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We formulate and analyze a fully-discrete approximate solution of the linear Schrödinger equation on the unit square written as a Schrödinger-type system. The finite element Galerkin method is used for the spatial discretization, and the time-stepping is done with an alternating direction implicit extrapolated Crank-Nicolson method. We demonstrate the existence and uniqueness of the approximation, and prove that the scheme is of optimal accuracy in the L2 , H1 and L∞ norms in space and second–order accurate in time. Numerical results are presented which support the theory.

The result of the current technological developments makes increasingly tight telecommunication provider competition. Various opinions expressed by customers about telecommunication providers are found in social media. Twitter is widely used by the public to share information and socialize; also, to share opinions, express opinions of a product or service, and provide reviews on communication providers. Many reviews are provided by users on Twitter, making it hard to classify manually. Therefore, to make it easy to classify the tweets, an automation system is needed to determine that a comment is positive or negative. Maximum Entropy can be used for sentiment analysis of Indosat Ooredoo tweets. On these grounds, this study explains how to define tweets into positive and negative classes with applications created using Java. Based on the research and after testing, the Maximum Entropy obtained an accuracy value of 86.21% and an AUC value of 0.968.

Pada saat ini, WiFi sudah banyak dipasang tidak hanya di lingkungan perkantoran atau pusat perbelanjaan, tetapi juga di perumahan-perumahan sudah banyak terpasang jaringan WiFi. Semakin maraknya minat menggunakan WiFi, semakin banyak pula orang yang tertarik untuk mencari celah keamanan. Hanya dengan memberikan password pada jaringan WiFi, bukan berarti WiFi yang sudah terpasang benar-benar aman. Pada penelitian ini, peneliti melakukan analisis rekayasa sosial dengan menggunakan dua metode, yaitu WiFi deauther dan evil twin untuk menguji kerentanan keamanan WiFi. Deauther bekerja dengan cara memutus jaringan komunikasi elektronik. Sedangkan evil twin adalah penyerangan jaringan dengan meniru teknik access point yang asli. Tujuan dari penelitian ini adalah agar masyarakat lebih memahami bahaya rekayasa sosial dan mampu mengantisipasinya. Dari pengujian yang telah dilakukan, didapatkan hasil bahwa kedua cara yang digunakan terbukti dapat meretas jaringan WiFi yang dituju.

Heat dissipation in space applications is very much necessary. For example, a satellite works under an extreme temperature environment depending on the satellite’s position in the orbit. Apart from thermal energy from the sun, the electronic component in the satellite itself generates heat as well. To maintain the temperature of the components within their operational range, a grooved heat pipe (GHP) is one of the best solutions. Within GHP, capillary action plays a major role to transfer the liquid from the condenser side to the evaporator side under a near-zero gravitational environment. This paper focuses on the numerical simulation of heat and mass transfer in GHP for space application. The Computational Fluid Dynamics (CFD) simulation is performed using Ansys Fluent software. The omega-shaped axial micro-channelled GHP made from aluminium is considered for this study. The working fluid in the heat pipe is ammonia. The volume-of-fluid (VOF) multiphase model along with the Lee model equation is used to perform the mass transfer prediction. The effects of different heat load for a 25% filling ratio (FR) are studied. This paper mainly focuses on the fluid flow development in the initial 40s of the GHP operation for a specified percentage of FR and heat load. The CFD simulations give much more insights of the heat and mass transfer phenomena, which would not possible to obtain by experimentation. The results like pressure, velocity, temperature, and volume fraction profiles inside the GHP along the length were studied.

The development of the use of advanced technology in the form of computerized applications has become a trend and is widely used in all fields. One of the fields that take advantage of the use of automated technology is the library. However, not all of these applications can run well by the application creation hypothesis. For this reason, application testing is required before implementation to avoid bugs or errors. Consider the application testing phase importance, testing with the black box method was carried out on library applications using the Boundary Value Analysis (BVA) technique in this study. These testing methods and techniques were chosen. When the application is implemented, there will be no more errors caused by differences in the value data during the input process with the stored value data, after testing using the black box method with the BVA technique and documentation of each test. All the library application functions have been running according to the initial application plan made, and there are no more bugs or errors when the application is run.

The impact of indoor environmental quality on human health and wellbeing has been widely documented, as has its impact on worker productivity in settings such as education, healthcare, and manufacturing. In the knowledge worker context, however, there is limited consensus on agreed metrics for productivity measurement, leading to a paucity of research regarding the impact of specific realworkplace interventions on worker performance. This paper presents an organizational benchmarking and evaluation tool to permit such tracking within an organization. Based on the results of a systematic literature review, five dimensions are used to evaluate productivity in this context: absenteeism, presenteeism, engagement, self-assessed (individual) productivity, and objective (office-wide) productivity. This data is collected from organizational reports, individual employee questionnaires, and field data. The resultant tool was refined through a series of public- and private-sector field tests and the evaluation of results was undertaken through post-analysis interviews with organizational partners who provided feedback on the clarity of data as-presented, alignment with known issues, and consistency with other studies. The evaluated tool provides a holistic means of assessing knowledge worker productivity and will support future research to evaluate and quantify the impact of specific interventions in workplace policy and environmental modifications.

In today’s world global real estate investments have taken over more than twice the size of the stock market. Even after the dominance of the real estate market there are still a less number of investors due to liquidity and global access to sensitive or critical information. Due to various flaws in security in the current system, the tenants and owners are barely satisfied. The main focus of this paper is to incorporate the use of blockchain in the current real estate market and represent the facilities and advantages it can give to the real estate market. Blockchain based real estate is better because each block contains a cryptic hash of the previous record, a timestamp and transaction data which makes it difficult to forge documents and sensitive information of the investor. Another advantage of blockchain is that it is resistant to any type of data modification. Blockchain technology can sort out the security issues and forgery incidents that are faced by the real estate market. Also blockchain provides much meaningful assets and insights to the real estate market at a reasonable and stable-priced market. The proposed solution for the selected problem statement is Tokenizing real estate assets refers to a process in which a property owner can offer digital tokens that represent a share of their property. Using a blockchain to track these investments, with each transaction being time-stamped and immutable, makes it possible to limit the risk of fraud.

Fluid flow in unconventional porous media is extremely complex due to the many physical processes and forces that governs fluid flow, such as diffusion, inertia, viscous flow, and sorption. Furthermore, modeling fluid flow in poor porous media often disregards the mentioned forces, assuming viscous transport is the predominant controller. This work introduces a new comprehensive flow model suitable for tight unconventional reservoirs, including viscous, inertia, diffusion, and sorption forces, to account for fluid transport in the three scales. The new model addresses 1-D linear flow in tight unconventional reservoirs and has been mathematically derived and numerically solved using MATLAB software and tested against a synthetic case study. The new models have been numerically solved and analyzed using synthetic data with previously published models that cater to the same phenomena and analyzed. In addition to studying the flow regimes effecting gas flow in porous media. It has been observed that the diffusion system becomes more prominent in regulating flow velocity with low permeability of the formation rock and low viscosity of the flowing fluid. Additionally, as a result, the sorption mechanism contribution to the flow increases with low permeability of the medium and low viscosity of the flowing fluid as it affects the concentration of gas, leading to release gas from being trapped in pores and rock surfaces.

Kebutuhan teknologi di masa globalisasi saat ini semakin alami perkembangan sangat amat pesat, suatu kemudahan serta moderenisasi sangat dimudahkan guna menunjang bisnis serta kemajuan dari suatu perseroan. Penelitian ini memiliki tujuan yaitu merancang sistem informasi berbasis desktop untuk mendukung pemesanan catering sehingga dapat meminimalisir terjadinya kesalahan dalam pemesanan, hal ini dikarenakan pemesanan yang masih dilakukan dengan di tulis tangan yang membuat kemungkinan terjadinya kekeliruan seperti pesanan yang double, tidak urutnya penerimaan pesanan akibat bertumpuknya nota pesanan pada saat ramai pelanggan yang bisa saja terjadi human error seperti lupa atas pesanan pelanggan. Metode penelitian yang digunakan untuk menganalisis aplikasi yang dibuat adalah observasi dan wawancara. Metode pengembangan sistem menggunakan metode waterfall karena metode ini sangat mudah digunakan untuk melakukan pengembangan. Hasil dari penelitian ini dapat meningkatkan kualitas kerja sehingga dapat mengurangi terjadinya kesalahan dan membuat proses pemesanan catering menjadi lebih cepat, tepat, danakurat.Kata Kunci: Sistem Informasi, Pemesanan Catering, Java

Banyak perusahaan berlomba – lomba menciptakan produk smartphone dengan berbagai jenis, harga, dan fiturfitur menarik didalamnya. Banyaknya pilihan yang ditawarkan membuat konsumen kesulitan dalam mencari smartphone yang sesuai dengan keinginan, sehingga konsumen harus bersusah payah melakukan survei apabila ingin membeli smartphone. Penulis bertujuan membuat sistem pemilihan smartphone terbaik sebagai solusi untuk memudahkan konsumen sebelum membeli smartphone. Metode yang penulis gunakan dalam penelitian ini adalah metode Simple Additive Weighting (SAW), yaitu sebuah metode penjumlahan terbobot dengan mencari rating tiap alternatif yang ada melalui perhitungan berdasarkan bobot kriteria tertentu. Hasil yang diperoleh dalam penelitian ini yaitu menempatkan alternatif A8 sebagai nilai tertinggi dengan hasil nilai 0.982428, yang berarti alternatif A8 sebagai smartphone terbaik dalam penelitian ini.Kata Kunci: Simple Additive Weighting (SAW), Smartphone, Sistem Pengambilan Keputusan, Android, Java

Perkembangan di era teknologi modern, khususnya ilmu teknologi informasi sangat berkembang pesat. Hal ini dikarenakan pemanfaatan teknologi seperti komputer. Lain halnya dengan Arema Combat yang masih menggunakan sistem manual. Usaha ini masih memanfaatkan kertas untuk mencatat transaksi, sehingga pengolahan data yang dilakukan sering terjadi kesalahan dan laporan mengenai hal yang berkaitan dengan pendataan pelanggan, keuangan, serta saat proses transaksinya. Tujuan dibuatnya aplikasi pengolahan data pelanggan ini adalah untuk membantu meningkatkan kinerja karyawan dalam pengolahan data transaksi pelanggan, serta pembuatan laporan yang dapat dikelola dengan efesien dan akurat. Metode penelitani yang digunakan yaitu metodeikualitatif deskriptifimulai dari proses wawancara hinggaiobservasi langsung. Metode pengembangan yang digunakan adalah metode waterfall. Hasil dari penelitian ini sangat membantu karyawan dalam pengolahan data yang tersistematisisehinggan dapat meminimalisir terjadinya kesalahan dalamipengolahan data.Kata Kunci: Aplikasi, Pengolahan Data Pelanggan, Java

Batik Wiryo memiliki usaha yang menjual sebuah maha karya batik tulis, nama Wiryo itu sendiri diambil dari nama ibu pemilik usaha. Batik Wiryo masih menggunakan manual dalam melakukan pendataan dan pengelolaan transaksi, sebab itu penulis membuat sebuah aplikasi yang nantinya untuk memudahkan proses pendataan dan pengolaan transaksi secara efektif, efisien dan penyimpanan data dimasukan ke dalam database. Penelitian ini bertujuan untuk menganalisa sistem yang digunakan pada Batik Wiryo, dan memberikan solusi yang mempermudah dalam melakukan proses transaksi. Oleh karena itu, melalui suatu sistem berkomputer yang diperlukan bisa melewati permasalahan saat ini. Serta memberikan solusi terbaik demi meningkatkan kinerja pegawai dan juga bermanfaat untuk kenyamanan pelanggan. Sekarang bisa dengan mudah dalam melakukan pendataan dan perhitungan transaksi karena data dapat disimpan dalam database sehingga memudahkan admin dalam melakukan pengelolaan transaksi pada Batik Wiryo. Metodologi akan digunakan untuk merancang Sistem Informasi Transaksi dengan menggunakan cara menganalisa data dan investigasi lapangan. Metode pengembangan yang digunakan yaitu model waterfall karena model ini sangat cocok dan mudah untuk melakukan pengembangan. Penyusun juga berharap semoga aplikasi Sistem Informasi Transaksi ini dapat menambah kinerja admin Batik Wiryo. Kata Kunci: Sistem Informasi, Aplikasi Kasir, Java

Laundry umum disebut jasa cuci merupakan hal yang lumrah dikalangan masyarakat pada zaman ini, karena dengan adanya jasa laundry sangat membantu masyarakat yang memiliki kesibukan cukup padat, sehingga tidak perlu lagi memikirkan cucian kotor. Banyaknya masyarakat yang menggunakan jasa laundry membuat pihak laundry kesulitan dalam melakukan pendataan, ditambah lagi jumlah pakaian cukup banyak sehingga kemungkinan terjadinya kesalahan dalam melakukan pendataan dan perhitungan yang kurang akurat. Peneltian yang dilakukan bertujuan untuk meningkatkan kinerja serta memudahkan dalam mengelola data pelanggan dan transaksi serta dalam pembuatan laporan sehingga meminimalkan terjadinya kesalahan dalam pendataan dan perhitungan transaksi. Metode penelitian yang digunakan yaitu metode kualitatif mulai dari tahap wawancara sampai observasi langsung ke lapangan. Metode pengembangan yang digunakan yaitu model waterfall karena model ini sangat cocok dan mudah untuk melakukan pengembangan. Hasil dari penelitian ini sangat bermanfaat untuk meningkat kualitas kerja dan tersistematis sehingga mengurangi terjadinya kesalahan dalam pengolahan data, sehingga data yang dihasilkan akan lebih akurat.Kata Kunci: Sistem Informasi, Pendataan Pelanggan dan Pengelolaan Transaksi, Java

Perkembangan teknologi dan informasi yang berkembang pesat dari tahun ke tahun menuntut di setiap instansi pemerintahan, swasta, maupun lingkup warga untuk mengikuti perkembangan tersebut. Dengan penggunaan sistem secara komputerisasi dan digitalisasi semakin mempermudah instansi dalam melakukan pengolahan data serta lebih efisiensi dan efektivitas kerja. Informasi penduduk merupakan faktor yang penting dalam lingkup Rukun Tetangga karena dengan informasi penduduk tersebut dapat memudahkan dalam pelayanan dan penyuluhan informasi terkait kepada masyarakat setempat. Implementasi sistem komputerisasi dilakukan karena pendataan warga masih menggunakan metode manual atau tulis tangan, belum adanya informasi pendataan balita dalam rangka pemberian imunisasi, terjadi penumpukan berkas-berkas warga setelah pendataan, yang berakibat lamanya pencarian data ketika ingin mengambil atau mencari data warga dan data lain-lain. Penelitian bertujuan untuk menganalisis metode yang digunakan dalam sistem pendataan warga yang berjalan saat ini untuk digantikan dan diimplementasikan menggunakan sistem pendataan secara komputerisasi. Metode kualitatif dan waterfall digunakan dalam metode pengembangan sistem. Wawancara dan observasi dipilih dalam menganalisis metode penelitian yang akan digunakan untuk pengembangan sistem pendataan warga secara komputerisasi. Membantu ketua Rukun Tetangga dan pengurus dalam pengelolaan data warga menjadi simpulan penulis dalam perancangan dan pengembangan sistem pendataan warga secara komputerisasi agar sistem yang penulis ciptakan berguna bagi ketua Rukun Tetangga dan pengurusnya.Kata Kunci: Sistem Pendataan Warga, Teknologi dan Informasi, Metode Waterfall

Pesatnya perkembangan Informatika di era modern sekarang menjadikan Informatika bagian utama dari kehidupan, termasuk di lembaga pemerintah atau swasta, karena sistem memusatkan dan mengontrol semua bagian lembaga. Mengingat perkembangan teknologi yang terus menjadi pesat, juga bermanfaat sebagai media alternatif dalam memudahkan pendataan dan uang kas makam. Tujuan dari perancangan sistem informasi ini adalah menganti sistem lama dalam mengelola pendataan makam dan uang kas menjadi sistem baru yang sudah terkomputerisasi dengan baik sehingga menjadi sistem informasi yang efisien, mempermudah dalam mengelola dan memproses data yang dibutuhkan menjadi lebih cepat dan tepat setiap digunakan. Dengan adanya sistem informasi dapat menyediakan informasi secara akurat dan terjaga keamanan user. Metode penelitian disini menggunakan metode kualitatif, sedangkan dalam metode pengembangan menggunakan metode Waterfall. Hasil dari penelitian ini yaitu mempermudah pendataan makam dan uang kas yang memerlukan kecepatan dan ketepatan informasi.Kata Kunci: Aplikasi Pendataan, Uang Kas, Waterfall.

Lifestyle and nutritional transitions in the society driven by globalization have led to the rising burden of cholelithiasis. The present study was done to assess the impact of lifestyle, stress, menstrual pattern, and cardiometabolic risk factors on young females with cholelithiasis.A hospital-based case-control study was conducted on young females of 18-45 years. Cases and age-matched controls were compared on their lifestyle parameters like demography, marital status, occupation, educational status, family income, stress along with menstrual pattern, cardiometabolic parameters like anthropometric measures, blood pressure (BP), fasting blood sugar (FBS), and lipid profile. Chi-square test and unpaired t-test were used for the analysis of data using SPSS software, andThe majority of the cases were from rural areas, married, homemakers leading a comparatively sedentary lifestyle consuming more red meat, less literate, and belonged to a lower economic group with significantly more stress compared to controls. The age of menarche, neither the regularity nor irregularity of the menstrual cycle (regular cycle 21-35 days), showed any difference, but cases had significantly more pregnancies and usage of oral contraceptives compared to controls. Waist-height ratio, systolic BP, FBS, triglyceride, low-density lipoprotein (LDL), and very low-density lipoprotein (VLDL) were significantly higher in cases. Cases had a 14.4 times more risk of developing metabolic syndrome when compared with controls.Married, rural, less literate Indian women leading a sedentary lifestyle, consuming more of red meat, and soft drinks with increased psychosomatic stress are more prone to develop cholelithiasis. Women who use hormonal contraceptives have increased occurrence of cholelithiasis and they were more prone to develop metabolic syndrome. The need for the hour is health education, to implement simple lifestyle changes, thereby decreasing the incidence of cholelithiasis in young females.

Although gas desorption is a known phenomenon, modeling fluid flow in tight gas reservoirs often ignores the governing desorption effect, assuming that viscous transport is the predominant controller, resulting in an erroneous prediction of mass transport and fluid flow calculations. Thus, developing a new model accommodating all the major contributing forces in such a medium is essential. This work introduces a new comprehensive flow model suitable for tight unconventional reservoirs, including viscous, inertia, diffusion, and sorption forces, to account for fluid transport. Based on Langmuir law and Knudsen diffusion effect, three models were generated and compared with different known models using synthetic data. The model was solved and analyzed for different scenario cases, and parametric studies were conducted to evaluate the desorption effect on different reservoir types using MATLAB. Results show that the contribution of the sorption mechanism to the flow increases with the reducing permeability of the medium and lower viscosity of the flowing fluid and an additional pressure drop up to 10 psi was quantified.

This community service was carried out at Karang Taruna Tunas Karya Kunciran Indah, with the title "PKM Karang Taruna Tunas Karya Kunciran Indah". Based on the results of interviews and observations conducted by the team proposing community service at Karang Taruna Tunas Karya Kunciran Indah, various problems were found in the Karang Taruna Tunas Karya Kunciran Indah, namely requiring a storage media file for data files and reports on all youth activities. easily accessible and secure. Given this problem, the purpose of implementing this community service program is to help make it easier for administrators to archive youth files using Google Drive and manage youth youth cash finances using a cash income and disbursement application that can be installed on each administrator's smartphone and cadet members. This activity uses a learning approach method in which there are presentations, application simulations, and hands-on practice for participants assisted by the team. So that participants can understand and study the material presented properly and can be useful and increase knowledge about storing and managing data for Karang Taruna Tunas Karya Kunciran Indah. Keywords: Google Drive, Apps, Cash In and Out, Android, Finance

It is well known that for the heat equation on a rectangle, the finite difference alternating direction implicit (ADI) method converges with order two. For the first time in the literature, we bound errors of the finite difference ADI method for the heat equation on a convex set for which it is possible to construct a partition consistent with the boundary. Numerical results indicate that the ADI method may also work for some nonconvex sets for which it is possible to construct a partition consistent with the boundary.

A model for single-phase fluid flow in tight UCRs was previously produced by modifying the flow Forchheimer’s equation. The new modification addresses the fluid transport phenomena into three scales incorporating a diffusion term. In this study, a new liner model, numerically solved, has been developed and deployed for a gas huff and puff project. The new model has been numerically validated and verified using synthetic data and huff and puff case study. Ideally, the new model suits fluid flow in tight UCRs. The modified Forchheimer’s model presented is solved using the MATLAB numerical method for linear multiphase flow. For the huff & puff case, very simple profiles and flow dynamics of the main flow parameters have been established and a thorough parametric analysis and verifications were performed. It has been observed that the diffusion system becomes more prominent in regulating flow velocity with low permeability of the formation rock and low viscosity of the flowing fluid. The findings indicate a behavioral alignment with a previous hypothesis that matches actual reservoir behavior.

Architecture provides the material context in which everyday life unfolds. As a material practice, architecture is constantly in flux, responding dynamically to changes in the surrounding environment. The emergence of New Materialism, stemming from Modernist ideas, marks a shift in architecture from a discourse of symbolism and metaphors, towards one of performance and material behaviour. This thesis studies material performance in the context of wood architecture. Wood is a heterogeneous material with unique performative capacities as a result of its biological makeup. This heterogeneity is often viewed as a disadvantage when compared to more uniform materials that behave more predictably. However, when reconsidered, the unique qualities of wood can be used to inform design. This thesis investigates these qualities with a focus on the material’s responsiveness to moisture. In doing so, it attempts to unravel the potential of wood in the advancement of a new wood architecture.

The development of Information and Communication Technology (ICT) is currently growing very rapidly. In the world of education, various kinds of services are now available that support technological developments. In educational institutions, one indicator of success is the application of Information and Communication Technology (ICT), which is now a must. One of the technologies that exist in the world of education, namely one of the e-learning systems. Some of the problems that often arise are in the delivery of learning content. Teachers experience difficulties in delivering or distributing material to students in PKBM. The purpose of this community service is the implementation of e-learning applications to help and be able to simplify and speed up the teaching and learning process at Community College PKBM. This community service activity uses presentation methods, lectures, discussions or a combination of these methods. This e-learning application uses the open source Moodle application. Keywords: E-Learning, Open Source, PKBM, Moodle

Diffusion forces contribution has been heavily underestimated when modeling fluid flow in porous media especially in UCRs with a general agreement that viscous transport is the predominant controller. This work introduces a new comprehensive flow model suitable for tight UCRs, including viscous, inertia, and diffusion forces, to account for the transport of fluid in the three scales. The new model addressing multi-phase 1-D linear flow in tight UCRs has been mathematically derived and numerically solved, and tested against real cases using MATLAB software. Detailed parametric analysis has been conducted, and very clear profiles and flow patterns of the main flow parameters were identified. It has been established that, with lower permeability of the porous medium and lower viscosity of the flowing fluid, the diffusion mechanism becomes more predominant in controlling flow velocity. The results of the newly derived equations that includes the diffusion term clearly depicted the contribution of diffusivity to the flow in the nano-scaled pore spaces. The comparison between the suggested equation to existing equations and correlations that are used in the field to describe the behavior of the flow in low permeability and low porous medium have been established.

This work presents a driver and controller integrated circuit (IC) for depletion-mode gallium nitride (GaN) high-electron-mobility transistors (HEMTs). The dual-mode driver can be configured for cascode-drive (CD) or HEMT-drive (HD) mode. In the CD mode, a cascode low-voltage DMOS is driven to achieve high-speed normally OFF operation. An active clamping circuit is proposed for the DMOS breakdown protection. In the HD mode, an HEMT gate driver with negative drive-voltage capability and programmable slope control is presented. A digital peak current-mode controller is also integrated with the dual-mode driver. The IC was implemented in a 140-nm automotive bipolar-CMOS-DMOS silicon-on-insulator process. The driver/controller IC is copackaged with an optimized 600-V GaN HEMT fabricated in a GaN-on-Si process. The solution was verified to operate at up to 1 MHz in a 35-W boost converter prototype and achieves a programmable switching-node $dv/dt$ of up to 20 V/ns. To the best of the author's knowledge, this is the first monolithic integration of a cascode MOSFET, device driver, and digital current-mode controller that is designed specifically for high-voltage GaN devices.

This work presents a novel mixed-signal control scheme for a boost power factor correction (PFC) rectifier. The digital controller modulates the inductor peak current to produce a low-distortion ac line current in discontinuous conduction mode (DCM) and continuous conduction mode (CCM), without the need for average current sensing. A lookup table (LUT) optimizes efficiency at low input currents, by allowing operation at 125–500-kHz DCM based on calculated thresholds. At high input currents, the converter operates at 1-MHz CCM for reduced inductor footprint. An analog off-time generator with a digital frequency locked loop facilitates CCM operation, eliminating the need for slope compensation in the current loop and reduces frequency variations. The LUT is programmed with an adaptive output voltage of 250/450 V for low/high mains line voltage (85–265 Vrms) to optimize efficiency over a broad range of conditions. The 150-W PFC prototype operates up to 1 MHz with a peak efficiency of 95% and a total harmonic distortion of 5%.

A novel high gain current-driven DC-DC converter topology is proposed in this paper. This circuit is aimed for applications which require wide input and output voltage ranges, such as PV micro-inverters, electric vehicle battery chargers etc. As compared to the resonant converters, the size of inductor can be reduced by an order of magnitude and resonant capacitors eliminated, by the use of current-driven topology. These advantages result in increased power density and higher power conversion efficiency of the converter. A major limitation of the current-driven topology is that it can provide a maximum gain of just over unity. Further, this value of maximum gain also depends on the parasitic capacitances of the converter components. These issues make the converter operation more susceptible to component parasitics (such as the transformer inter-turn capacitance), resulting in degraded converter performance. The high-gain current-driven topology, presented in this paper overcomes the disadvantages of the conventional current-driven converter topology, by the introduction of a parallel capacitor at the high voltage side of the transformer winding. Introduction of parallel capacitor provides a two-fold advantage to the conventional current-driven topology. First it makes the effect of parasitic capacitor small so that the control system is not much sensitive to it, and it provides a high gain due to pre-charging of the network inductances at the beginning of each switching cycle. Simulation and experimental results validate the viability of proposed converter topology for applications requiring wide range of input and output voltages.

This paper describes an integrated power management IC with bidirectional current capability, aimed at compensating differences in output current between series-connected cells in concentrating photovoltaic (CPV) systems. The integrated 3.6-MHz power stage allows building a small-form-factor converter per cell. A hysteretic current-mode controller regulates the bidirectional converter's current to equalize neighboring cell voltages. A phase-locked loop controls the inductor current ripple around the average value to stabilize the switching frequency. The use of hysteretic current-mode control with a novel bidirectional senseFET scheme provides inherent current protection and high reliability. The converter can operate from an input voltage as low as 1.8 V and with an inductor current up to $\pm$ 1.5 A, while achieving a system efficiency above 90% for current mismatches between cells up to 60%. Measurement results show that the converter maximizes the output power of series-connected CPV cells with mismatched output currents.

This paper presents a thermal analysis of a defrost cycle in order to design more efficient defrosting mechanisms in household refrigerators and freezers. A simple heat transfer model has been developed to determine energy flows from a defrost heater across various components of a refrigerator/freezer. The study measures power consumption and temperatures of a single temperature vertical empty freezer (in normal operation with and without defrosts) to determine the heat distribution from the radiant type electric defrost heater and its effect on power consumption. The surface temperature of the defrost heater was measured to be 520 °C for minimal frost and 560 °C for heavy frost. The efficiency of a defrost heater was measured to be 30.3%, while power consumption of the freezer was found to increase by 17.7% due to automatic defrost.

This work presents an intelligent driver IC for 400 V GaN-based Power Factor Correction (PFC) applications. The targeted power level of the converter is 100 W, with a switching frequency above 500 kHz. The IC was implemented in a 140 nm automotive BCD SOI process, while the GaN HEMT and Schottky diode were optimized in a Si-fab compatible GaN-on-Si process. A low-R on DMOS is integrated in the driver IC to achieve high-speed cascode switching operation. The chip also features a novel dual-mode drive scheme with monolithic negative drive voltage capability and programmable slew rate, as well as a digital peak current-mode controller. Advanced digital PFC control schemes can therefore be implemented, while EMC performance and efficiency can be optimized through active slope control.

This work presents a power management IC used to mitigate the effects of mismatch in Concentrating-Photovoltaic (CPV) systems. The IC contains a bi-directional dc-dc converter, an auxiliary boost converter to generate the internal 10 V power supply, as well as protection and monitoring circuits. The main power converter, with a maximum current rating of 1.5 A, is designed to equalize the voltage between neighbouring CPV cells by using the Δ-converter approach. Due to partial power processing, the converter's power rating and efficiency requirements are relaxed, leading to a more cost-effective solution with a high switching frequency of 3.6 MHz. An on-chip, mixed-signal controller regulates the main converter using a digital voltage loop and an analog hysteretic current-mode loop. The IC has several advanced features to reduce the light-load power consumption, including burst-mode operation in both the auxiliary and main-stage converters, as well as an input supply switching scheme for the internal linear voltage regulators.

This work targets low-power portable electronic applications with PV power harvesting. A bidirectional dc-dc converter is required to interface the battery with the load and PV module. A new current-mode scheme is applied to the single-inductor three-port converter, where the peak and valley inductor current are controlled by two separate digital regulation loops. The controller is shown to regulate both the PV voltage and the load voltage in the presence of load and irradiance steps. In solar deficit mode, energy is transferred from the battery to the load indirectly through the PV node, eliminating the two input switches used in conventional dual-input, dual-output converters. The scheme is demonstrated on a digitally controlled 1 W harvester prototype.

Introduction: Penile fracture is a rare but urological emergency which requires expediate surgical treatment for restorement of potency. This condition remains under-reported due to ethical and psychological reasons. Diagnosis of penile fracture is mainly based on clinical features. MRIof thepenisis an expensive test that is not always superior to clinical examination or ultrasound. However, it shows many of the important structures and in particular the high-resolution T(2) sequences show the glans, corpora and the tunica albuginea well. Our aim was to review whether MRI helped in early diagnosis and thereby helping in restoring potency. Material and methods: From May 2009 to October 2013, 6 patients with fracture penis were treated at our institute. Mean age of patients was 32.83 years, range from 24 to 43. All the patients presented after 6 hours of injury. Results: Patients who presented early had good IIEF score at three months compared to those who presented late. MRI helped in diagnosing the fracture in two cases, which would have otherwise been treated conservatively. Conclusions: Rupture of the corpus cavernosum is a rare condition and is generally diagnosed by clinical findings. Emergency surgical exploration and treatment is the best guarantee of good functional and cosmetic result.