Optimal overlayer inspired by Photuris firefly improves light-extraction efficiency of existing light-emitting diodes

In this paper the design, fabrication and characterization of a bioinspired overlayer deposited on a GaN LED is described. The purpose of this overlayer is to improve light extraction into air from the diode's high refractive-index active material. The layer design is inspired by the microstructure found in the firefly Photuris sp. The actual dimensions and material composition have been optimized to take into account the high refractive index of the GaN diode stack. This two-dimensional pattern contrasts other designs by its unusual profile, its larger dimensions and the fact that it can be tailored to an existing diode design rather than requiring a complete redesign of the diode geometry. The gain of light extraction reaches values up to 55% with respect to the reference unprocessed LED.Comment: 9 pages, 9 Figures, published in Optics Expres

An analysis of lexical collocation errors in students’ writing

Mastering lexical collocation uses in learning English as a foreign language is absolutely essential to develop students’ communicative skills and linguistic abilities. Most students, however, have problems with putting words together in a characteristic of “natural” English native speaker-like manner during writing. Students tend to use strange lexical collocation expressions therefore students’ language production does not sound natural and carries imprecise meaning. With regard to this underlying issue, the main emphasis of the current study was lying on the investigation of the types and the causes of lexical collocation error committed by EFL students in their argumentative writing. Through a qualitative research approach applying a descriptive-analytic method, sixteen university students were chosen purposively. The data were collected from two principal sources i.e., students’ writing samples and semi-structured interviews. In terms of data analysis technique, this study employed an error analysis technique developed by Ellis (1994) to analyze the obtained lexical collocation errors and applied a content analysis technique provided by Kumar (2011) to analyze the interview results. The study revealed 54 erroneousness of lexical collocation production consisting of verb + noun/pronoun (PP), adjective + noun, adverb + adjective, noun + noun, and verb + adverb combination. These errors were caused by a lack of collocation competence, native language influence, the use of synonym, overgeneralization, and approximation

Evaluation of the teaching and learning in listening subject

This present study is conducted to evaluate the teaching of listening skills in the English Department at Gorontalo State University. Evaluation in this study is to benchmark the current practice of teaching listening in the English Department of State University of Gorontaloto the research-based practice. Research finding suggests that the teaching of listening to the English Department students partly has followed methodologies proposed by Richards and Goh (2008). This study shows that in general the practice of the teaching of listening at the English Department of State University of Gorontalo is based on research-based methodologies. However, there are some points that need to be improved. Since the result of the study has addressed only some of the issues in the teaching of listening, therefore, future research on other issues of listening teaching needs to be done

Combining Haar Wavelet and Karhunen Loeve Transforms for Medical Images Watermarking

International audienceThis paper presents a novel watermarking method, applied to the medical imaging domain, used to embed the patient's data into the corresponding image or set of images used for the diagnosis. The main objective behind the proposed technique is to perform the watermarking of the medical images in such a way that the three main attributes of the hidden information (i.e. imperceptibility, robustness, and integration rate) can be jointly ameliorated as much as possible. These attributes determine the effectiveness of the watermark, resistance to external attacks and increase the integration rate. In order to improve the robustness, a combination of the characteristics of Discrete Wavelet and Karhunen Loeve Transforms is proposed. The Karhunen Loeve Transform is applied on the sub-blocks (sized 8x8) of the different wavelet coefficients (in the HL2, LH2 and HH2 subbands). In this manner, the watermark will be adapted according to the energy values of each of the Karhunen Loeve components, with the aim of ensuring a better watermark extraction under various types of attacks. For the correct identification of inserted data, the use of an Errors Correcting Code (ECC) mechanism is required for the check and, if possible, the correction of errors introduced into the inserted data. Concerning the enhancement of the imperceptibility factor, the main goal is to determine the optimal value of the visibility factor, which depends on several parameters of the DWT and the KLT transforms. As a first step, a Fuzzy Inference System (FIS) has been set up and then applied to determine an initial visibility factor value. Several features extracted from the Co-Occurrence matrix are used as an input to the FIS and used to determine an initial visibility factor for each block; these values are subsequently re-weighted in function of the eigenvalues extracted from each sub-block. Regarding the integration rate, the previous works insert one bit per coefficient. In our proposal, the integration of the data to be hidden is 3 bits per coefficient so that we increase the integration rate by a factor of magnitude 3

STRATEGI KEGIATAN LITERASI DENGAN TEMA "FUN LEARNING" UNTUK MENINGKATKAN KEMAMPUAN MEMBACA BAHASA INGGRIS PADA ANAK

  Abstrak Membaca adalah kebiasaan yang dapat di pupuk dan dikembangkan pada anak. Secara umum memotivasi anak untuk membaca adalah tugas yang sulit, apalagi membaca teks dalam Bahasa Inggris. Oleh karena itu, tujuan dari pengabdian pada masyarakat ini adalah meningkatkan kemampuan anak usia sekolah dasar belajar bahasa Inggris khususnya pada pembelajaran membaca (reading skill) yang salah satu caranya dengan menggunakan teknik Fun Learning yaitu belajar dengan kegiatan yang menyenangkan. Inovasi yang di gunakan pada kegiatan ini adalah menggabungkan ciri belajar cerdas, mudah, cepat dan menyenangkan. Pengabdian ini dilaksanakan sebanyak 4 kali pertemuan. Metode pelaksanaan kegiatan berupa model pembelajaran langsung, pemberian tugas, dan demonstrasi. Dengan pelaksanaan pengabdian ini diharapkan dapat memotivasi para siswa agar lebih menyukai belajar Bahasa Inggris, sehingga kedepan mereka lebih bersiap untuk terus belajar bahasa inggris. Oleh sebab itu, media dan strategi penyampaian materi ajar bahasa Inggris harus benar-benar dilakukan dengan cermat dan matang, terutama materi yang akan diberikan kepada siswa level beginner. Dengan demikian literasi Bahasa inggris mereka meningkat sehingga tercapai masyarakat yang berwawasan internasional. Kata kunci: Membaca; Strategi; Media; Fun Learning; Pembelajaran Langsung; Demonstrasi.

Pembelajaran Menyenangkan sebagai Upaya Memberdayakan Potensi dan Menumbuhkan Minat Belajar Siswa SDIT Quratu A’yun Kota Gorontalo

The purpose of this community service activity is to empower students’ potential in English through fun learning activities, as well as to foster students’ interest in learning English. This activity is conducted by implementing several games and songs in learning processes. The 5th grade students of SDIT Qurratu A’yun, which was located in Kota Tengah Districst, Gorontalo City, with a total number of 20 students were taken as the sample of this activity. This community service activity was carried out for eight meetings using various methods and materials that were considered fun for the students. The result showed that the students were interested and motivated in learning English that led to their vocabulary improvement

Improved data visualisation through multiple dissimilarity modelling

Popular dimension reduction and visualisation algorithms rely on the assumption that input dissimilarities are typically Euclidean, for instance Metric Multidimensional Scaling, t-distributed Stochastic Neighbour Embedding and the Gaussian Process Latent Variable Model. It is well known that this assumption does not hold for most datasets and often high-dimensional data sits upon a manifold of unknown global geometry. We present a method for improving the manifold charting process, coupled with Elastic MDS, such that we no longer assume that the manifold is Euclidean, or of any particular structure. We draw on the benefits of different dissimilarity measures allowing for the relative responsibilities, under a linear combination, to drive the visualisation process