Constellation Constrained Capacity of Two-user Broadcast Channels

Capacity region for two-user Gaussian Broadcast Channels (GBC) is well known with the optimal input being Gaussian. In this paper we explore the capacity region for GBC when the users' symbols are taken from finite complex alphabets (like M-QAM, M-PSK). When the alphabets for both the users are the same we show that rotation of one of the alphabets enlarges the capacity region. We arrive at an optimal angle of rotation by simulation. The effect of rotation on the capacity region at different SNRs is also studied using simulation results. Using the setup of Fading Broadcast Channel (FBC) given by [Li and Goldsmith, 2001], we study the ergodic capacity region with inputs from finite complex alphabets. It is seen that, using the procedure for optimum power allocation obtained in [Li and Goldsmith, 2001] for Gaussian inputs, to allocate power to symbols from finite complex alphabets, relative rotation between the alphabets does not improve the capacity region. Simulation results for a modified heuristic power allocation procedure for finite-constellation case, show that Constellation Constrained capacity region enlarges with rotation.

Information Theoretic Results for Three-User Cognitive Channels

In this paper, we introduce the three-user cognitive radio channels with asymmetric transmitter cooperation, and derive achievable rate regions under several scenarios depending on the type of cooperation and decoding capability at the receivers. Two of the most natural cooperation mechanisms for the three-user channel are considered here: cumulative message sharing (CMS) and primary-only message sharing (PMS). In addition to the message sharing mechanism, the achievable rate region is critically dependent on the decoding capability at the receivers. Here, we consider two scenarios for the decoding capability, and derive an achievable rate region for each one of them by employing a combination of superposition and Gel'fand-Pinsker coding techniques. Finally, to provide a numerical example, we consider the Gaussian channel model to plot the rate regions. In terms of achievable rates, CMS turns out to be a better scheme than PMS. However, the practical aspects of implementing such message-sharing schemes remain to be investigated.

STBCs with Reduced Sphere Decoding Complexity for Two-User MIMO-MAC

In this paper, Space-Time Block Codes (STBCs) with reduced Sphere Decoding Complexity (SDC) are constructed for two-user Multiple-Input Multiple-Output (MIMO) fading multiple access channels. In this set-up, both the users employ identical STBCs and the destination performs sphere decoding for the symbols of the two users. First, we identify the positions of the zeros in the R matrix arising out of the Q-R decomposition of the lattice generator such that (i) the worst case SDC (WSDC) and (ii) the average SDC (ASDC) are reduced. Then, a set of necessary and sufficient conditions on the lattice generator is provided such that the R matrix has zeros at the identified positions. Subsequently, explicit constructions of STBCs which results in the reduced ASDC are presented. The rate (in complex symbols per channel use) of the proposed designs is at most 2/N-t where N-t denotes the number of transmit antennas for each user. We also show that the class of STBCs from complex orthogonal designs (other than the Alamouti design) reduce the WSDC but not the ASDC.

Alternative News Sources as 'Collaboratory' Journalism. A case study of Helsingin Sanomat and its relation with the Youth Voice Editorial Board

The new paradigm of connectedness and empowerment brought by the interactivity feature of the Web 2.0 has been challenging the traditional centralized performance of mainstream media. The corporation has been able to survive the strong winds by transforming itself into a global multimedia business network embedded in the network society. By establishing networks, e.g. networks of production and distribution, the global multimedia business network has been able to sight potential solutions by opening the doors to innovation in a decentralized and flexible manner. Under this emerging context of re-organization, traditional practices like sourcing need to be re- explained and that is precisely what this thesis attempts to tackle. Based on ICT and on the network society, the study seeks to explain within the Finnish context the particular case of Helsingin Sanomat (HS) and its relations with the youth news agency, Youth Voice Editorial Board (NÄT). In that sense, the study can be regarded as an explanatory embedded single case study, where HS is the principal unit of analysis and NÄT its embedded unit of analysis. The thesis was able to reach explanations through interrelated steps. First, it determined the role of ICT in HS’s sourcing practices. Then it mapped an overview of the HS’s sourcing relations and provided a context in which NÄT was located. And finally, it established conceptualized institutional relational data between HS and NÄT for their posterior measurement through social network analysis. The data set was collected via qualitative interviews addressed to online and offline editors of HS as well as interviews addressed to NÄT’s personnel. The study concluded that ICT’s interactivity and User Generated Content (UGC) are not sourcing tools as such but mechanism used by HS for getting ideas that could turn into potential news stories. However, when it comes to visual communication, some exemptions were found. The lack of official sources amidst the immediacy leads HS to rely on ICT’s interaction and UGC. More than meets the eye, ICT’s input into the sourcing practice may be more noticeable if the interaction and UGC is well organized and coordinated into proper and innovative networks of alternative content collaboration. Currently, HS performs this sourcing practice via two projects that differ, precisely, by the mode they are coordinated. The first project found, Omakaupunki, is coordinated internally by Sanoma Group’s owned media houses HS, Vartti and Metro. The second project found is coordinated externally. The external alternative sourcing network, as it was labeled, consists of three actors, namely HS, NÄT (professionals in charge) and the youth. This network is a balanced and complete triad in which the actors connect themselves in relations of feedback, recognition, creativity and filtering. However, as innovation is approached very reluctantly, this content collaboration is a laboratory of experiments; a ‘COLLABORATORY’.

Activity–Composition Relations in the Nickel Oxide–Magnesium Oxide System at 1300 K by the Solid-State Galvanic Cell Technique

The activity of NiO in NiO-MgO rock salt solid solution has been measured at 1300 K by employing a solid-state galvanic cell: Pt,Ni+ NiO||(CaO)ZrO2||Ni + (Nix,Mgl-x)O, Pt. A high-density tube of Zr02-15 mol% CaO has been used as the solid electrolyte for the emf measurements. The activities of the component oxides in the rock salt solid solution exhibit negative deviation from ideality at the temperature of investigation. The solid solution obeys regular solution behavior at 1300 K. The value of the regular solution parameter is found to be -12000 ((l000) J mol-1. The composition dependence of ΔGEx obtained in this study agrees reasonably well with the calorimetric data reported in the literature for NiO-MgO solid solution.

Phase relations in the system BiO1.5–SrO–CuO at 1123 K

Phase relations in the system Bi-Sr-Cu-O at 1123 K have been investigated using optical microscopy, electron-probe microanalysis (EPMA) and powder X-ray diffraction (XRD) of equilibrated samples. Differential thermal analysis (DTA) was used to confirm liquid formation for compositions rich in BiO1.5. Compositions along the three pseudo-binary sections and inside the pseudo-ternary triangle have been examined. The attainment of equilibrium was facilitated by the use of freshly prepared SrO as the starting material. The loss of Bi2O3 from the sample was minimized by double encapsulation. A complete phase diagram at 1123 K is presented. It differs significantly from versions of the phase diagram published recently.

Domestic labour relations in India : Vulnerability and gendered life courses in Jaipur

This study explores labour relations between domestic workers and employers in India. It is based on interviews with both employers and workers, and ethnographically oriented field work in Jaipur, carried out in 2004-2007. Combining development studies with gender studies, labour studies, and childhood studies, it asks how labour relations between domestic workers and employers are formed in Jaipur, and how female domestic workers trajectories are created. Focusing on female part-time maids and live-in work arrangements, the study analyses children s work in the context of overall work force, not in isolation from it. Drawing on feminist Marxism, domestic labour relations are seen as an arena of struggle. The study takes an empirical approach, showing class through empiria and shows how paid domestic work is structured and stratified through intersecting hierarchies of class, caste, gender, age, ethnicity and religion. The importance of class in domestic labour relations is reiterated, but that of caste, so often downplayed by employers, is also emphasized. Domestic workers are crucial to the functioning of middle and upper middle class households, but their function is not just utilitarian. Through them working women and housewives are able to maintain purity and reproduce class disctinctions, both between poor and middle classes and lower and upper middle classes. Despite commodification of work relations, traditional elements of service relationships have been retained, particularly through maternalist practices such as gift giving, creating a peculiar blend of traditional and market practices. Whilst employers of part-time workers purchase services in a segmented market from a range of workers for specific, traditional live-in workers are also hired to serve employers round the clock. Employers and workers grudgingly acknowledged their dependence on one another, employers seeking various strategies to manage fear of servant crime, such as the hiring of children or not employing live-in workers in dual-earning households. Paid domestic work carries a heavy stigma and provide no entry to other jobs. It is transmitted from mothers to daughters and working girls were often the main income providers in their families. The diversity of working conditions is analysed through a continuum of vulnerability, generic live-in workers, particularly children and unmarried young women with no close family in Jaipur, being the most vulnerable and experienced part-time workers the least vulnerable. Whilst terms of employment are negotiated informally and individually, some informal standards regarding salary and days off existed for maids. However, employers maintain that workings conditions are a matter of individual, moral choice. Their reluctance to view their role as that of employers and the workers as their employees is one of the main stumbling blocks in the way of improved working conditions. Key words: paid domestic work, India, children s work, class, caste, gender, life course

Phase Relations in the System CaO-Fe2O3-Y2O3 at 1273 K and Compatibility Between Y1-xCaxFeO3-0.5x and Stabilized Zirconia

Phase relations in the system CaO-Fe2O3-Y2O3 in air (P-O2/P-o = 0.21) were explored by equilibrating samples representing eleven compositions in the ternary at 1273 K, followed by quenching to room temperature and phase identification using XRD. Limited mutual solubility was observed between YFeO3 and Ca2Fe2O5. No quaternary oxide was identified. An isothermal section of the phase diagram at 1273 K was constructed from the results. Five three-phase regions and four extended two-phase regions were observed. The extended two-phase regions arise from the limited solid solutions based on the ternary oxides YFeO3 and Ca2Fe2O5. Activities of CaO, Fe2O3 and Y2O3 in the three-phase fields were computed using recently measured thermodynamic data on the ternary oxides. The experimental phase diagram is consistent with thermodynamic data. The computed activities of CaO indicate that compositions of CaO-doped YFeO3 exhibiting good electrical conductivity are not compatible with zirconia-based electrolytes; CaO will react with ZrO2 to form CaZrO3.

Constructing a Community : Myths and Realities of the Open Development Model

The open development model of software production has been characterized as the future model of knowledge production and distributed work. Open development model refers to publicly available source code ensured by an open source license, and the extensive and varied distributed participation of volunteers enabled by the Internet. Contemporary spokesmen of open source communities and academics view open source development as a new form of volunteer work activity characterized by hacker ethic and bazaar governance . The development of the Linux operating system is perhaps the best know example of such an open source project. It started as an effort by a user-developer and grew quickly into a large project with hundreds of user-developer as contributors. However, in hybrids , in which firms participate in open source projects oriented towards end-users, it seems that most users do not write code. The OpenOffice.org project, initiated by Sun Microsystems, in this study represents such a project. In addition, the Finnish public sector ICT decision-making concerning open source use is studied. The purpose is to explore the assumptions, theories and myths related to the open development model by analysing the discursive construction of the OpenOffice.org community: its developers, users and management. The qualitative study aims at shedding light on the dynamics and challenges of community construction and maintenance, and related power relations in hybrid open source, by asking two main research questions: How is the structure and membership constellation of the community, specifically the relation between developers and users linguistically constructed in hybrid open development? What characterizes Internet-mediated virtual communities and how can they be defined? How do they differ from hierarchical forms of knowledge production on one hand and from traditional volunteer communities on the other? The study utilizes sociological, psychological and anthropological concepts of community for understanding the connection between the real and the imaginary in so-called virtual open source communities. Intermediary methodological and analytical concepts are borrowed from discourse and rhetorical theories. A discursive-rhetorical approach is offered as a methodological toolkit for studying texts and writing in Internet communities. The empirical chapters approach the problem of community and its membership from four complementary points of views. The data comprises mailing list discussion, personal interviews, web page writings, email exchanges, field notes and other historical documents. The four viewpoints are: 1) the community as conceived by volunteers 2) the individual contributor s attachment to the project 3) public sector organizations as users of open source 4) the community as articulated by the community manager. I arrive at four conclusions concerning my empirical studies (1-4) and two general conclusions (5-6). 1) Sun Microsystems and OpenOffice.org Groupware volunteers failed in developing necessary and sufficient open code and open dialogue to ensure collaboration thus splitting the Groupware community into volunteers we and the firm them . 2) Instead of separating intrinsic and extrinsic motivations, I find that volunteers unique patterns of motivations are tied to changing objects and personal histories prior and during participation in the OpenOffice.org Lingucomponent project. Rather than seeing volunteers as a unified community, they can be better understood as independent entrepreneurs in search of a collaborative community . The boundaries between work and hobby are blurred and shifting, thus questioning the usefulness of the concept of volunteer . 3) The public sector ICT discourse portrays a dilemma and tension between the freedom to choose, use and develop one s desktop in the spirit of open source on one hand and the striving for better desktop control and maintenance by IT staff and user advocates, on the other. The link between the global OpenOffice.org community and the local end-user practices are weak and mediated by the problematic IT staff-(end)user relationship. 4) Authoring community can be seen as a new hybrid open source community-type of managerial practice. The ambiguous concept of community is a powerful strategic tool for orienting towards multiple real and imaginary audiences as evidenced in the global membership rhetoric. 5) The changing and contradictory discourses of this study show a change in the conceptual system and developer-user relationship of the open development model. This change is characterized as a movement from hacker ethic and bazaar governance to more professionally and strategically regulated community. 6) Community is simultaneously real and imagined, and can be characterized as a runaway community . Discursive-action can be seen as a specific type of online open source engagement. Hierarchies and structures are created through discursive acts. Key words: Open Source Software, open development model, community, motivation, discourse, rhetoric, developer, user, end-user

Water Management in Cambodia Resources and Relations

In Cambodia, water has a special purpose as a source of life and livelihoods. Along with agriculture, fishing and forest use, industry, hydropower, navigation and tourism compete for the water resources. When rights and responsibilities related to essential and movable water are unclear, conflicts emerge easily. Therefore, water management is needed in order to plan and control the use of water resources. The international context is characterized by the Mekong River that flows through six countries. All of the countries by the river have very different roles and interests already depending on their geographical location. At the same time, water is also a tool for cooperation and peace. Locally, the water resources and related livelihoods create base for well-being, for economical and human resources in particular. They in turn are essential for the local people to participate and defend their rights to water use. They also help to construct the resource base of the state administration. Cambodia is highly dependent on the Mekong River. However, Cambodia has a volatile history whose effects can be seen for example in population structure, once suspended public institutions and weakened trust in the society. Relatively stable conditions came to the country as late as in the 1990s, therefore Cambodia for example has a weak status within the Mekong countries. This Master s thesis forms international, national and local interest groups of water use and analyzes their power relations and resources to affect water management. The state is seen as the salient actor as it has the formal responsibility of the water resources and of the coordination between the actions of different levels. In terms of water use this study focuses on production, in management on planning and in power relations on the resources. Water resources of Cambodia are seen consisting of the Mekong River and Tonle Sap Lake and the time span of the study is between the years 1991 and 2006. The material consists of semi-structured interviews collected during summer 2006 in Finland and in Cambodia as well as of literature and earlier studies. The results of the study show that the central state has difficulties to coordinate the actions of different actors because of its resource deficit and internal conflicts. The lessons of history and the vested interests of the actors of the state make it difficult to plan and to strengthen legislation. It seems that the most needed resources at the central state level are intangible as at the village level instead, the tangible resources (fulfilling the basic needs) are primarily important. The local decision-making bodies, NGOs and private sector mainly require legislation and legitimacy to support their role. However, the civil society and the international supporters are active and there are possibilities for new cooperation networks. Keywords: Water management, resources, participation, Cambodia, Mekong

Phase relations and thermodynamic properties of condensed phases in the system calcium-copper-oxygen

The isothermal sections of the phase diagram for the system Ca-Cu-0 at 1073 and 1223 K have been determined. Several compositions in the ternary system were quenched after equilibration, and the phases present were identified by optical microscopy, X-ray diffraction, and electron probe microanalysis. Two ternary compounds Ca2CuO3 and Cao.8&uO1.9s were identified at 1073 K. However, only Ca2CuO3 was found to be stable at 1223 K. The thermodynamic properties of the two ternary compounds were determined using solid-state cells incorporating either an oxide or a fluoride solid electrolyte. The results for both types of cells were internally consistent. The compound C ~ O . ~ & U Ow~h.i~ch~ c, a n also be represented as Ca15Cu18035h, as been identified in an earlier investigation as Cao.828CuOz. Using a novel variation of the galvanic cell technique, in which the emf of a cell incorporating a fluoride electrolyte is measured as a function of the oxygen potential of the gas phase in equilibrium with the condensed phase electrodes, it has been confirmed that the compound Cao.828CuO1.93 (Ca15Cu18035d) oes not have significant oxygen nonstoichiometry. Phase relations have been deduced from the thermodynamic data as a function of the partial pressure of oxygen for the system Ca-Cu-0 at 873, 1073, and 1223 K.

Phase Relations in the System Cu-Gd-O and Gibbs Energy of Formation of CuGd204

The phase relations in the system Cu-Gd-O have been determined at 1273 K by X-ray diffrac- tion, optical microscopy, and electron microprobe analysis of samples equilibrated in quartz ampules and in pure oxygen. Only one ternary compound, CuGd2O4, was found to be stable. The Gibbs free energy of formation of this compound has been measured using the solid-state cell Pt, Cu2O + CuGd2O4 + Gd2O3 // (Y2O3) ZrO2 // CuO + Cu2O, Pt in the temperature range of 900 to 1350 K. For the formation of CuGd2O4 from its binary component oxides, CuO (s) + Gd2O3 (s) → CuGd2O4 (s) ΔG° = 8230 - 11.2T (±50) J mol-1 Since the formation is endothermic, CuGd2O4 becomes thermodynamically unstable with respect to CuO and Gd2O3 below 735 K. When the oxygen partial pressure over CuGd2O4 is lowered, it decomposes according to the reaction 4CuGd2O4 (s) → 4Gd2O3 (s) + 2Cu2O (s) + O2 (g) for which the equilibrium oxygen potential is given by Δμo 2 = −227,970 + 143.2T (±500) J mol−1 An oxygen potential diagram for the system Cu-Gd-O at 1273 K is presented.

Phase relations in the systems Cu–O–R2O3(R = Tm, Lu) and Gibbs energies of formation of Cu2R2O5 compounds

The phase relations in the systems Cu–O–R2O3(R = Tm, Lu) have been determined at 1273 K by X-ray diffraction, optical microscopy and electron probe microanalysis of samples equilibrated in evacuated quartz ampules and in pure oxygen. Only ternary compounds of the type Cu2R2O5 were found to be stable. The standard Gibbs energies of formation of the compounds have been measured using solid-state galvanic cells of the type, Pt|Cu2O + Cu2R2O5+ R2O3‖(Y2O3)ZrO2‖CuO + Cu2O‖Pt in the temperature range 950–1325 K. The standard Gibbs energy changes associated with the formation of Cu2R2O5 compounds from their binary component oxides are: 2CuO(s)+ Tm2O3(s)→Cu2Tm2O5(s), ΔG°=(10400 – 14.0 T/K)± 100 J mol–1, 2CuO(s)+ Lu2O3(s)→Cu2Lu2O5(s), ΔG°=(10210 – 14.4 T/K)± 100 J mol–1 Since the formation is endothermic, the compounds become thermodynamically unstable with respect to component oxides at low temperatures, Cu2Tm2O5 below 743 K and Cu2Lu2O5 below 709 K. When the chemical potential of oxygen over the Cu2R2O5 compounds is lowered, they decompose according to the reaction, 2Cu2R2O5(s)→2R2O3(s)+ 2Cu2O(s)+ O2(g) The equilibrium oxygen potential corresponding to this reaction is obtained from the emf. Oxygen potential diagrams for the Cu–O–R2O3 systems at 1273 K are presented.