An evaluation of child welfare inservice training: The relative effectiveness of substance abuse content in improving worker knowledge and attitudes

Given the seriousness of substance abuse as a child welfare problem, the purpose of this study was to examine the relative effectiveness of an inservice training curriculum for child welfare workers. The training was designed to improve worker knowledge and attitudes in working with substance abusing families. Seventy (70) child welfare workers from public and private agencies in two south Florida counties participated in a pretest/posttest control group design that also trained and retested the control group. The literature review supports that the general preparedness of child welfare workers for the issues presented by substance abusing families is in question. Confounding this problem is a lack of understanding of substance abuse dynamics, worker biases, and predispositions. The two research hypotheses focused on whether inservice training could increase worker knowledge and improve worker attitudes in working with this population. Training delivery was in the form of a five-day inservice focusing on an array of substance abuse knowledge and attitudinal topics. Separate knowledge and attitude instruments were developed for the research and were administered, before and after training, to a purposive sample of participants that were randomly assigned to the experimental and control groups. The data analysis supported the research hypotheses but raised a question. Specifically, the experimental group demonstrated significant improvement in posttest scores on both instruments after receiving the training; whereas the control group, with training withheld, also demonstrated a significant improvement at posttest, but only on the knowledge instrument. Although the question was unanswered, when examined at a more critical significance level, only the experimental group remained significant. The hypotheses were reconfirmed when, after training and retesting, the control group also displayed significant improvement on both instruments. The findings support the conclusion that this substance abuse inservice was effective in improving worker knowledge and attitudes regarding working with substance abusing families. As an implication for social work practice, it suggests that similar inservice training can be a viable training resource when formal substance abuse training is unavailable. Additional research is suggested regarding to what degree increased substance abuse knowledge and improved worker attitudes correlate with improved practice.

Evaluating and improving the opposing expert safeguard against junk science

In Daubert, the Supreme Court opined that opposing expert testimony is an effective safeguard against junk science in the courtroom. Although jurors maybe unable to identify flaws in scientific research without some assistance, social psychological research suggests that people can be trained to make more sophisticated judgments about scientific quality. Further, previous research demonstrated that an opposing expert who addresses the methodology of proffered expert testimony may not enable jurors to evaluate scientific validity. In three studies, I tested why this safeguard was ineffective using a variety of stimulus materials. In the first study, I examined the mediating effect of attitudes on juror decisions within the context of a sexual harassment trial. In the second study, I examined the moderating effect of the presentation of expert credentials on participant decisions regarding child suggestibility literature. In the third study, I tested several improvements to the safeguard using improvements designed to correct for the effects of attitudes and credential presentation on juror decisions within the context of a first-degree murder trial. I found that while opposing expert testimony may have potential as a safeguard, in its current form it is ineffective. That is, a traditional opposing expert caused jurors to be skeptical of all expert testimony rather than sensitizing them to the validity of the research presented at trial. Further, while the improvements tested in this study may have potential to assist jurors in making scientifically sound decisions, more research is needed to further test and refine these improvements. ^

Improving storage performance through layout optimizations

Disk drives are the bottleneck in the processing of large amounts of data used in almost all common applications. File systems attempt to reduce this by storing data sequentially on the disk drives, thereby reducing the access latencies. Although this strategy is useful when data is retrieved sequentially, the access patterns in real world workloads is not necessarily sequential and this mismatch results in storage I/O performance degradation. This thesis demonstrates that one way to improve the storage performance is to reorganize data on disk drives in the same way in which it is mostly accessed. We identify two classes of accesses: static, where access patterns do not change over the lifetime of the data and dynamic, where access patterns frequently change over short durations of time, and propose, implement and evaluate layout strategies for each of these. Our strategies are implemented in a way that they can be seamlessly integrated or removed from the system as desired. We evaluate our layout strategies for static policies using tree-structured XML data where accesses to the storage device are mostly of two kinds—parent-to-child or child-to-sibling. Our results show that for a specific class of deep-focused queries, the existing file system layout policy performs better by 5–54X. For the non-deep-focused queries, our native layout mechanism shows an improvement of 3–127X. To improve performance of the dynamic access patterns, we implement a self-optimizing storage system that performs rearranges popular block accesses on a dedicated partition based on the observed workload characteristics. Our evaluation shows an improvement of over 80% in the disk busy times over a range of workloads. These results show that applying the knowledge of data access patterns for allocation decisions can substantially improve the I/O performance.

Development and verification of control and protection strategies in hybrid AC/DC power systems for smart grid applications

Modern power networks incorporate communications and information technology infrastructure into the electrical power system to create a smart grid in terms of control and operation. The smart grid enables real-time communication and control between consumers and utility companies allowing suppliers to optimize energy usage based on price preference and system technical issues. The smart grid design aims to provide overall power system monitoring, create protection and control strategies to maintain system performance, stability and security. This dissertation contributed to the development of a unique and novel smart grid test-bed laboratory with integrated monitoring, protection and control systems. This test-bed was used as a platform to test the smart grid operational ideas developed here. The implementation of this system in the real-time software creates an environment for studying, implementing and verifying novel control and protection schemes developed in this dissertation. Phasor measurement techniques were developed using the available Data Acquisition (DAQ) devices in order to monitor all points in the power system in real time. This provides a practical view of system parameter changes, system abnormal conditions and its stability and security information system. These developments provide valuable measurements for technical power system operators in the energy control centers. Phasor Measurement technology is an excellent solution for improving system planning, operation and energy trading in addition to enabling advanced applications in Wide Area Monitoring, Protection and Control (WAMPAC). Moreover, a virtual protection system was developed and implemented in the smart grid laboratory with integrated functionality for wide area applications. Experiments and procedures were developed in the system in order to detect the system abnormal conditions and apply proper remedies to heal the system. A design for DC microgrid was developed to integrate it to the AC system with appropriate control capability. This system represents realistic hybrid AC/DC microgrids connectivity to the AC side to study the use of such architecture in system operation to help remedy system abnormal conditions. In addition, this dissertation explored the challenges and feasibility of the implementation of real-time system analysis features in order to monitor the system security and stability measures. These indices are measured experimentally during the operation of the developed hybrid AC/DC microgrids. Furthermore, a real-time optimal power flow system was implemented to optimally manage the power sharing between AC generators and DC side resources. A study relating to real-time energy management algorithm in hybrid microgrids was performed to evaluate the effects of using energy storage resources and their use in mitigating heavy load impacts on system stability and operational security.

Improving Storage Performance Through Layout Optimizations

Disk drives are the bottleneck in the processing of large amounts of data used in almost all common applications. File systems attempt to reduce this by storing data sequentially on the disk drives, thereby reducing the access latencies. Although this strategy is useful when data is retrieved sequentially, the access patterns in real world workloads is not necessarily sequential and this mismatch results in storage I/O performance degradation. This thesis demonstrates that one way to improve the storage performance is to reorganize data on disk drives in the same way in which it is mostly accessed. We identify two classes of accesses: static, where access patterns do not change over the lifetime of the data and dynamic, where access patterns frequently change over short durations of time, and propose, implement and evaluate layout strategies for each of these. Our strategies are implemented in a way that they can be seamlessly integrated or removed from the system as desired. We evaluate our layout strategies for static policies using tree-structured XML data where accesses to the storage device are mostly of two kinds - parent-tochild or child-to-sibling. Our results show that for a specific class of deep-focused queries, the existing file system layout policy performs better by 5-54X. For the non-deep-focused queries, our native layout mechanism shows an improvement of 3-127X. To improve performance of the dynamic access patterns, we implement a self-optimizing storage system that performs rearranges popular block accesses on a dedicated partition based on the observed workload characteristics. Our evaluation shows an improvement of over 80% in the disk busy times over a range of workloads. These results show that applying the knowledge of data access patterns for allocation decisions can substantially improve the I/O performance.

Development and Verification of Control and Protection Strategies in Hybrid AC/DC Power Systems for Smart Grid Applications

Modern power networks incorporate communications and information technology infrastructure into the electrical power system to create a smart grid in terms of control and operation. The smart grid enables real-time communication and control between consumers and utility companies allowing suppliers to optimize energy usage based on price preference and system technical issues. The smart grid design aims to provide overall power system monitoring, create protection and control strategies to maintain system performance, stability and security. This dissertation contributed to the development of a unique and novel smart grid test-bed laboratory with integrated monitoring, protection and control systems. This test-bed was used as a platform to test the smart grid operational ideas developed here. The implementation of this system in the real-time software creates an environment for studying, implementing and verifying novel control and protection schemes developed in this dissertation. Phasor measurement techniques were developed using the available Data Acquisition (DAQ) devices in order to monitor all points in the power system in real time. This provides a practical view of system parameter changes, system abnormal conditions and its stability and security information system. These developments provide valuable measurements for technical power system operators in the energy control centers. Phasor Measurement technology is an excellent solution for improving system planning, operation and energy trading in addition to enabling advanced applications in Wide Area Monitoring, Protection and Control (WAMPAC). Moreover, a virtual protection system was developed and implemented in the smart grid laboratory with integrated functionality for wide area applications. Experiments and procedures were developed in the system in order to detect the system abnormal conditions and apply proper remedies to heal the system. A design for DC microgrid was developed to integrate it to the AC system with appropriate control capability. This system represents realistic hybrid AC/DC microgrids connectivity to the AC side to study the use of such architecture in system operation to help remedy system abnormal conditions. In addition, this dissertation explored the challenges and feasibility of the implementation of real-time system analysis features in order to monitor the system security and stability measures. These indices are measured experimentally during the operation of the developed hybrid AC/DC microgrids. Furthermore, a real-time optimal power flow system was implemented to optimally manage the power sharing between AC generators and DC side resources. A study relating to real-time energy management algorithm in hybrid microgrids was performed to evaluate the effects of using energy storage resources and their use in mitigating heavy load impacts on system stability and operational security.