Showing papers on "Encoding (memory) published in 2006"

Is the binding of visual features in working memory resource-demanding?

Abstract: The episodic buffer component of working memory is assumed to play a role in the binding of features into chunks. A series of experiments compared memory for arrays of colors or shapes with memory for bound combinations of these features. Demanding concurrent verbal tasks were used to investigate the role of general attentional processes, producing load effects that were no greater on memory for feature combinations than for the features themselves. However, the binding condition was significantly less accurate with sequential rather than simultaneous presentation, especially for items earlier in the sequence. The findings are interpreted as evidence of a relatively automatic but fragile visual feature binding mechanism in working memory. Implications for the concept of an episodic buffer are discussed.

Variable sector-count ecc

Abstract: Improved memory devices, circuitry, and data methods are described that facilitate the detection and correction of data in memory systems or devices by increasing the data area of user data being covered by the ECC code. This averages any possible bit errors over a larger data area and allows a greater number of errors to be corrected by a combining the ECC codes in the coverage area without substantially changing the overall size of ECC codes being stored over a single sector approach. In one embodiment of the present invention, the size of the data block utilized for ECC coverage is variable and can be selected such that differing areas of the memory array or data types can have a differing ECC data coverage sizes. It is also noted that the ECC algorithm, math base or encoding scheme can also be varied between these differing areas of the memory array.

Soft-input soft-output decoder for nonvolatile memory

Abstract: In a nonvolatile memory system, data is read from a memory array and used to obtain likelihood values, which are then provided to a soft-input soft-output decoder. The soft-input soft-output decoder calculates output likelihood values from input likelihood values and from parity data that was previously added according to an encoding scheme.

Feature bindings endure without attention: Evidence from an explicit recall task

Abstract: Are integrated objects the unit of capacity of visual working memory, or is continued attention needed to maintain bindings between independently stored features? In a delayed recall task, participants reported the color and shape of a probed item from a memory array. During the delay, attention was manipulated with an exogenous cue. Recall was elevated at validly cued positions, indicating that the cue affected item memory. On invalid trials, participants most frequently recalled either both features (perfect object memory) or neither of the two features (no object memory); the frequency with which only one feature was recalled was significantly lower than predicted by feature independence as determined in a single-feature recall task. These data do not support the view that features are remembered independently when attention is withdrawn. Instead, integrated objects are stored in visual working memory without need for continued attention.

Method of Error Correction Coding for Multiple-Sector Pages in Flash Memory Devices

Abstract: A flash memory system, including a flash memory device and a controller, and having improved efficiency error correction coding (ECC), is disclosed. Each page in the flash memory device has the capacity to store multiple sectors' worth of data. However, partial page programming (i.e., followed by a later write to fill the page) is prohibited for reliability reasons. A scratchpad block within the flash memory device is designed, and stores both user data and control data. ECC efficiency is improved by encoding the ECC, or parity, bits over the entire data block corresponding to the user and control data in the page. Retrieval of a particular sector of data requires reading and decoding of the entire page. Especially for codes such as Reed-Solomon and BCH codes, the larger data block including multiple sectors' data improves the error correction capability, and thus enables either fewer redundant memory cells in each page or improved error correction.

Surviving task interruptions: Investigating the implications of long-term working memory theory

Abstract: Typically, we have several tasks at hand, some of which are in interrupted state while others are being carried out. Most of the time, such interruptions are not disruptive to task performance. Based on the theory of Long-Term Working Memory (LTWM; Ericsson, K.A., Kintsch, W., 1995. Long-term working memory. Psychological Review, 102, 211-245), we posit that unless there are enough mental skills and resources to encode task representations to retrieval structures in long-term memory, the resulting memory traces will not enable reinstating the information, which can lead to memory losses. However, once encoded to LTWM, they are virtually safeguarded. Implications of the theory were tested in a series of experiments in which the reading of an expository text was interrupted by a 30-s interactive task, after which the reading was continued. The results convey the remarkably robust nature of skilled memory-when LTWM encoding speed is fast enough for the task-processing imposed by the interface, interruptions have no effect on memory, regardless of their pacing, intensity, or difficulty. In the final experiment where presentation time in the main task was notably speeded up to match the limits of encoding speed, interruptions did hamper memory. Based on the results and the theory, we argue that auditory rehearsal or time-based retrieval cues were not utilized in surviving interruptions and that they are in general weaker strategies for surviving interruptions in complex cognitive tasks. We conclude the paper by suggesting three ways to support interruption tolerance by the means of task and interface design: (1) actively facilitating the development of memory skills, (2) matching encoding speed to task processing demands, and (3) supporting encoding-retrieval symmetry.

Which memory processes are affected in patients with obstructive sleep apnea? An evaluation of 3 types of memory.

Abstract: Study Objective; To investigate which memory processes are affected by obstructive sleep apnea (OSA). Design: Three separate memory systems were investigated in patients with OSA and normal subjects. Verbal episodic memory was tested after forced encoding, in order to control the level of attention during item presentation; procedural memory was tested using a simplified version of a standard test with an interfering task; lastly, working memory was examined with validated paradigms based on a theoretical model. Setting; Sleep laboratory and outpatient sleep clinic in a French tertiary-care university hospital. Participants: Ninety-five patients with OSA and 95 control subjects matched for age and level of education. Group 1 (54 patients, 54 controls) underwent an extensive battery of tasks evaluating verbal episodic, procedural, and working memory. Group 2 (16 patients, 16 controls) underwent procedural memory tests only, and group 3 (25 patients, 25 controls) working memory tests only. Interventions: N/A. Measurements and Results: Compared with matched controls, patients with OSA exhibited a retrieval deficit of episodic memory but intact maintenance, recognition, and forgetfulness; decreased overall performance in procedural memory, although pattern learning did occur; and impairment of specific working memory capabilities despite normal short-term memory. No consistent correlation was found between OSA severity and memory deficit. The long duration of the test session did not negatively impact the patients' performance. Conclusions: Memory impairment in OSA is mild and does not affect all memory processes but, rather, specific aspects, underscoring the need for extensive and specific memory testing in clinical and research settings.

How Color Enhances Visual Memory for Natural Scenes

Abstract: We offer a framework for understanding how color operates to improve visual memory for images of the natural environment, and we present an extensive data set that quantifies the contribution of color in the encoding and recognition phases. Using a continuous recognition task with colored and monochrome gray-scale images of natural scenes at short exposure durations, we found that color enhances recognition memory by conferring an advantage during encoding and by strengthening the encoding-specificity effect. Furthermore, because the pattern of performance was similar at all exposure durations, and because form and color are processed in different areas of cortex, the results imply that color must be bound as an integral part of the representation at the earliest stages of processing.

Understanding Consolidation through the Architecture of Memories

Abstract: Following its encoding, a memory undergoes consolidation. It may be possible to deepen our understanding of the mechanisms supporting consolidation by considering the complex architecture of a memory. Any behavior can be split into multiple components. For example, when learning a new skill we simultaneously learn the movement and the goal of that movement. Each of these components has a distinct representation within a memory. The "off-line" processing of each component may follow different rules, providing an explanation for the variety of performance changes supported by consolidation. By viewing a memory as a representation with multiple components, it is possible to bridge the gap between the behavioral changes, which define consolidation, and the biological mechanisms that support those changes. This is partly because different memory components can be mapped onto different neural circuits. With an increased understanding of consolidation, it may become possible to modulate these off-line processes to improve psychiatric and neurological rehabilitation.

Methods of modulating error correction coding

Abstract: Data is stored in a nonvolatile memory so that different pages of data stored in the same memory cells are encoded according to different encoding schemes. A first page is decoded according to its encoding scheme and an output is provided based on the decoding of the first page that is subsequently used in decoding a second page.

The saturation algorithm for symbolic state-space exploration

Abstract: We present various algorithms for generating the state space of an asynchronous system based on the use of multiway decision diagrams to encode sets and Kronecker operators on boolean matrices to encode the next-state function. The Kronecker encoding allows us to recognize and exploit the “locality of effect” that events might have on state variables. In turn, locality information suggests better iteration strategies aimed at minimizing peak memory consumption. In particular, we focus on the saturation strategy, which is completely different from traditional breadth-first symbolic approaches, and extend its applicability to models where the possible values of the state variables are not known a priori. The resulting algorithm merges “on-the-fly” explicit state-space generation of each submodel with symbolic state-space generation of the overall model.Each algorithm we present is implemented in our tool SmArT. This allows us to run fair and detailed comparisons between them on a suite of representative models. Saturation, in particular, is shown to be many orders of magnitude more efficient in terms of memory and time with respect to traditional methods.

Method and/or system for space-time encoding and/or decoding

Abstract: Time-space encoding and/or decoding may employ time variant linear transformations. Turbo coding and/or decoding may be used in conjunction with the use of time variant linear transformations. Such time variant linear transformations may be unitary in nature.

Nonvolatile memory with modulated error correction coding

Abstract: Data is stored in a nonvolatile memory so that different pages of data stored in the same memory cells are encoded according to different encoding schemes. A first page is decoded according to its encoding scheme and an output is provided based on the decoding of the first page that is subsequently used in decoding a second page.

Systems, masks, and methods for photolithography

Abstract: Photomask patterns are represented using contours defined by mask functions. Given target pattern, contours are optimized such that defined photomask, when used in photolithographic process, prints wafer pattern faithful to target pattern. Optimization utilizes 'merit function' for encoding aspects of photolithographic process, preferences relating to resulting pattern (e.g. restriction to rectilinear patterns), robustness against process variations, as well as restrictions imposed relating to practical and economic manufacturability of photomasks.

Memory Capacity for Sequences in a Recurrent Network with Biological Constraints

Abstract: The CA3 region of the hippocampus is a recurrent neural network that is essential for the storage and replay of sequences of patterns that represent behavioral events. Here we present a theoretical framework to calculate a sparsely connected network's capacity to store such sequences. As in CA3, only a limited subset of neurons in the network is active at any one time, pattern retrieval is subject to error, and the resources for plasticity are limited. Our analysis combines an analytical mean field approach, stochastic dynamics, and cellular simulations of a time-discrete McCulloch-Pitts network with binary synapses. To maximize the number of sequences that can be stored in the network, we concurrently optimize the number of active neurons, that is, pattern size, and the firing threshold. We find that for one-step associations (i.e., minimal sequences), the optimal pattern size is inversely proportional to the mean connectivity c, whereas the optimal firing threshold is independent of the connectivity. If the number of synapses per neuron is fixed, the maximum number P of stored sequences in a sufficiently large, nonmodular network is independent of its number N of cells. On the other hand, if the number of synapses scales as the network size to the power of 3/2, the number of sequences P is proportional to N. In other words, sequential memory is scalable. Furthermore, we find that there is an optimal ratio r between silent and nonsilent synapses at which the storage capacity α = P//[c(1 + r)N] assumes a maximum. For long sequences, the capacity of sequential memory is about one order of magnitude below the capacity for minimal sequences, but otherwise behaves similar to the case of minimal sequences. In a biologically inspired scenario, the information content per synapse is far below theoretical optimality, suggesting that the brain trades off error tolerance against information content in encoding sequential memories.

Adaptive time/frequency-based audio encoding and decoding apparatuses and methods

Abstract: Adaptive time/frequency-based audio encoding and decoding apparatuses and methods. The encoding apparatus includes a transformation & mode determination unit to divide an input audio signal into a plurality of frequency-domain signals and to select a time-based encoding mode or a frequency-based encoding mode for each respective frequency-domain signal, an encoding unit to encode each frequency-domain signal in the respective encoding mode, and a bitstream output unit to output encoded data, division information, and encoding mode information for each respective frequency-domain signal. In the apparatuses and methods, acoustic characteristics and a voicing model are simultaneously applied to a frame, which is an audio compression processing unit. As a result, a compression method effective for both music and voice can be produced, and the compression method can be used for mobile terminals that require audio compression at a low bit rate.

Methods and apparatus for encoding a shared drawing memory

Abstract: A display encoding system is disclosed. The display encoding system includes at least one processor, an encoding circuit, the encoding circuit having a structure separate from the structure of the processor(s), a communication connection to a computer network, a drawing memory, a traffic manager, and a memory access circuit. The processor(s) are configured to execute drawing commands, access the drawing memory via the memory access circuit to store image representation(s) in the drawing memory. The encoding circuit is configured to access the drawing memory to encode at least a portion of the image representation(s) stored in the drawing memory based on the executed drawing commands. The traffic manager is configured to transmit the encoded image over the communication connection to at least one display device.

In-place transformations with applications to encoding and decoding various classes of codes

Abstract: In an encoder for encoding symbols of data using a computing device having memory constraints, a method of performing a transformation comprising loading a source block into memory of the computing device, performing an intermediate transformation of less than all of the source block, then replacing a part of the source block with intermediate results in the memory and then completing the transformation such that output symbols stored in the memory form a set of encoded symbols. A decoder can perform decoding steps in an order that allows for use of substantially the same memory for storing the received data and the decoded source block, performing as in-place transformations. Using an in-place transformation, a large portion of memory set aside for received data can be overwritten as that received data is transformed into decoded source data without requiring a similar sized large portion of memory for the decoded source data.

Self-generated learning in people with multiple sclerosis.

Abstract: Memory impairment is among the most common cognitive deficits in people with multiple sclerosis (MS). To remediate this problem, recent research has evaluated the benefits of self-generated encoding. These nascent investigations reveal that people with MS who have mild memory impairment demonstrate a significant memory benefit from self-generated encoding compared with didactic learning. To extend prior research, the present experiment included MS patients with moderate–severe, rather than just mild, memory impairment. Additionally, the experiment evaluated whether self-generated encoding improves memory for activities of daily living instead of abstract words. Specifically, the experiment determined whether self-generated encoding enhanced memory for names, appointments, and object locations. In agreement with and extending prior research, MS patients remembered more information if it was self-generated rather than didactically presented, and this finding occurred despite moderate–severe memory impairment. Furthermore, compared with didactic encoding, self-generation enhanced recall of activities of daily living. Implications of these findings for cognitive rehabilitation and the nature of memory impairment in MS are discussed (JINS, 2006, 12, 640–648.)

Imagination and false memory inductions: investigating the role of process, content and source of imaginations

Abstract: Three experiments examined the influence of imaginal encoding on false memory rates induced by the Deese-Roediger-McDermott (DRM) paradigm. Several features of imaginal encoding were investigated including the processes giving rise to the images (automatic or deliberate), the source of imagery scripts (participant or another person), and imagery content (e.g. individual or integrated images). Deliberately generating images led to a reduction in false memory rates relative to an imagery control condition. However, the effects on false memory rates very much depended on features characterizing the imaginal encoding. Most notably, when participants (rather than someone else) specified the scripts for guiding their imagery experiences, false memory rates were considerably less. Extending the generality of the distinctiveness heuristic as an explanation for the reduction in false memory rates following pictorial encoding, the results also speak to debates about the wisdom of using guided imagery techniques in applied settings. Copyright © 2006 John Wiley & Sons, Ltd.

Concurrent task effects on memory encoding and retrieval: further support for an asymmetry.

Abstract: Several studies have demonstrated that divided attention at encoding significantly reduces memory performance, whereas divided attention at retrieval affects memory performance only minimally. However, the possibility exists that retrieval processes have shown such resilience because the concurrent tasks used have often not been very demanding. To assess this possibility, we used independent manipulations of the concurrent task during either encoding or retrieval that included stimulus-response compatibility and participant- versus experimenter-controlled pace. In addition, we manipulated the distribution of practice that the participants received with the primary and the concurrent tasks. The results replicated and extended those recently reported by Rohrer and Pashler (2003), indicating that although memory performance is negatively affected by divided attention at retrieval, especially with noncompatible stimulus-response mapping in the concurrent task, this effect was much smaller than that at encoding, in line with the asymmetry notion. Furthermore, experimenter versus participant control of the concurrent task had no effect on memory retrieval. Finally, under conditions of equal practice with both the memory and the concurrent tasks, memory retrieval was affected only to a small degree. In contrast to encoding processes, the processes involved in retrieval accuracy appear, in many cases, to be less interrupted by divided attention, although this protection requires substantial resources.

Signal encoding device and signal encoding method, signal decoding device and signal decoding method, program, and recording medium

Abstract: A signal encoding device for encoding an input time-series signal includes: partitioning means; low-frequency encoding means; high-frequency gain information generating means; low-frequency reference value information generating means; high-frequency gain difference information generating means; high-frequency gain difference information encoding means; and multiplexing means