Signal Constellations for Multilevel Coded Modulation with Sparse Graph Codes

A method to combine error-correction coding and spectral efficient modulation for transmission over channels with Gaussian noise is presented. The method of modulation leads to a signal constellation in which the constellation symbols have a nonuniform distribution. This gives a so-called shape gain which can be as high as e 6 (1:5 dB). A sparse graph code is constructed which is based on a LDPC code and includes the method of modulation. An efficient decoding algorithm can be derived for this sparse graph code. Simulation results show that the performance of the code is quite good compared\ud to other coded modulation schemes proposed in literature

Modulation and coding for quantized channels

We investigate reliable communication over quantized channels from an information theoretical point of view. People seldom consider the effect of quantization in conventional coded modulation systems since Analog-to-Digital (AD) converters used in these systems always have high resolution, e.g. 2/3 source bits are often quantized into 10/12 bits. However, AD converters with a high resolution are power consuming. In this paper, we present a scheme to design an optimum quantizer with low resolution which can be used to communicate over the quantized channel. Moreover, we show that reliable transmission over the Additive White Gaussian Noise (AWGN) channel at a rate of R bit/use is possible with R + 1 or R + 2 quantized bits.\u

On the design of a wireless multi-antenna monitoring system

In this paper we investigate the design of a wireless monitoring system. This system consists of several wireless monitoring units, each transmitting data collected from sensors. This data is received and processed at a central control unit. The typical operating environment poses several challenges. The channel’s delay spread is substantial and the distance between receiver and transmitter is in the order of 400 meters. In order to guarantee reliable communication, we combine multi-antenna techniques (spacetime block coding) with strong coding (LDPC codes). The cost and complexity of the monitoring units is kept low, and most of the processing is performed on the central control unit. We present a system design for the monitoring units and show simulation results

A continuum model accounting for the effect of the initial and evolving microstructure on the evolution of dynamic recrystallization

Laser assisted forming is a process which is increasingly being adopted by the industry. Application of heat by a laser to austenitic stainless steel (ASS) sheet provides local control over formability and strength of the material. The hot forming behavior of ASS is characterized by significant dynamic recovery and dynamic recrystallization. These two processes lead to a softening stress-strain response and have a significant impact on the microstructure of the material. Most of the research performed on hot forming of ASS focuses on dynamic recrystallization and then specifically on the behavior of the annealed state, consisting of relatively large equiaxed austenite grains. However, in industry it is common to use cold rolled ASS sheet which is a mixture of austenite and martensite. Application of a laser heat treatment to the cold rolled grades of ASS induces a socalled ‘reverse’ transformation of martensite to austenite which, depending on the exact time-temperature combinations, leads to an austenite grain size in the range of nanoto micrometer. It is known from experiments that the effect of initial grain size on dynamic recrystallization is significant, especially on the initial stages of recrystallization. Therefore any continuum model capable of describing hot forming of cold rolled ASS should include the effect of the initial grain size. In this work a physically based continuum model for dynamic recrystallization is presented which accounts for the effect of the initial and evolving grain size on the evolution of dynamic recrystallization. It is shown that the initial grain size can be accounted for by incorporating its effect on the availability of preferred nucleation sites, i.e. grain edges. The new model is compared to experimental results and it is shown that the model correctly predicts accelerated recrystallization with decrease in grain size and that there is a weak dependence of the dynamically recrystallized grain size on the initial grain size. Furthermore predicted recrystallized grain sizes are in good agreement with the experimentally measured values

On the Performance of a Multi-Edge Type LDPC Code for Coded Modulation

We present an error-correcting code which merges error-correction and modulation. The code is an extension of a Low-Density Parity-Check (LDPC) code, and can be viewed as a multi-edge type LDPC code. The symbols of the codewords are from a ternary alphabet, and have a different probability of occurrence. When the code is used on the complex Additive White Gaussian Noise (AWGN) channel, the spectral efficiency is 2 bit/s/Hz. Therefore, the code is suitable for bandwidth-efficient communication. Simulations on the AWGN channel show that the code outperforms several other coded modulation schemes proposed in literature

ED to Telemetry Bed: Optimizing Nurse Communication & Decreasing Team Frustration

PROBLEM: According to the Institute of Medicine, boarding inpatients in the emergency department (ED) can result in an increased risk for medical errors, delay in treatments, and decreased quality of care. The goal is to move the patient to the hospital bed within 60 minutes from when an order is written for admission. The current average monthly compliance for ED throughput and admission to the inpatient bed is at 45% compared to the target of 70%. Lack of standardization during handoff can lead to delays, miscommunication and causes team frustration. CONTEXT: In 2022, this community hospital’s ED microsystem had limited capacity, and increased ED volume compared to 2021. The hospital measures ED admissions to inpatient bed as a performance metric. One microsystem and one shift on a telemetry (tele) unit were identified to test and analyze new approaches to reduce delays, optimize nurse communication, decrease team frustration, and create a realistic business case. A 15% improvement was projected to yield an increase in efficiency by $60,346.44 for the tele unit. The ED’s loss for six months was estimated at$1,011,832.70 so a 15% improvement could yield a benefit of $151,774.90. INTERVENTIONS: In-person hand-off between the ED and the telemetry nurse was implemented. Team Strategies and Tools to Enhance Performance and Patient Safety (TeamSTEPPS) evidence-based tool SBAR (Situation, Background, Assessment, Recommendation) was adopted to standardize reporting. The change was initially implemented on one shift, utilizing small test cycles, and was later established as a standard of communication on all shifts. MEASURES: The primary outcome measure was to track the ED to bed metric before and after each test of change with a target of 15% improvement over six months. The process measure included measuring nurse satisfaction with the current handoff process and the rate of compliance with the use of the SBAR tool on one shift (evenings). By July 1st, 2022, 65% of admissions on the second shift on the Telemetry unit were to experience a 1:1 handoff between the ED and the Telemetry nurse within 60 minutes from the time admit order is written utilizing the standardized TeamSTEPPS SBAR tool. RESULTS: Over six months, the practice change resulted in partial improvement. The time it took for the patient to leave the ED, from when the bed was assigned, decreased from 76 minutes to 26 minutes from January to April 2022. Interim data indicates the overall outcome measure remained unchanged at 45%. Standardization led to the timely start of care interventions on the telemetry unit leading to increased care team satisfaction. CONCLUSION: A Clinical Nurse Leader can effectively lead and collaborate between different microsystems to test and implement evidence-based tools and strategies to improve clinical, staff, and operational outcomes

Embracing panarchy, building resilience and integrating adaptive management through a rebirth of the National Environmental Policy Act

Environmental law plays a key role in shaping policy for sustainability of socialeecological systems. In particular, the types of legal instruments, institutions, and the response of law to the inherent variability in socialeecological systems are critical. Sustainability likely must occur via the institutions we have in place, combined with alterations in policy and regulation within the context of these institutions. This ecosystem management arrangement can be characterized as a panarchy, with research on sustainability specific to the scale of interest. In this manuscript we examine an opportunity for integrating these concepts through a regulatory rebirth of the National Environmental Policy Act (NEPA). NEPA currently requires federal agencies to take a “hard look” at the environmental consequences of proposed action. The original intent of NEPA, however, was more substantive and its provisions, while currently equilibrium based, may be reconfigured to embrace new understanding of the dynamics of socialeecological systems