Achievable Information Rates for Coded Modulation with Hard Decision Decoding for Coherent Fiber-Optic Systems

We analyze the achievable information rates (AIRs) for coded modulation schemes with QAM constellations with both bit-wise and symbol-wise decoders, corresponding to the case where a binary code is used in combination with a higher-order modulation using the bit-interleaved coded modulation (BICM) paradigm and to the case where a nonbinary code over a field matched to the constellation size is used, respectively. In particular, we consider hard decision decoding, which is the preferable option for fiber-optic communication systems where decoding complexity is a concern. Recently, Liga \emph{et al.} analyzed the AIRs for bit-wise and symbol-wise decoders considering what the authors called \emph{hard decision decoder} which, however, exploits \emph{soft information} of the transition probabilities of discrete-input discrete-output channel resulting from the hard detection. As such, the complexity of the decoder is essentially the same as the complexity of a soft decision decoder. In this paper, we analyze instead the AIRs for the standard hard decision decoder, commonly used in practice, where the decoding is based on the Hamming distance metric. We show that if standard hard decision decoding is used, bit-wise decoders yield significantly higher AIRs than symbol-wise decoders. As a result, contrary to the conclusion by Liga \emph{et al.}, binary decoders together with the BICM paradigm are preferable for spectrally-efficient fiber-optic systems. We also design binary and nonbinary staircase codes and show that, in agreement with the AIRs, binary codes yield better performance.Comment: Published in IEEE/OSA Journal of Lightwave Technology, 201

Multi-microelectrode devices for intrafascicular use in peripheral nerve

This minisymposium paper gives an overview of experimental, modeling, design and microfabrication steps which lead towards the University of Twente three-dimensional 128-fold silicon microelectrode device. The device is meant for implantation in peripheral nerve for neuromuscular control purposes and is estimated to be able to selectively control 10-20 motor fibres. Also, the potentialities of an alternative LIGA microfabrication technology are considered. A brief comparison is made with the two-dimensional sieve and flexible foil types of neuro electronic interfaces, under development elsewhere. Microfabrication technologies appear to be an important tool, but evidence is accumulating that for selective neuroelectronic interfacing the micro devices are not yet small/selective enough. More precision and selectivity is needed to contact individual axons intimately and selectively. Therefore, new lines of research develop towards in-vitro-neuron-cultured MEPs (Multi Electrode Plates) to be implanted in neural tissu

A new approach to evaluate fracture strength of UV-LIGA fabricated nickel specimens

One of the major difficulties faced by MEMS researchers today is the lack of data regarding properties of electroplated metals or alloys at micro-levels as those produced by the LIGA and LIGA related process. These mechanical properties are not well known and they cannot be extrapolated from macro-scale data without experimental verification. This lack of technical information about microscale physical properties has affected the consistency and reliability of batch-fabricated components and leads to very low rates of successful fabrication. Therefore, this material issue is of vital importance to the development of LIGA technology and to its industrial applications. This thesis focuses on the development of a new capability based on design, fabrication, and testing of groups of UV-LIGA fabricated nickel microspecimens for the evaluation of fracture strength. The design of the test specimens involved determining the appropriate dimensions and configuration based on a set of criteria dictated by the objectives of the project. Likewise, the development of the specimens required some experimentation with different microfabrication techniques, and combinations thereof, to generate a final fabrication sequence that would produce suitable freestanding, wafer-bound specimens. The devised testing mechanism demonstrated compatibility with the fabricated samples and capability of performing the desired experimentation by generating resistance-to-fracture values of the nickel specimens. The average fracture strength value obtained, expressed with a 95% confidence interval, was 315 ± 54 MPa. Preliminary testing results proved that further data acquisition, especially involving tensile specimen testing, and material analysis is needed to fully understand the implications of the information obtained. The products of this new microspecimen testing approach can be extended for use with other microfabricated metals and metal alloys, particularly on a more qualitative, comparative basis

Design and fabrication of a LIGA milliengine

This paper reports on the design and fabrication of a new milliscale magnetic actuator that is ideally suited for LIGA processing. LIGA processing permits the fabrication of millisized machine elements that cannot be fabricated by conventional miniature machining techniques because of their small feature sizes. The Milliengine is a magnetically driven device that utilizes a unique design to extend the 2-dimensional fabrication capability of LIGA to create 3-dimensional machinery

Design and fabrication of electromagnetic micro-relays using the UV-LIGA technique

This dissertation reports a research effort to microfabricate an electromagnetic relay for power applications using a multilayer UV-LIGA process. A mechanically wrapped coil was used and very simple design for the magnetic circuit was adopted to increase the design flexibility and performances. The broad material selection and the capability of making high aspect ratio microstructures of the UV-LIGA make the technology best suited for fabricating microelectromechanical power relays. Fabrication of the device required significant advances in the optical lithography of SU-8 negative photoresist. Research proved that aspect-ratios up to 40:1 in isolated open field structures of thickness between 1 and 1.5 mm can be obtained a standard broadband UV source. The principal factor in this achievement is the reduction of internal stress during the post-exposure bake process that eliminates large plastic deformations present during standard bake procedures. Another challenging issue associated with producing high aspect ratio microstructures is the development narrow groves and deep holes in SU-8 lithography. To overcome this obstacle, megasonic agitation was applied to the developer bath, which resulted in faster development rates, more uniform development, and the ability to produce structures with higher aspect ratios. To date, this process has been used to achieve 100:1 aspect ratio open field features and 45:1 intact cylinder arrays. A multi-layer SU-8 optical lithography and metal electrodeposition process was developed to fabricate the relay. The design required implementation of high aspect ratio lithographic processing techniques to produce a tall nickel magnetic core and insulated magnetic cup in which a pre-wrapped solenoid would be placed for electromagnetic driving. After insertion of the solenoid a Ni-Fe actuator was bonded to the relay base to complete the device. To better understand the fatigue life of electroplated microstructures, a theoretical model was developed determine the possible fracture mechanics properties and fatigue life of LIGA fabricated nickel and nickel-iron alloys for use in microsystems applications. The prototype micro-relays were tested for the dynamic characteristics and power capacity. The experimental results have confirmed that reasonably large current capacity and fast response speed can be achieved using electromagnetic actuation and the multi-layer UV-LIGA fabrication process developed

Pengaruh Latihan Double Leg Cone Hop Dan Knee Tuck Jump Terhadap Peningkatan Kemampuan Tendangan Jarak Jauh Dalam Permainan Sepakbola di SSB Bina Liga U-15 Kota Pemalang

Penelitian ini dilatarbelakangi oleh kurang maksimalnya tendangan jarak jauh yang dihasilkan para pemain SSB Bina Liga U-15 Pemalang, yang disebabkan karena saat latihan pelatih lebih fokus dalam melatih taktik dan daya tahan tubuh tanpa memberikan latihan untuk meningkatkan kemampuan khusus salah satunya tendangan jarak jauh. Tujuan penelitian ini adalah untuk mempelajari pengaruh dari latihan double leg cone hop dan knee tuck jump terhadap peningkatan kemampuan tendangan jarak jauh pada permainan sepakbola di SSB Bina Liga U-15 Kota Pemalang. Metode yang digunakan dalam penelitian ini adalah metode kuantitatif eksperimen dengan desain Two Group Pretest-Posttest Design. Populasi dalam penelitian ini adalah seluruh pemain SSB Bina Liga Kota Pemalang yang berjumlah 78 pemain yang terdiri dari berbagai kelompok usia, sedangkan sampel yang digunakan dalam penelitian ini adalah pemain SSB Bina Liga U-15 Kota Pemalang yang berjumlah 16 pemain, teknik sampling yang digunakan adalah purposive sampling. Instrumen penelitian yang digunakan dalam tes ini adalah instrumen tes kemampuan tendangan jauh dengan validitas 0,978 dan relibilitas sebesar 0,989 di ambil dari Barrow (dalam Setyawan, 2019). Hasil penelitian menunjukan perhitungan uji t untuk latihan double leg cone hop diperoleh Thitung > Ttabel  yaitu 5,642 > 1,895 maka Ho ditolak dan Ha diterima. Sedangkan untuk latihan knee tuck jump diperoleh Thitung > Ttabel  yaitu 5,691 > 1,895 maka Ho ditolak dan Ha diterima.  Dari perhitungan tersebut bisa disimpulkan bahwa latihan knee tuck jump lebih baik daripada latihan double leg cone hop terhadap peningkatan tendangan jarak jauh di SSB Bina Liga U-15 Kota Pemalang. Hal ini dikarenakan latihan knee tuck jump dengan cara melompat ke atas diam ditempat itu menyebabkan otot-otot dan sendi yang terkena jauh lebih terpusat dan lebih terfokus serta tekanan saat melakukan tidak berkuran

Microsystems technology: objectives

This contribution focuses on the objectives of microsystems technology (MST). The reason for this is two fold. First of all, it should explain what MST actually is. This question is often posed and a simple answer is lacking, as a consequence of the diversity of subjects that are perceived as MST. The second reason is that a map of the somewhat chaotic field of MST is needed to identify sub-territories, for which standardization in terms of system modules an interconnections is feasible. To define the objectives a pragmatic approach has been followed. From the literature a selection of topics has been chosen and collected that are perceived as belonging to the field of MST by a large community of workers in the field (more than 250 references). In this way an overview has been created with `applications¿ and `generic issues¿ as the main characteristics

Morphology of the transverse ligament of the atlas and the alar ligaments in the silver fox (Vulpes vulpes var)

Background Recent new anatomical and histological features of craniocervical junction in dogs and cats were described providing evidence of differences between the carnivore species. No information on these structures in foxes exists. Results Two parts of the alar ligaments were found. A longer one aroused from dens of axis to the internal (medial) surface of the occipital condyles and was called apical part. A shorter part originated from the entire length of the lateral edge of the dens of axis and terminated on the internal wall of the vertebral foramen of atlas and thus was called the lateral part. The transverse ligament of the atlas was widened in the mid region, above the dens of axis, and thickened at enthesis. Periosteal fibrocartilage was detected in the transverse ligament of the atlas at the enthesis, and sesamoid fibrocartilage was present on periphery in the middle of the ligament. Conclusions The craniocervical junction in foxes differs in part from other carnivores such as dogs and cats but resembles that of mesaticephalic dogs. The sesamoid and periosteal fibrocartilage supports the transverse ligament of the atlas whereas the alar ligaments have no cartilage