeneutic interpretation, in which attention is paid to the fact that the novels are written by the designated writer in specific historical and cultural circumstances. Instead of the author s intention , the study focuses on the realised intention , in other words the novels as they are published. Järnefelt s first novel Isänmaa is understood to be a classical Bidungsroman that depicts the socialisation of a young male protagonist. From an intertextual point of view, the novel appears to be a novel of conversion, too, due to the biblical allusions concealed in the depiction of the events. Furthermore, Isänmaa is seen to stand in an intertextual relation to Hegel s, Snellman s and Topelius s writings. Maaemon lapsia is argued to be a thesis novel, which persuades the reader to adopt a certain ideological and political stance, namely Henry George s view on the private ownership of land. The novel is modulated by the generic repertoires of fairy tale and tragedy. The mythical frame of the novel supports the thesis novel, as it gives universal validity to the particular events depicted in the novel. Maaemon lapsia also comments on the contemporary political debate on the relations between Finland and Russia by presenting the relationship as analogous to the relationship between tenant farmer and landowner. Veneh ojalaiset exhibits a wide range of genres. Comic, tragic and mythical mode is combined with, for example, family novel, romance, conversion novel and revolutionary novel. From a rhetorical viewpoint, the novel is an apology, which accuses society of generating criminality by means of unjust laws and procedures. The novel discusses the question of resistance to evil by using the themes of Faust and Job, as well as by confronting the philosophies of Epictetus and Nietzsche. The novel is a thesis novel, which disputes the possibility of violent revolution as a way to a better society and recommends passive resistance for an individual living in an unjust society. The poetics of Järnefelt s novels is regarded as the poetics of conversion, as all the novels in focus depict the protagonist s awakening to see the society in a new light, be it a patriotic vision of the reality or a conception of the unfairness of society.

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Pitch discrimination is a fundamental property of the human auditory system. Our understanding of pitch-discrimination mechanisms is important from both theoretical and clinical perspectives. The discrimination of spectrally complex sounds is crucial in the processing of music and speech. Current methods of cognitive neuroscience can track the brain processes underlying sound processing either with precise temporal (EEG and MEG) or spatial resolution (PET and fMRI). A combination of different techniques is therefore required in contemporary auditory research. One of the problems in comparing the EEG/MEG and fMRI methods, however, is the fMRI acoustic noise. In the present thesis, EEG and MEG in combination with behavioral techniques were used, first, to define the ERP correlates of automatic pitch discrimination across a wide frequency range in adults and neonates and, second, they were used to determine the effect of recorded acoustic fMRI noise on those adult ERP and ERF correlates during passive and active pitch discrimination. Pure tones and complex 3-harmonic sounds served as stimuli in the oddball and matching-to-sample paradigms. The results suggest that pitch discrimination in adults, as reflected by MMN latency, is most accurate in the 1000-2000 Hz frequency range, and that pitch discrimination is facilitated further by adding harmonics to the fundamental frequency. Newborn infants are able to discriminate a 20% frequency change in the 250-4000 Hz frequency range, whereas the discrimination of a 5% frequency change was unconfirmed. Furthermore, the effect of the fMRI gradient noise on the automatic processing of pitch change was more prominent for tones with frequencies exceeding 500 Hz, overlapping with the spectral maximum of the noise. When the fundamental frequency of the tones was lower than the spectral maximum of the noise, fMRI noise had no effect on MMN and P3a, whereas the noise delayed and suppressed N1 and exogenous N2. Noise also suppressed the N1 amplitude in a matching-to-sample working memory task. However, the task-related difference observed in the N1 component, suggesting a functional dissociation between the processing of spatial and non-spatial auditory information, was partially preserved in the noise condition. Noise hampered feature coding mechanisms more than it hampered the mechanisms of change detection, involuntary attention, and the segregation of the spatial and non-spatial domains of working-memory. The data presented in the thesis can be used to develop clinical ERP-based frequency-discrimination protocols and combined EEG and fMRI experimental paradigms.

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Distraction in the workplace is increasingly more common in the information age. Several tasks and sources of information compete for a worker's limited cognitive capacities in human-computer interaction (HCI). In some situations even very brief interruptions can have detrimental effects on memory. Nevertheless, in other situations where persons are continuously interrupted, virtually no interruption costs emerge. This dissertation attempts to reveal the mental conditions and causalities differentiating the two outcomes. The explanation, building on the theory of long-term working memory (LTWM; Ericsson and Kintsch, 1995), focuses on the active, skillful aspects of human cognition that enable the storage of task information beyond the temporary and unstable storage provided by short-term working memory (STWM). Its key postulate is called a retrieval structure an abstract, hierarchical knowledge representation built into long-term memory that can be utilized to encode, update, and retrieve products of cognitive processes carried out during skilled task performance. If certain criteria of practice and task processing are met, LTWM allows for the storage of large representations for long time periods, yet these representations can be accessed with the accuracy, reliability, and speed typical of STWM. The main thesis of the dissertation is that the ability to endure interruptions depends on the efficiency in which LTWM can be recruited for maintaing information. An observational study and a field experiment provide ecological evidence for this thesis. Mobile users were found to be able to carry out heavy interleaving and sequencing of tasks while interacting, and they exhibited several intricate time-sharing strategies to orchestrate interruptions in a way sensitive to both external and internal demands. Interruptions are inevitable, because they arise as natural consequences of the top-down and bottom-up control of multitasking. In this process the function of LTWM is to keep some representations ready for reactivation and others in a more passive state to prevent interference. The psychological reality of the main thesis received confirmatory evidence in a series of laboratory experiments. They indicate that after encoding into LTWM, task representations are safeguarded from interruptions, regardless of their intensity, complexity, or pacing. However, when LTWM cannot be deployed, the problems posed by interference in long-term memory and the limited capacity of the STWM surface. A major contribution of the dissertation is the analysis of when users must resort to poorer maintenance strategies, like temporal cues and STWM-based rehearsal. First, one experiment showed that task orientations can be associated with radically different patterns of retrieval cue encodings. Thus the nature of the processing of the interface determines which features will be available as retrieval cues and which must be maintained by other means. In another study it was demonstrated that if the speed of encoding into LTWM, a skill-dependent parameter, is slower than the processing speed allowed for by the task, interruption costs emerge. Contrary to the predictions of competing theories, these costs turned out to involve intrusions in addition to omissions. Finally, it was learned that in rapid visually oriented interaction, perceptual-procedural expectations guide task resumption, and neither STWM nor LTWM are utilized due to the fact that access is too slow. These findings imply a change in thinking about the design of interfaces. Several novel principles of design are presented, basing on the idea of supporting the deployment of LTWM in the main task.

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I studied discussions during development project. Aim of the study was to analyse, what way workers represented their work: how normalized way of interpretation myths appeared in discourse and what consequences these utterances caused to drift of discussion. Change laboratory, which is a development method, is based to developmental work research methodology. Development is designed to be successful by learning activity and learning acts. Preventing factors of learning have been studied widely. Research has leaned to concept of resistance to change. Phenomenon of learning has been interpreted to be successful only if everybody has an agreement about the situation. There is also a new kind of concept of resistance. Resistance can be seen as a part of learning, normal processing of the learning activity. Another preventing factor can be seen as disorders of discourse, which are verbal ways of telling something that aren t real. Theoretically I consider these verbal ways as myth interpretations, which can be used as argumentative tools. I used analysis of discourse as an analytical method. Results of analysis revealed four different myth interpretations in workers discussions. Character of work was been described with myths unforeseen situations and disturbances are normal . Work was also described to be functional with myths system works and workers cause disturbances . Change laboratory discussions can be described as different social languages, which caused diverse perspectives to workers and researchers representations. Social languages also affected the way people analysed disturbances and system. Critical phase of change laboratory method seems to be analysis of disturbances and planning new mode of action. Myth utterances were used to reject ways of developing, analysis of system level and need of development. Myth utterances worked three different ways: ineffective, active or passive.

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Tämän itsenäisistä osatutkimuksista koostuvan tutkimussarjan tavoitteena oli pyrkiä täydentämään kuvaa matemaattisilta taidoiltaan heikkojen lasten ja nuorten tiedonkäsittelyvalmiuksista selvittämällä, ovatko visuaalis-spatiaaliset työmuistivalmiudet yhteydessä matemaattiseen suoriutumiseen. Teoreettinen viitekehys rakentui Baddeleyn (1986, 1997) kolmikomponenttimallin ympärille. Työmuistikäsitys oli kuitenkin esikuvaansa laajempi sisällyttäen visuaalis-spatiaaliseen työmuistiin Cornoldin ja Vecchin (2003) termein sekä passiiviset varastotoiminnot että aktiiviset prosessointitoiminnot. Yhteyksiä työmuistin ja matemaattisten taitojen välillä tarkasteltiin viiden eri osatutkimuksen avulla. Kaksi ensimmäistä keskittyivät alle kouluikäisten lukukäsitteen hallinnan ja visuaalis-spatiaalisten työmuistivalmiuksen tutkimiseen ja kolme jälkimmäistä peruskoulun yhdeksäsluokkalaisten matemaattisten taitojen ja visuaalis-spatiaalisten työmuistitaitojen välisten yhteyksien selvittämiseen. Tutkimussarjan avulla pyrittiin selvittämään, ovatko visuaalis-spatiaaliset työmuistivalmiudet yhteydessä matemaattiseen suoriutumiseen sekä esi- että yläkouluiässä (osatutkimukset I, II, III, IV, V), onko yhteys spesifi rajoittuen tiettyjen visuaalis-spatiaalisten valmiuksien ja matemaattisen suoriutumisen välille vai onko se yleinen koskien matemaattisia taitoja ja koko visuaalis-spatiaalista työmuistia (osatutkimukset I, II, III, IV, V) tai työmuistia laajemmin (osatutkimukset II, III) sekä onko yhteys työmuistispesifi vai selitettävissä älykkyyden kaltaisella yleisellä päättelykapasiteetilla (osatutkimukset I, II, IV). Tutkimussarjan tulokset osoittavat, että kyky säilyttää ja käsitellä hetkellisesti visuaalis-spatiaalista informaatiota on yhteydessä matemaattiseen suoriutumiseen eikä yhteyttä voida selittää yksinomaan joustavalla älykkyydellä. Suoriutuminen visuaalis-spatiaalista työmuistia mittaavissa tehtävissä on yhteydessä sekä alle kouluikäisten esimatemaattisten taitojen hallintaan että peruskoulun yhdeksäsluokkalaisten matematiikan taitoihin. Matemaattisilta taidoiltaan heikkojen lasten ja nuorten visuaalis-spatiaalisten työmuistiresurssien heikkoudet vaikuttavat kuitenkin olevan sangen spesifejä rajoittuen tietyntyyppisissä muistitehtävissä vaadittaviin valmiuksiin; kaikissa visuaalis-spatiaalisen työmuistin valmiuksia mittaavissa tehtävissä suoriutuminen ei ole yhteydessä matemaattisiin taitoihin. Työmuistivalmiuksissa ilmenevät erot sekä alle kouluikäisten että kouluikäisten matemaattisilta taidoiltaan heikkojen ja normaalisuoriutujien välillä näyttävät olevan kuitenkin jossain määrin yhteydessä kielellisiin taitoihin viitaten vaikeuksien tietynlaiseen kasautumiseen; niillä matemaattisesti heikoilla, joilla on myös kielellisiä vaikeuksia, on keskimäärin laajemmat työmuistiheikkoudet. Osalla matematiikassa heikosti suoriutuvista on näin ollen selvästi keskimääräistä heikommat visuaalis-spatiaaliset työmuistivalmiudet, ja tämä heikkous saattaa olla yksi mahdollinen syy tai vaikeuksia lisäävä tekijä heikon matemaattisen suoriutumisen taustalla. Visuaalis-spatiaalisen työmuistin heikkous merkitsee konkreettisesti vähemmän mentaalista prosessointitilaa, joka rajoittaa oppimista ja suoritustilanteita. Tiedonkäsittelyvalmiuksien heikkous liittyy nimenomaan oppimisnopeuteen, ei asioiden opittavuuteen sinänsä. Mikäli oppimisympäristö ottaa huomioon valmiuksien rajallisuuden, työmuistiheikkoudet eivät todennäköisesti estä asioiden oppimista sinänsä. Avainsanat: Työmuisti, visuaalis-spatiaalinen työmuisti, matemaattiset taidot, lukukäsite, matematiikan oppimisvaikeudet