Review of Person Re-identification Techniques

Person re-identification across different surveillance cameras with disjoint fields of view has become one of the most interesting and challenging subjects in the area of intelligent video surveillance. Although several methods have been developed and proposed, certain limitations and unresolved issues remain. In all of the existing re-identification approaches, feature vectors are extracted from segmented still images or video frames. Different similarity or dissimilarity measures have been applied to these vectors. Some methods have used simple constant metrics, whereas others have utilised models to obtain optimised metrics. Some have created models based on local colour or texture information, and others have built models based on the gait of people. In general, the main objective of all these approaches is to achieve a higher-accuracy rate and lowercomputational costs. This study summarises several developments in recent literature and discusses the various available methods used in person re-identification. Specifically, their advantages and disadvantages are mentioned and compared.Comment: Published 201

What Point-of-Use Water Treatment Products Do Consumers Use? Evidence from a Randomized Controlled Trial among the Urban Poor in Bangladesh

BACKGROUND: There is evidence that household point-of-use (POU) water treatment products can reduce the enormous burden of water-borne illness. Nevertheless, adoption among the global poor is very low, and little evidence exists on why. METHODS: We gave 600 households in poor communities in Dhaka, Bangladesh randomly-ordered two-month free trials of four water treatment products: dilute liquid chlorine (sodium hypochlorite solution, marketed locally as Water Guard), sodium dichloroisocyanurate tablets (branded as Aquatabs), a combined flocculant-disinfectant powdered mixture (the PUR Purifier of Water), and a silver-coated ceramic siphon filter. Consumers also received education on the dangers of untreated drinking water. We measured which products consumers used with self-reports, observation (for the filter), and chlorine tests (for the other products). We also measured drinking water's contamination with E. coli (compared to 200 control households). FINDINGS: Households reported highest usage of the filter, although no product had even 30% usage. E. coli concentrations in stored drinking water were generally lowest when households had Water Guard. Households that self-reported product usage had large reductions in E. coli concentrations with any product as compared to controls. CONCLUSION: Traditional arguments for the low adoption of POU products focus on affordability, consumers' lack of information about germs and the dangers of unsafe water, and specific products not meshing with a household's preferences. In this study we provided free trials, repeated informational messages explaining the dangers of untreated water, and a variety of product designs. The low usage of all products despite such efforts makes clear that important barriers exist beyond cost, information, and variation among these four product designs. Without a better understanding of the choices and aspirations of the target end-users, household-based water treatment is unlikely to reduce morbidity and mortality substantially in urban Bangladesh and similar populations

Ceramic Water Filter for Point-Of-Use Water Treatment in Developing Countries: Principles, Challenges and Opportunities

Drinking water source contamination poses a great threat to human health in developing countries. Point-of-use (POU) water treatment techniques, which improve drinking water quality at the household level, offer an affordable and convenient way to obtain safe drinking water and thus can reduce the outbreaks of waterborne diseases. Ceramic water filters (CWFs), fabricated from locally sourced materials and manufactured by local labor, are one of the most socially acceptable POU water treatment technologies because of their effectiveness, low-cost and ease of use. This review concisely summarizes the critical factors that influence the performance of CWFs, including (1) CWF manufacturing process (raw material selection, firing process, silver impregnation), and (2) source water quality. Then, an in-depth discussion is presented with emphasis on key research efforts to address two major challenges of conventional CWFs, including (1) simultaneous increase of filter flow rate and bacterial removal efficiency, and (2) removal of various concerning pollutants, such as viruses and metal(loid)s. To promote the application of CWFs, future research directions can focus on: (1) investigation of pore size distribution and pore structure to achieve higher flow rates and effective pathogen removal by elucidating pathogen transport in porous ceramic and adjusting manufacture parameters; and (2) exploration of new surface modification approaches with enhanced interaction between a variety of contaminants and ceramic surfaces

Assessing the Implementation of Selected Household Water Treatment and Safe Storage (HWTS) Methods in Emergency Settings

We were commissioned by UNICEF and Oxfam to undertake this study to address two overarching questions: 1) What role, if any, should household water treatment and safe storage (HWTS) play in emergency response (in other words, is HWTS a necessary, effective, and suitable intervention for protecting people affected by emergencies compared to other possible interventions)?; and, 2) What are the factors, if any, associated with feasible, and potentially sustained, implementation of HWTS in response to emergencies (e.g., type of emergency, characteristics of setting and affected population, capacity of responders, types of interventions, nature of programmatic support)? We focused particularly on evaluating HWTS interventions implemented in the acute emergency context, within eight weeks of emergency onset. To answer these questions, we investigated HWTS implementations in four acute emergency contexts between August 2009 and March 2010, including: 1) a cholera outbreak in Jajarkot, Nepal; 2) an earthquake in West Sumatra, Indonesia; 3) a flooding event during a cholera epidemic in Turkana, Kenya; and, 4) an earthquake that caused significant internal displacement in Haiti. These emergencies represented a diverse range of emergency situations, geographical settings, affected population size, and HWTS implementation strategy. In each emergency we conducted the following activities: 1) spatial analysis; 2) household surveys; 3) water quality testing; 4) qualitative interviews with water, sanitation, and hygiene (WASH) responders and logistical staff; and, 5) data collection to characterize response costs. We used microbiological improvement of household water quality as our main indicator of HWTS intervention effectiveness. While we are ultimately interested in the health impact of HWTS interventions, assessing health outcomes directly is not possible in the acute emergency context where rapid assessment is vital and diarrheal disease rates are variable. The potential for health benefits can be reasonably inferred if: 1) the intervention reached the target population at risk of waterborne disease due to reliance on unsafe water (coverage); 2) that population used the HWTS intervention (use); and, 3) as a result of such use, household drinking water met WHO guideline values for microbiological water quality. Using an HWTS option to improve household microbiological water quality from above WHO guidelines values before treatment to below WHO guidelines value after treatment is defined in this report as “effective use”