Effects of Maternal Job Quality on Children\u27s Reading Achievement

I explore the relationship between quality of maternal employment and children’s reading achievement between six to thirteen years of age using data from the Panel Study of Income Dynamics. The hypotheses assert that job quality in terms of level of autonomy, supervisory power, complexity with people, data and things, and family benefits have significant positive effects on children’s reading achievement. The least squares estimates indicate that complexity, power, and autonomy has significant positive effects for children while the effects of family benefits is weak with the exception of the positive effect of union membership for racially disadvantaged groups

Sub-Stream Fairness and Numerical Correctness in MIMO Interference Channels

Signal-to-interference plus noise ratio (SINR) and rate fairness in a system are substantial quality-of-service (QoS) metrics. The acclaimed SINR maximization (max-SINR) algorithm does not achieve fairness between user's streams, i.e., sub-stream fairness is not achieved. To this end, we propose a distributed power control algorithm to render sub-stream fairness in the system. Sub-stream fairness is a less restrictive design metric than stream fairness (i.e., fairness between all streams) thus sum-rate degradation is milder. Algorithmic parameters can significantly differentiate the results of numerical algorithms. A complete picture for comparison of algorithms can only be depicted by varying these parameters. For example, a predetermined iteration number or a negligible increment in the sum-rate can be the stopping criteria of an algorithm. While the distributed interference alignment (DIA) can reasonably achieve sub-stream fairness for the later, the imbalance between sub-streams increases as the preset iteration number decreases. Thus comparison of max-SINR and DIA with a low preset iteration number can only depict a part of the picture. We analyze such important parameters and their effects on SINR and rate metrics to exhibit numerical correctness in executing the benchmarks. Finally, we propose group filtering schemes that jointly design the streams of a user in contrast to max-SINR scheme that designs each stream of a user separately.Comment: To be presented at IEEE ISWTA'1

Transmit Optimization with Improper Gaussian Signaling for Interference Channels

This paper studies the achievable rates of Gaussian interference channels with additive white Gaussian noise (AWGN), when improper or circularly asymmetric complex Gaussian signaling is applied. For the Gaussian multiple-input multiple-output interference channel (MIMO-IC) with the interference treated as Gaussian noise, we show that the user's achievable rate can be expressed as a summation of the rate achievable by the conventional proper or circularly symmetric complex Gaussian signaling in terms of the users' transmit covariance matrices, and an additional term, which is a function of both the users' transmit covariance and pseudo-covariance matrices. The additional degrees of freedom in the pseudo-covariance matrix, which is conventionally set to be zero for the case of proper Gaussian signaling, provide an opportunity to further improve the achievable rates of Gaussian MIMO-ICs by employing improper Gaussian signaling. To this end, this paper proposes widely linear precoding, which efficiently maps proper information-bearing signals to improper transmitted signals at each transmitter for any given pair of transmit covariance and pseudo-covariance matrices. In particular, for the case of two-user Gaussian single-input single-output interference channel (SISO-IC), we propose a joint covariance and pseudo-covariance optimization algorithm with improper Gaussian signaling to achieve the Pareto-optimal rates. By utilizing the separable structure of the achievable rate expression, an alternative algorithm with separate covariance and pseudo-covariance optimization is also proposed, which guarantees the rate improvement over conventional proper Gaussian signaling.Comment: Accepted by IEEE Transactions on Signal Processin

A Gis-Based Campus Information System: Izmir Institute of Technology

In the 21st century, GIS based Campus Information Systems (CIS) have been used by many universities for different aims and become an effective tool. CIS is a wholeness and integrity that is formed by hardware, software, data and users in order to collect spatial and non-spatial data about the university and its sub-units (both academic and administrative), transfer them to computer, store, query, analyze and present the result reports as graphics or non-graphics. In general, the goal of this study is to prepare a GIS-based Izmir Institute of Technology (IIT) CIS. Moreover, after preparing maps of campus area in desired formats, the objectives of the project are to store the maps to plan or update, to provide rapid and easy access to personal and sharable information about campus, to prepare the databases about each department, and to use them for administrative purposes. Therefore, it would have been achieved two main objectives in terms of planning and interactive access for students and staff. At first, by this system, it has been achieved more scientific spatial analyses about land use decisions depending on the natural capacities of the campus site. Then, some negative sides and impacts have been determined relating to the physical developments proposed by the existing campus plan. Thus, it has been achieved crucial results about these defects supporting our initial observations about campus. Secondly, to achieve all information about campus referring spatial or non-spatial by students, academic & administrative staff, and inter-active information access would be created. In order to create CIS for IIT, the spatial and non-spatial data about campus including maps, attribute data were collected; maps, databases, spatial analyses and queries were produced via ArcGIS. At the end of the study, site location of IIT, 1/50000 environmental plan, 1/5000 IIT Master Plan, existing map of campus area, proposed implementation plan of campus area, thematic maps & spatial analyses about topography, geology, soil capability and vegetation and other natural features and suitability analysis for campus site were produced as result productions.

A New Perspective for Saturation Flows at Signalized Intersections

Saturation flow is one of the fundamental parameter that is used to define the level of service, to assign signal timings and other traffic operations. In the conventional approaches (Highway Capacity Manual, Canadian Capacity Guide etc.) base value is adjusted by the parameters that represent field and traffic conditions. Although the results obtained are acceptable, the adjustment parameters may not reflect the field conditions properly in many countries and does not represent any effects on driver behavior. This paper presents a new formula for saturation flow based on driver behavior and some vehicle characteristics. In this formula, mean length, headway and acceleration rates of vehicles, saturation speeds of intersection and mean reaction time of vehicles in a queue are considered. The formula is tested with field data and compared to the values obtained by the HCM, CCG (Canadian Capacity Guide) and the Akcelik approaches. Based on these comparisons, it is commented that estimation of the new formula is promising