Crowdsourced Radiomap for Room-Level Place Recognition in Urban Environment

The proliferation of WLAN infrastructures has facilitated numerous indoor localization techniques using WLAN fingerprints. In particular, identifying a room or a place in urban environments could be usefully utilized in many application domains such as ubiquitous health. However, it is not straightforward how to bootstrap such a localization sys-tem because WLAN fingerprints of all places must be available in advance. In this paper, we propose a crowdsourcing approach for indoor place recognition. The key idea is to build an open participatory system through which users can contribute fingerprints. As the database size increases, it can provide place recognition service. We conducted an extensive experimental study at a university campus to demonstrate the performance of the proposed method in terms of recognition accuracy. We also studied key factors that could undermine the crowdsourcing approach such as fingerprint density, incorrect contribution, uneven contribution, and device heterogeneity

Crowdsourced Radiomap for Room-Level Place Recognition in Urban Environment

The proliferation of WLAN infrastructures has facilitated numerous indoor localization techniques using WLAN fingerprints. In particular, identifying a room or a place in urban environments could be usefully utilized in many application domains such as ubiquitous health. However, it is not straightforward how to bootstrap such a localization sys-tem because WLAN fingerprints of all places must be available in advance. In this paper, we propose a crowdsourcing approach for indoor place recognition. The key idea is to build an open participatory system through which users can contribute fingerprints. As the database size increases, it can provide place recognition service. We conducted an extensive experimental study at a university campus to demonstrate the performance of the proposed method in terms of recognition accuracy. We also studied key factors that could undermine the crowdsourcing approach such as fingerprint density, incorrect contribution, uneven contribution, and device heterogeneity

Broad-spectrum gene repression using scaffold engineering of synthetic sRNAs

Gene expression regulation in broad-spectrum range is critical for constructing cell factories and genetic circuits to balance and control system-wide fluxes. Synthetic small regulatory RNAs (sRNAs) effectively regulate gene expression at the translational level by modulating an mRNA-binding chance and sRNA abundance; however, it can control target gene expression only within the limit of the intrinsic repression ability of sRNAs. Here, we systematically mutated a SgrS scaffold as a model sRNA by dividing the Hfq-binding module of the sRNA into the three regions: the A/U-rich sequence, the stem, and the hairpin loop, and examined how efficiently the mutants suppressed DsRed2 expression. By doing this, we found that a scaffold with an altered A/U-rich sequence (CUUU) and stem length and that with altered A/U-rich sequence (GCAC) showed a 3-fold stronger and a 3-fold weaker repression than the original scaffold, respectively. For practical application of altered scaffolds, proof-of-concept experiments were performed by constructing a library of 67 synthetic sRNAs with the strongest scaffold, each one targeting a different rationally selected gene, and using this library to enhance cadaverine production in Escherichia coli, yielding in 27% increase (1.67 g/L in flask cultivation, 13.7 g/L in fed-batch cultivation). Synthetic sRNAs with engineered sRNA scaffolds could be useful in modulating gene expression for strain improvement

Metabolic engineering of microorganisms for the production of natural compounds

Natural products have been attracting much interest around the world for their diverse applications, especially in drug and food industries. Plants have been a major source of many different natural products. However, plants are affected by weather and environmental conditions and their successful extraction is rather limited. Chemical synthesis is inefficient due to the complexity of their chemical structures involving enantioselectivity and regioselectivity. For these reasons, an alternative means of overproducing valuable natural products using microorganisms has emerged. In recent years, various metabolic engineering strategies have been developed for the production of natural products by microorganisms. Here, the strategies taken to produce natural products are reviewed. For convenience, natural products are classified into four main categories: terpenoids, phenylpropanoids, polyketides, and alkaloids. For each product category, the strategies for establishing and rewiring the metabolic network for heterologous natural product biosynthesis, systems approaches undertaken to optimize production hosts, and the strategies for fermentation optimization are reviewed. Taken together, metabolic engineering has enabled microorganisms to serve as a prominent platform for natural compounds production. This article examines both the conventional and novel strategies of metabolic engineering, providing general strategies for complex natural compound production through the development of robust microbial‐cell factories

Metabolic engineering of Escherichia coli for natural product biosynthesis

Natural products are widely employed in our daily lives as food additives, pharmaceuticals, nutraceuticals, and cosmetic ingredients, among others. However, their supply has often been limited because of low-yield extraction from natural resources such as plants. To overcome this problem, metabolically engineered Escherichia coli has emerged as a cell factory for natural product biosynthesis because of many advantages including the availability of well-established tools and strategies for metabolic engineering and high cell density culture, in addition to its high growth rate. We review state-of-the-art metabolic engineering strategies for enhanced production of natural products in E. coli, together with representative examples. Future challenges and prospects of natural product biosynthesis by engineered E. coli are also discussed

Systems metabolic engineering as an enabling technology in accomplishing sustainable development goals

With pressing issues arising in recent years, the United Nations proposed 17 Sustainable Development Goals (SDGs) as an agenda urging international cooperations for sustainable development. In this perspective, we examine the roles of systems metabolic engineering (SysME) and its contribution to improving the quality of life and protecting our environment, presenting how this field of study offers resolutions to the SDGs with relevant examples. We conclude with offering our opinion on the current state of SysME and the direction it should move forward in the generations to come, explicitly focusing on addressing the SDGs