WaterFlow: Heuristic Normalizing Flow for Underwater Image Enhancement and Beyond

Underwater images suffer from light refraction and absorption, which impairs visibility and interferes the subsequent applications. Existing underwater image enhancement methods mainly focus on image quality improvement, ignoring the effect on practice. To balance the visual quality and application, we propose a heuristic normalizing flow for detection-driven underwater image enhancement, dubbed WaterFlow. Specifically, we first develop an invertible mapping to achieve the translation between the degraded image and its clear counterpart. Considering the differentiability and interpretability, we incorporate the heuristic prior into the data-driven mapping procedure, where the ambient light and medium transmission coefficient benefit credible generation. Furthermore, we introduce a detection perception module to transmit the implicit semantic guidance into the enhancement procedure, where the enhanced images hold more detection-favorable features and are able to promote the detection performance. Extensive experiments prove the superiority of our WaterFlow, against state-of-the-art methods quantitatively and qualitatively.Comment: 10 pages, 13 figure

Mengurus masyarakat Singapura gaya Lee Kuan Yew: satu legasi

Lee Kuan Yew (LKY) negarawan unggul Asia Tenggara yang berjaya menggerakkan tindakan-tindakan pragmatik dengan nilai dan gaya kepimpinan berkesan demi mencapai visi pembangunan Singapura. Memiliki pengalaman politik hampir 60 tahun (1955-2011) menjadikan beliau tokoh politik tanpa tandingan di Singapura dan di Asia Tenggara. Kredibiliti kepimpinannya berjaya membawa masyarakat Singapura berkembang maju dari satu tahap ke satu tahap yang lain. Walaupun meletakkan jawatan sebagai Perdana Menteri pada tahun 1990 namun masih terus relevan di arena politik perdana Singapura apabila dilantik sebagai Menteri Kanan (1990-2004) dan Menteri Mentor (2004-2011). Beliau membimbing Singapura pada sebelum dan selepas Singapura dipisahkan daripada Persekutuan Malaysia (1963-1965). Konsep Malaysian Malaysia nya sangat meresahkan dan menjadi penyebab utama Singapura akhirnya perlu membina negara sendiri. Walau bagaimanapun gagasan Malaysian Malaysia telah bertukar menjadi resipi paling ampuh dalam mengurus masyarakat majmuk di Singapura yang merdeka. Sekali gus membentuk gaya kepimpinannya tersendiri. Penulisan ini cuba melihat sepintas lalu legasi LKY dalam mengurus masyarakat majmuk di Singapura. Secara umumnya, masyarakat majmuk akan menghasilkan pelbagai tuntutan dan perjuangan khususnya terhadap hak dan ketuanan. Persoalan sensitif ini berjaya diuruskan LKY dengan gayanya tersendiri. Pendirian asas LKY, dasar keselamatan, dasar pendidikan dwibahasa, sistem politik, sistem demokrasi, konsep “peluang sama rata”, patriotisme dan pembangunan bangsa Singapura, kepercayaan dan pengurusan agama, ekonomi dan modal insan dan nilai Asia akan dibincangkan satu persatu. Adalah diharapkan satu pengkayaan pengetahuan baru berkaitan pengalaman mengurus sebuah masyarakat dan negara khususnya di Asia Tenggara terhasil bagi tujuan rujukan pada masa akan datang

Solar Air Conditioning with Metal Organic Frameworks

Air conditioning is responsible for 5% of energy consumption in the United States as is increasingly in demand across the world as the global middle class continues to grow in size. During hotter months, electricity used to power cooling systems becomes taxing on electric grids, constituting approximately 40% of peak power demand. Traditional air conditioning (AC) systems are also associated with harmful environmental impacts. Both refrigerants used for cooling and fossil fuels used in power contribute to global warming by acting as green-house gases (GHG). Due to the negative effects associated with emissions, the ultimate goal of this research is to drastically reduce non-renewable energy consumption associated with AC units. Generations of technologies have been developed to address this ongoing issue. An emerging solution involves the integration of metal-organic frameworks (MOFs) sorbents into a solar air conditioning system. Because of MOF properties, this integration allows for a thermally driven cycle without requiring a non-renewable energy input. This thesis is comprised of six chapters geared towards assisting in the determination of the most efficient and effective means of incorporation of MOFs into AC systems. Primarily by conducting an extensive literature review, the third chapter discusses Metal Organic Frameworks in depth for determining the most suitable candidates for this research project. Specific needs for the system are examined with different MOFs that meet the criteria considered. In chapter four, feasibility of integrating MOFs into a membrane through sorption measurements is tested for candidate MOF CAU-10. Chapter five is centered around modeling a MOF-assisted indirect evaporative cooler using EES: Engineering Equation Solver. Modeling outputs give a preliminary understanding of the cooling process and its effect on temperature. Together, these chapters move toward showing the feasibility of operation and its applicability to the field of renewable AC. The study of MOF attributes in Chapter 3 focused on Relative Humidity (RH) at which the MOFs demonstrated a steep water uptake, water adsorption capacity, temperatures for MOF regeneration, long term stability, and cost to synthesize and fabricate. These investigations showed Co2Cl2(BTDD), MIL-101, MIL-100(M), MOF-841, and CAU-10 to be the most promising applicants. Through sorption measurements of MOF material CAU-10 its isotherm demonstrated a capacity at the adsorption step below 0.30 gH2O/gMOF but a maximum capacity over 0.5 gH2O/gMOF. The EES model results showed 80-90% of recycled air provides a supply temperature necessary for indoor cooling below 21 oC. Chapter six summarizes all results and gives recommendations focused on thermodynamic optimization.No embargoAcademic Major: Mechanical Engineerin

Sediment phosphorus flux in Beaver Lake in Northwest Arkansas

Internal phosphorus (P) loading may influence primary production in lakes, but the influence of sediment-derived P has not been well studied in Beaver Lake of Northwest Arkansas. Soluble reactive phosphorus (SRP), dissolved organic P (DOP), and total dissolved P (TDP) sediment-water fluxes were determined using intact sediment cores collected from deepwater environments in the riverine, transition zone, and lacustrine zones of Beaver Lake. The SRP, DOP, and TDP fluxes were also estimated from cores collected from shallow locations in the transition zone. There was a net positive SRP (0.001 – 0.005 µg P cm-2 h-1), DOP (0.005 – 0.01 µg P cm-2 h-1), and TDP (0.005 – 0.01 µg P cm-2 h-1) flux from deepwater sediments into the water column. However, DOP and TDP flux in shallow sediments were net negative (-0.004 and -0.002 µg P cm-2 h-1, respectively), suggesting that the majority of P was moving from water into sediment. The SRP flux from shallow sediments in the transition zone was similar to rates observed in deepwater sediments (0.002 µg P cm-2 h-1). However, the variability among flux rates, sites and depths was high, and therefore no statistical differences were found. Sediment oxygen demand was positively correlated with SRP and DOP flux rates from shallow transition zone sediments suggesting that microbial biomass and activity may have influenced sediment P flux. The P flux from shallow sediments supports approximately 1% to 5% of the daily P demand of phytoplankton. When compared to other lakes, sediment P flux in Beaver Lake appears minimal and is probably not an effective avenue to manage eutrophication in this system

Effect of venting range hood flow rate on size-resolved ultrafine particle concentrations from gas stove cooking

Cooking is the main source of ultrafine particles (UFP) in homes. This study investigated the effect of venting range hood flow rate on size-resolved UFP concentrations from gas stove cooking. The same cooking protocol was conducted 60 times using three venting range hoods operated at six flow rates in twin research houses. Size-resolved particle (10–420 nm) concentrations were monitored using a NanoScan scanning mobility particle sizer (SMPS) from 15 min before cooking to 3 h after the cooking had stopped. Cooking increased the background total UFP number concentrations to 1.3 × 103 particles/cm3 on average, with a mean exposure-relevant source strength of 1.8 × 1012 particles/min. Total particle peak reductions ranged from 25% at the lowest fan flow rate of 36 L/s to 98% at the highest rate of 146 L/s. During the operation of a venting range hood, particle removal by deposition was less significant compared to the increasing air exchange rate driven by exhaust ventilation. Exposure to total particles due to cooking varied from 0.9 to 5.8 × 104 particles/cm3·h, 3 h after cooking ended. Compared to the 36 L/s range hood, higher flow rates of 120 and 146 L/s reduced the first-hour post-cooking exposure by 76% and 85%, respectively. © 2018 Crown Copyright. Published with license by Taylor & Francis Group, LLC

Densely distributed and real-time scour hole monitoring using piezoelectric rod sensors

This study aims to validate a piezoelectric driven-rod scour monitoring system that can sense changes in scour depth along the entire rod at its instrumented location. The proposed sensor is a polymeric slender rod with a thin strip of polyvinylidene fluoride that runs through its midline. Extraction of the fundamental frequency allows the direct calculation of the exposed length (or scour depth) of the slender rod undergoing fluid flow excitation. First, laboratory validation in dry conditions is presented. Second, hydrodynamic testing of the sensor system in a soil-bed flume is discussed. Each rod was installed using a three-dimensional-printed footing designed for ease of installation and stabilization during testing. The sensors were installed in a layout designed to capture symmetric scour conditions around a scaled pier. In order to analyze the system out of steady-state conditions, water velocity was increased in stages during testing to induce different degrees of scour. As ambient water flow excited the portion of the exposed rods, the embedded piezoelectric element outputted a time-varying voltage signal. Different methods were then employed to extract the fundamental frequency of each rod, and the results were compared. Further testing was also performed to characterize the relationship between frequency outputs and flow velocity, which were previously thought to be independent. In general, the proposed driven-rod scour monitoring system successfully captured changing frequencies under varied flow conditions