Letter from the Editor

For the seventh time, the Gettysburg Historical Journal of Gettysburg College put out a call for the submissions to the annual journal, and once again, the Journal received a large number of outstanding student compositions on the topic of history. This year in particular, the editorial board faced a daunting task in deciding which submissions were the best of the best

Portrait of Philip H. Glatfelter in Glatfelter Hall

The first floor lobby of Glatfelter Hall is home to a Ned Bittinger oil painting portrait of Philip H. Glatfelter, the namesake of the building. Bittinger was commissioned in 1988 to paint the portraits of several Gettysburg College benefactors. Philip H. Glatfelter’s generosity to Gettysburg College was never ending. In a forty year period, P.H. Glatfelter, his son William L. Glatfelter, and their immediate family gave $225,000 to Gettysburg College. At the time of his death in 1907, he was considered “one of the best friends, if not the best, that Gettysburg College ever had.” [excerpt] Course Information: Course Title: HIST 300: Historical Method Academic Term: Spring 2006 Course Instructor: Dr. Michael J. Birkner \u2772 Hidden in Plain Sight is a collection of student papers on objects that are hidden in plain sight around the Gettysburg College campus. Topics range from the Glatfelter Hall gargoyles to the statue of Eisenhower and from historical markers to athletic accomplishments. You can download the paper in pdf format and click View Photo to see the image in greater detail.https://cupola.gettysburg.edu/hiddenpapers/1005/thumbnail.jp

Faulty Successive Cancellation Decoding of Polar Codes for the Binary Erasure Channel

We study faulty successive cancellation decoding of polar codes for the binary erasure channel. To this end, we introduce a simple erasure-based fault model and we show that, under this model, polarization does not happen, meaning that fully reliable communication is not possible at any rate. Moreover, we provide numerical results for the frame erasure rate and bit erasure rate and we study an unequal error protection scheme that can significantly improve the performance of the faulty successive cancellation decoder with negligible overhead.Comment: As presented at ISITA 201

MIMO Transmission with Residual Transmit-RF Impairments

Physical transceiver implementations for multiple-input multiple-output (MIMO) wireless communication systems suffer from transmit-RF (Tx-RF) impairments. In this paper, we study the effect on channel capacity and error-rate performance of residual Tx-RF impairments that defy proper compensation. In particular, we demonstrate that such residual distortions severely degrade the performance of (near-)optimum MIMO detection algorithms. To mitigate this performance loss, we propose an efficient algorithm, which is based on an i.i.d. Gaussian model for the distortion caused by these impairments. In order to validate this model, we provide measurement results based on a 4-stream Tx-RF chain implementation for MIMO orthogonal frequency-division multiplexing (OFDM).Comment: to be presented at the International ITG Workshop on Smart Antennas - WSA 201

Comparison of Polar Decoders with Existing Low-Density Parity-Check and Turbo Decoders

Polar codes are a recently proposed family of provably capacity-achieving error-correction codes that received a lot of attention. While their theoretical properties render them interesting, their practicality compared to other types of codes has not been thoroughly studied. Towards this end, in this paper, we perform a comparison of polar decoders against LDPC and Turbo decoders that are used in existing communications standards. More specifically, we compare both the error-correction performance and the hardware efficiency of the corresponding hardware implementations. This comparison enables us to identify applications where polar codes are superior to existing error-correction coding solutions as well as to determine the most promising research direction in terms of the hardware implementation of polar decoders.Comment: Fixes small mistakes from the paper to appear in the proceedings of IEEE WCNC 2017. Results were presented in the "Polar Coding in Wireless Communications: Theory and Implementation" Worksho

Contact-allergy time

The most commonly used techniques for the in vivo evaluation of the cellular immune response include intracutaneous testing with microbial recall antigens or sensitization with neoantigens. The reliability of these tests for the individual patient usually is low due to the lack of standardization and quantification. Moreover only the efferent branch of the immune response can be judged. The dinitrochlorobenzene-contact allergy time (DNCB-CAT) is a quantitative approach for the assessment of the cellular immune response. 2% DNCBointment is applied on the upper arm in a 1 cm2 area. On the following days patch-testing with 0.05% DNCB-ointment is done on the homolateral forearm in alternating localizations till an allergic contact dermatitis reaction appears. As assessed in patients with malignant melanoma (MM, n=\\5) and with lymphoproliferative disorders (LD, η = 25), the DNCB-CAT correlates with the age of the patients and can be expressed by a formula given by the age (years) χ factor (MM = 0.16; LD = 0.17) + constant figure (MM = 5.5; LD = 4.3). There was no significant difference between the two groups or subgroups investigated. By DNCB-CAT quantitative analysis of the cellular immune response in vivo is possible. It is an appropriate model for further investigations of the cellular immunity under different clinical, histological, prognostic, and therapeutic aspects

The Role of Dialect Words in Children’s Social Decisions

Recent research suggests that young children are capable of distinguishing between phonetically dissimilar spoken accents, yet have difficulty distinguishing between phonetically similar accents (Wagner, Clopper, & Pate, 2013). The present study aimed to determine whether the presence of dialect-specific vocabulary enhances young children’s ability to categorize speakers. Participants completed four training trials in which they were familiarized with photos of two children: one of whom used American English labels for test objects and one of whom used British English labels. After training trials, participants completed eight test trials in which they were asked to infer which target child would use either British or American English labels to describe novel test objects. After all test trials were completed, participants were asked to select which target child they would prefer to ask for the name of an unfamiliar object. Participants were also asked to select which target child they would rather play a game with. Participants of all ages were significantly able to correctly categorize speakers based on whether they used dialect specific vocabulary that was familiar or unfamiliar to the participant. Participants showed a significant preference for the target child who used American dialect words. Participants also significantly trusted the American English-speaking target child over the British English-speaking target child to have the correct name for the unknown object. Neither categorization success, preference, nor selective trust differed significantly by age. These interesting results suggest that, when accent differences are too subtle for children to categorize speakers, dialect-specific vocabulary may enhance young children’s ability to categorize a speaker. The results of the preference and selective trust questions suggest that children as young as four years use their knowledge of a speaker’s vocabulary to guide their preferred social interactions, choosing to interact with others who speak similarly to them

Feedback-Aware Precoding for Millimeter Wave Massive MIMO Systems

Millimeter wave (mmWave) communication is a promising solution for coping with the ever-increasing mobile data traffic because of its large bandwidth. To enable a sufficient link margin, a large antenna array employing directional beamforming, which is enabled by the availability of channel state information at the transmitter (CSIT), is required. However, CSIT acquisition for mmWave channels introduces a huge feedback overhead due to the typically large number of transmit and receive antennas. Leveraging properties of mmWave channels, this paper proposes a precoding strategy which enables a flexible adjustment of the feedback overhead. In particular, the optimal unconstrained precoder is approximated by selecting a variable number of elements from a basis that is constructed as a function of the transmitter array response, where the number of selected basis elements can be chosen according to the feedback constraint. Simulation results show that the proposed precoding scheme can provide a near-optimal solution if a higher feedback overhead can be afforded. For a low overhead, it can still provide a good approximation of the optimal precoder.Comment: 7 pages, 5 figures, to appear at the IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC) 201