Abstract: Techniques are disclosed for storing and retrieving large amounts of data in a non-relational database using sort keys. A server computer system may receive a request for raw data specifying a start timestamp and an end timestamp. The server determines a start key and an end key for performing a query on a distributed non-relational database storing key-value pairs, where the determining is based on the start timestamp and the end timestamp. The server may compare the start key and the end key to a sort key included in row keys of key-value pairs stored in the non-relational database. Based on the comparing, the server retrieves one or more rows of raw data from the non-relational database. The server generates a graphical representation of the one or more rows of raw data retrieved from the non-relational database. The disclosed techniques may advantageously improve the efficiency of a database management system.

Abstract: Techniques are disclosed relating to maintaining a high availability (HA) database. In some embodiments, a computer system receives, from a plurality of host computers, a plurality of requests to access data stored in a database implemented using a plurality of clusters. In some embodiments, the computer system responds to the plurality of requests by accessing data stored in an active cluster. The computer system may then determine, based on the responding, health information for ones of the plurality of clusters, wherein the health information is generated based on real-time traffic for the database. In some embodiments, the computer system determines, based on the health information, whether to switch from accessing the active cluster to accessing a backup cluster. In some embodiments, the computer system stores, in respective clusters of the database, a changeover decision generated based on the determining.

Abstract: Techniques are disclosed relating to maintaining a high availability (HA) database. In some embodiments, a computer system receives, from a plurality of host computers, a plurality of requests to access data stored in a database implemented using a plurality of clusters. In some embodiments, the computer system responds to the plurality of requests by accessing data stored in an active cluster. The computer system may then determine, based on the responding, health information for ones of the plurality of clusters, wherein the health information is generated based on real-time traffic for the database. In some embodiments, the computer system determines, based on the health information, whether to switch from accessing the active cluster to accessing a backup cluster. In some embodiments, the computer system stores, in respective clusters of the database, a changeover decision generated based on the determining.

Abstract: A method for operating a graph database, including receiving, by a computer system, a query to a particular graph database, the query identifying a plurality of vertices of the particular graph database. The method further includes performing, by the computer system, hash operations on two or more of the plurality of vertices to generate respective hash values and dividing, using the respective hash values, the query into a plurality of sub-queries, each corresponding to a subset of the plurality of vertices. The method also includes sending, by the computer system, ones of the plurality of sub-queries to a plurality of database repositories for the particular graph database.

Abstract: Techniques are disclosed relating to maintaining a high availability (HA) database. In some embodiments, a computer system receives, from a plurality of host computers, a plurality of requests to access data stored in a database implemented using a plurality of clusters. In some embodiments, the computer system responds to the plurality of requests by accessing data stored in an active cluster. The computer system may then determine, based on the responding, health information for ones of the plurality of clusters, wherein the health information is generated based on real-time traffic for the database. In some embodiments, the computer system determines, based on the health information, whether to switch from accessing the active cluster to accessing a backup cluster. In some embodiments, the computer system stores, in respective clusters of the database, a changeover decision generated based on the determining.

Abstract: Techniques are disclosed relating to maintaining a high availability (HA) database. In some embodiments, a computer system receives, from a plurality of host computers, a plurality of requests to access data stored in a database implemented using a plurality of clusters. In some embodiments, the computer system responds to the plurality of requests by accessing data stored in an active cluster. The computer system may then determine, based on the responding, health information for ones of the plurality of clusters, wherein the health information is generated based on real-time traffic for the database. In some embodiments, the computer system determines, based on the health information, whether to switch from accessing the active cluster to accessing a backup cluster. In some embodiments, the computer system stores, in respective clusters of the database, a changeover decision generated based on the determining.

Abstract: Techniques are disclosed for storing an arranging data in a database. A method includes a computer system storing, in a database, data indicative of a graph data structure having a plurality of nodes connected by a plurality of edges. The method further includes the computer system determining that a number of edges connected to a first node satisfies a threshold number. In response to the determining, the computer system may store an index in an index row associated with the first node. The index identifies a first row having first and second ranges of values stored in first and second rows, respectively. The values in the first and second rows correspond to edges connected to the first node. The values in the first and second ranges are usable to indicate properties of corresponding ones of the plurality of edges.

Abstract: Techniques are disclosed for storing and retrieving large amounts of data in a non-relational database using sort keys. A server computer system may receive a request for raw data specifying a start timestamp and an end timestamp. The server determines a start key and an end key for performing a query on a distributed non-relational database storing key-value pairs, where the determining is based on the start timestamp and the end timestamp. The server may compare the start key and the end key to a sort key included in row keys of key-value pairs stored in the non-relational database. Based on the comparing, the server retrieves one or more rows of raw data from the non-relational database. The server generates a graphical representation of the one or more rows of raw data retrieved from the non-relational database. The disclosed techniques may advantageously improve the efficiency of a database management system.

Abstract: A device for imaging one dimension nanomaterials is provided. The device includes an optical microscope with a liquid immersion objective, a laser device, and a spectrometer. The laser device is configured to provide an incident light beam with a continuous spectrum. The spectrometer is configured to obtain spectral information of the one dimensional nanomaterials.

Abstract: Systems and methods that describe a graph database system with an online component and an offline component, are provided. Write events that modify a first graph in a real-time graph database included in the online component are received. Graph logs that include changes to the first graph in the real-time graph database caused by the write events are generated. The graph logs are transmitted to an offline component of the graph database system in a chronological order. A second graph in the offline component is modified using the graph logs. The first graph and the second graph are instantiated using a graph schema.

Abstract: Techniques are disclosed relating to maintaining a high availability (HA) database. In some embodiments, a computer system receives, from a plurality of host computers, a plurality of requests to access data stored in a database implemented using a plurality of clusters. In some embodiments, the computer system responds to the plurality of requests by accessing data stored in an active cluster. The computer system may then determine, based on the responding, health information for ones of the plurality of clusters, wherein the health information is generated based on real-time traffic for the database. In some embodiments, the computer system determines, based on the health information, whether to switch from accessing the active cluster to accessing a backup cluster. In some embodiments, the computer system stores, in respective clusters of the database, a changeover decision generated based on the determining.

Abstract: Techniques are disclosed for storing an arranging data in a database. A method includes a computer system storing, in a database, data indicative of a graph data structure having a plurality of nodes connected by a plurality of edges. The method further includes the computer system determining that a number of edges connected to a first node satisfies a threshold number. In response to the determining, the computer system may store an index in an index row associated with the first node. The index identifies a first row having first and second ranges of values stored in first and second rows, respectively. The values in the first and second rows correspond to edges connected to the first node. The values in the first and second ranges are usable to indicate properties of corresponding ones of the plurality of edges.

Abstract: Systems and methods that describe a graph database system with an online component and an offline component, are provided. Write events that modify a first graph in a real-time graph database included in the online component are received. Graph logs that include changes to the first graph in the real-time graph database caused by the write events are generated. The graph logs are transmitted to an offline component of the graph database system in a chronological order. A second graph in the offline component is modified using the graph logs. The first graph and the second graph are instantiated using a graph schema.

Abstract: A method for imaging one dimension nanomaterials is provided. Firstly, one dimension nanomaterials sample, an optical microscope with a liquid immersion objective and a liquid are provided. Secondly, the one dimensional nanomaterials sample is immersed in the liquid. Thirdly, the one dimensional nanomaterials sample is illuminated by an incident beam to generate resonance Rayleigh scattering. Fourthly, the liquid immersion objective is immersed into the liquid to get a resonance Rayleigh scattering (RRS) image of the one dimensional nanomaterials sample. Fifthly, spectra of the one dimensional nanomaterials sample are measured to obtain chirality of the one dimensional nanomaterials sample.

Abstract: A method for assigning chirality of carbon nanotube is provided. Firstly, carbon nanotube sample, an optical microscope with a liquid immersion objective and a liquid are provided. Secondly, the carbon nanotube sample is immersed in the liquid. Thirdly, the carbon nanotube sample is illuminated by an incident beam to generate resonance Rayleigh scattering. Fourthly, the liquid immersion objective is immersed into the liquid to get a resonance Rayleigh scattering (RRS) image of the carbon nanotube sample. Fifthly, spectra of the carbon nanotube sample are measured to obtain chirality of the carbon nanotube sample.

Abstract: A device for imaging one dimension nanomaterials is provided. The device includes an optical microscope with a liquid immersion objective, a laser device, and a spectrometer. The laser device is configured to provide an incident light beam with a continuous spectrum. The spectrometer is configured to obtain spectral information of the one dimensional nanomaterials.

Abstract: A method for imaging one dimension nanomaterials is provided. Firstly, one dimension nanomaterials sample, an optical microscope with a liquid immersion objective and a liquid are provided. Secondly, the one dimensional nanomaterials sample is immersed in the liquid. Thirdly, the one dimensional nanomaterials sample is illuminated by an incident beam to generate resonance Rayleigh scattering. Forthly, the liquid immersion objective is immersed into the liquid to get a resonance Rayleigh scattering (RRS) image of the one dimensional nanomaterials sample. Fifthly, spectra of the one dimensional nanomaterials sample are measured to obtain chirality of the one dimensional nanomaterials sample.

Abstract: A method for assigning chirality of carbon nanotube is provided. Firstly, carbon nanotube sample, an optical microscope with a liquid immersion objective and a liquid are provided. Secondly, the carbon nanotube sample is immersed in the liquid. Thirdly, the carbon nanotube sample is illuminated by an incident beam to generate resonance Rayleigh scattering. Forthly, the liquid immersion objective is immersed into the liquid to get a resonance Rayleigh scattering (RRS) image of the carbon nanotube sample. Fifthly, spectra of the carbon nanotube sample are measured to obtain chirality of the carbon nanotube sample.

Abstract: A method for assigning chirality of carbon nanotube is provided. Firstly, carbon nanotube sample, an optical microscope with a liquid immersion objective and a liquid are provided. Secondly, the carbon nanotube sample is immersed in the liquid. Thirdly, the carbon nanotube sample is illuminated by an incident beam to generate resonance Rayleigh scattering. Forthly, the liquid immersion objective is immersed into the liquid to get a resonance Rayleigh scattering (RRS) image of the carbon nanotube sample. Fifthly, spectra of the carbon nanotube sample are measured to obtain chirality of the carbon nanotube sample.

Abstract: A method for imaging one dimension nanomaterials is provided. Firstly, one dimension nanomaterials sample, an optical microscope with a liquid immersion objective and a liquid are provided. Secondly, the one dimensional nanomaterials sample is immersed in the liquid. Thirdly, the one dimensional nanomaterials sample is illuminated by an incident beam to generate resonance Rayleigh scattering. Forthly, the liquid immersion objective is immersed into the liquid to get a resonance Rayleigh scattering (RRS) image of the one dimensional nanomaterials sample. Fifthly, spectra of the one dimensional nanomaterials sample are measured to obtain chirality of the one dimensional nanomaterials sample.