Low bend loss femtosecond laser written waveguides exploiting integrated microcrack

We introduce the fabrication and use of microcracks embedded in glass as an optical element for manipulating light propagation, in particular for enhancing waveguide performance in silica integrated optics. By using a femtosecond laser to induce a strong asymmetric stress pattern in silica, uniform cracks with set dimensions can be created within the substrate and propagated along a fixed path. The smoothness of the resulting cleave interface and large index contrast can be exploited to enhance waveguide modal confinement. As a demonstration, we tackle the longstanding high bend-loss issue in femtosecond laser written silica waveguides by using this technique to cleave the outer edge of laser written waveguide bends, to suppress radiative bend loss. The microcrack cross section is estimated to be 15 μm in height and 30 nm in width, for the 10 $$\times$$ × 10 μm waveguides. At 1550 nm wavelength, losses down to 1 dB/cm at 10 mm bend radius were achieved, without introducing additional scattering. Both the cleave stress pattern and waveguide are fabricated with the same multiscan writing procedure, without requiring additional steps, and re-characterisation of the waveguides after 1 year confirm excellent long term performance stability.

Spectrally-selective Time-resolved Emission through Fourier-filtering (STEF)

In this manuscript we demonstrate that directing the emitted photon stream from a fluorescent sample through a fixed path-length imbalanced Mach-Zehnder interferometer allows us to separate and resolve the dynamics of different emitters without the use of filtering optics. Our method, Spectrallyselective Time-resolved Emission through Fourier-filtering (STEF) takes advantage of a careful selection of interferometer position where one signal can be canceled (or enhanced) due to its unique spectral characteristics. STEF is straightforward to implement and provides a complementary approach to separate spectrally overlapped signals based on their coherence length and carrier frequency. We also discuss how one can implement STEF with an imperfect Mach-Zehnder interferometer, increasing the utility of this method, and demonstrate how Mach-Zehnder filtering can be used to image fluorophores in biologically relevant samples.

Comprehensive Analysis of Electric Field Characteristics for Multi-Winding Medium Frequency Transformer

The multi-winding medium frequency transformer (MMFT) has attracted widespread attention, since its application in power electronic transformers can simplify the system structure and reduce the volume and weight. However, the special working conditions of MMFT due to high voltage and high power density increase the difficulty of insulation design for MMFT. For this issue, this paper presents a comprehensive analysis of electric filed characteristics for MMFT. First, the electric field model of MMFT is established using the 2-D finite element method. Based on it, the influences of connection mode, core structure, and hollow winding on the electric field characteristics of MMFT are studied, including the overall electric field distribution, maximum electric field intensity, and the electric field intensity along a fixed path. The results show that there are differences in the maximum electric field intensity for different connection modes and different core structures, which provides references for MMFT insulation design. The proposed modeling method and analysis results in this paper are important for insulation improvement of MMFT.

Plant Layout dan penentuan Critical Control Point Pada proses produksi Ikan Cakalang (Katsumonus pelamis) di PT. Samudra Sakti Sepakat Laha-Ambon“

Peranan perikanan dalam pembangunan ekonomi cukup besar, baik sebagai penghasil bahan pangan sumber protein maupun sebagai penghasil devisa negara. Salah satu daerah di Indonesia yang memiliki potensi sumberdaya kelautan dan perikanan yang besar adalah Provinsi Maluku. Maluku adalah provinsi kepulauan dengan luas wilayah 712.479,69 km², terdiri dari 92,4 % luas perairan laut atau sebesar 658.294,69 km² dibandingkan luas daratan yang hanya 7,6 % (54.185 km²). Kondisi perairan tersebut diperkaya oleh potensi sumberdaya perikanan sebanyak 1.640.160 ton/tahun. Potensi sumberdaya hayati perikanan dimaksud terdiri dari pelagis, demersal, dan biota laut lainnya yang dapat dimanfaatkan secara optimal. (Dinas Perikanan dan Kelautan Provinsi Maluku,2007). HACCP (Hazard Analysis Critical Control Point) adalah suatu sistem kontrol dalam upaya pencegahan terjadinya masalah yang didasarkan atas identifikasi titik-titik kritis di dalam tahap penanganan dan proses produksi. HACCP merupakan salah satu bentuk manajemen resiko yang dikembangkan untuk menjamin keamanan pangan dengan pendekatan pencegahan (preventive) yang dianggap dapat memberikan jaminan dalam menghasilkan makanan yang aman bagi konsumen. Penelitian ini bersifat deskriptif yaitu mengadakan deskripsi untuk memberikan gambaran yang jelas tentang kondisi nyata subyek penelitian. dan Metode yang digunakan dalam Penelitian ini adalah, Analisis deskriptif kualitatif, yakni Melihat Layout Pabrik dan menghitung tingkat kesediaan produk jadi, Menganalisis Alur Produksi untuk Melihat CCP (titik titik critis), Metode observasi yakni pengamatan langsung di lapangan, degan pengambilan sample adalah Purposive sampling. Hasil identifikasi titik kritis (CCP) berdasarkan hasil Pengamatan dan Penentuan CCP Mengunakan Metode decision tree diketahui bahwa tahap pembekuan ,dan Penyimpanan, dinyatakan sebagai titik kritis (CCP). Dalam pemantauan/monitoring CCP Pada PT. Samudara Sakti Sepakat telah menerapkan prosedur, pengendalian titik titik kritis dengan ciri-ciri khusus dan penanganan tersendiri. Faktor utama yang menjadi pertimbangan dalam penentuan lokasi pabrik (plant location) adalah lokasi bahan baku, lokasi pasar, tenaga kerja dan tingkat upah serta air dan limbah industri yang dibuang. Jenis tata letak pabrik (plant layout) yang terdapat pada perusahaan tersebut merupakan produk layout yakni berdasarkan aliran produksi, dikarenakan berbagai faktor, seperti jenis produk yang dibuat hanya satu macam (ikan utuh), diproduksi dalam jumlah besar dan untuk jangka waktu yang relatif singkat, jenis mesin yang digunakan ditujukan untuk komponen yang serupa, serta jenis mesin bersifat special purpose machine, yakni hanya ditujukan untuk fungsi tertentu saja. Mesin-mesin yang digunakan khususnya untuk memproduksi ikan beku bersifat fixed path machine, dan proses produksi bersifat continue process (terjadi terus menerusKata Kunci: Penentuan HACCP

Evidences in resemblance of archaeological structures of Kesariya and Borobudur Stupa

India’s cultural interface with southeast Asia started around the beginning of Christian era with the discovery of monsoon which traverses a fixed path or direction with remarkably predictable timing or annual cycle thereby generating confidence of safe and convenient maritime trade from the west as well as east Indian coast. This article is aimed to seek the connections and relation between India and Indonesia through deep observations and comparison to the Kesariya (India) and Borobudur (Indonesia). Using Ethnology approaches some evidences has been found

Creativity for Sustainability: How Do Polish Teachers Develop Students’ Creativity Competence? Analysis of Research Results

Called the competence of the 21st century, creativity is one of the key competencies for sustainable development. There is no fixed path to achieve sustainability and it is subject to human creativity. However, integrated development of both is surely an under-researched topic. Creative thinking and creative problem solving should be a necessary and significant component of modern sustainable education. Students must learn to associate creativity with sustainability. Helping them understand sustainability by exposing them to the sustainable development goals (SDGs) and designing new creations that honor the planetary boundaries is crucial. The paper focuses on developing creativity by Polish teachers who work with adolescents. The assumption was that creativity can be developed using certain didactic methods and forms. The objective of the study was to explore and to describe which didactic methods and forms teachers use to shape the competence of creativity in students. The teachers took part in a survey and were asked what methods and forms they use to develop creativity in their students. The sample consisted of 337 teachers from the Małopolska region. The results of the analyses show that teachers use only a few of the methods recommended to facilitate creativity, which may lead to a low level of this competence among the students. They also use the most common didactic forms, which may not support the development of creativity competences. Moreover, the research results show that there are several factors, such as the teacher’s seniority and the location of the school, which determine the choice of individual teaching methods.

GAFOR: Genetic Algorithm Based Fuzzy Optimized Re-Clustering in Wireless Sensor Networks

In recent years, the deployment of wireless sensor networks has become an imperative requisite for revolutionary areas such as environment monitoring and smart cities. The en-route filtering schemes primarily focus on energy saving by filtering false report injection attacks while network lifetime is usually ignored. These schemes also suffer from fixed path routing and fixed response to these attacks. Furthermore, the hot-spot is considered as one of the most crucial challenges in extending network lifetime. In this paper, we have proposed a genetic algorithm based fuzzy optimized re-clustering scheme to overcome the said limitations and thereby minimize the effect of the hot-spot problem. The fuzzy logic is applied to capture the underlying network conditions. In re-clustering, an important question is when to perform next clustering. To determine the time instant of the next re-clustering (i.e., number of nodes depleted—energy drained to zero), associated fuzzy membership functions are optimized using genetic algorithm. Simulation experiments validate the proposed scheme. It shows network lifetime extension of up to 3.64 fold while preserving detection capacity and energy-efficiency.

Opportunistic and On-Demand Network Coding-Based Solutions for LPWAN Forwarding

The single-hop star-of-stars topology in low-power and wide-area networks (LPWAN) exhibits reliability and substandard coverage issues, especially in urban areas where line-of-sight (LoS) communication is difficult to achieve. Moreover, LPWAN trade-off the data rate to achieve longer coverage, preventing other end-devices from using the time resource. Locating other gateways is uneconomical as it requires infrastructure, such as the internet and a power connection. In this study, we propose a forwarding scheme with a relay to increase LPWAN coverage and reliability while not degrading the network’s capacity. A relay tends to incur unnecessary forwarding that degrades the network capacity unless proper countermeasure is prepared. Our works, namely opportunistic and on-demand network coding (OODC), minimize unnecessary forwarding and make good use of multiple-receiving relays. Network coding is also applied in the relay for better transmission efficiency and reliability simultaneously. Because network coding occurs header overhead, we perform a header compression technique to counter it. According to our simulation result, our method shows better reliability than fixed path forwarding. In an adaptive data rate settings, the OODC achieves a 92% packet delivery ratio (PDR), whereas a fixed-path forwarding only achieves an 84% PDR.

Fuzzy-based Adaptive Multipath for En-route Filtering in Dynamic Wireless Sensor Network

Wireless sensor network is formed with limited energy resources, easily compromised by an adversary because of hostile environments. Adversary may use compromised nodes to inject false reports and launch DoS attacks, thus, sensor nodes are prone to failure and which makes the network topology configurations highly dynamic in real world applications. A variety of en-route filtering schemes have been proposed to drop and defeat these attacks by using their own cryptographic methods. Some of them ask for a fixed path between a base station and each cluster, so they are not feasible for dynamic network. Additionally, other proposals do not consider various environmental variables in a dynamic environment, so they only choose static paths. In contrast, we consider topology changes, communication costs, the maximum number of key dissemination hops, and the spread of nodes for providing optimum filtering capacity. This paper presents a fuzzy-based adaptive multipath selection method in dynamic environment of a wireless sensor network. Our proposed method can adjust the optimized number of multipaths during key dissemination. Experimental results show that relatively higher filtering capacity with lower energy consumption and suitable nodes for highly dynamic networks.