Patent Description:
In many scenarios, a luminaire is provided as part of a lighting network or lighting arrangement that serves to illuminate a space or a plurality of spaces that are adjacent or otherwise linked to each other. On the other hand, a luminaire provided as part of the lighting arrangement may be at least partially controlled based on the presence of one or more persons in (a portion of) the space illuminated by the luminaire such that the lights are switched (and/or kept) on while presence of one or more persons in the space is detected and switched (and/or kept) off while no persons are detected in the space. In a typical solution in this regard, a control entity arranged for controlling at least some aspects of operation of the luminaire receives respective sensor signals from one or more passive infrared (PIR) sensors, determines occupancy or non-occupancy accordingly, and switches/keeps the lights on (at a normal light output level) in response to occupancy and switches/keeps the lights off (or at another low light output level) in response to non-occupancy.

Modern lighting control typically may further employ sensors of other type as further basis for the lighting control. As an example in this regard, the control entity in a luminaire receives respective sensor signals from one or more light sensors that are arranged in the space illuminated by the luminaire and adjusts the light output level of the luminaire at least partially based on observed light level indicated in the respective sensor signals.

Sensor signals such as ones conveying the occupancy information and/or the light level information provide valuable control information that, on one hand, enables the luminaire autonomously adjusting its light output such that sufficient light level is provided in the space in view of current occupancy of the space, while on the other hand enables energy conservation via reducing the light output of the luminaire when no occupancy in the space is detected and/or when the light level is sufficient even without substantial light output from the luminaire.

A traditional solution for lighting control that at least partially relies on the sensor information involves usage of a control entity provided with preprogrammed lighting control logic or lighting control algorithm that in the course of its operation reacts e.g. to respective sensor signals from a presence sensor and/or a light sensor in a predetermined manner. The lighting control logic and any (lighting control) parameters associated therewith are typically defined upon manufacturing the control entity and/or the luminaire via suitable default values that make the luminaire readily applicable in a wide variety of different operating environments. This may be especially useful e.g. in scenarios where the lighting arrangement involves a high number of luminaires, at least some of which are installed in physical locations that may make their manual configuration inconvenient or even (practically) impossible.

On the other hand, while usage of a lighting control logic relying on default values typically serves to ensure general applicability of the luminaire regardless of characteristics of its actual operating environment, quite naturally such preprogrammed lighting control logic is unable to account for actually encountered characteristics of the space in the course of operation of the luminaire in an optimized manner and in many occasions fine-tuning of the lighting control logic and/or lighting control parameters associated therewith may enable improved lighting performance in terms of providing a sufficient light level and/or avoiding excessive energy consumption.

Moreover, in a scenario where a lighting arrangement involves a high number of luminaires, some of which are installed in physical locations that are difficult (or even practically impossible) to reach, deriving a mapping between the luminaires installed in the space(s) the lighting arrangement serves to illuminate and the (planned) positions of the luminaires in the floorplan or in other visual representation of the space(s) may be tedious process that requires a lot of manual work and is prone to errors -while on the other hand such mapping is typically invaluable e.g. for subsequent maintenance operations of the lighting arrangement.

In related art, <CIT> discloses a luminaire, a system and a method for adaptive illumination for illuminating a surrounding area with increased energetic efficiency, higher flexibility and improved user convenience, wherein the illumination is autonomously adapted according to changing requirements, wherein an activity sensor unit senses activity data in the surroundings of an illumination unit, a control unit generates a history of the activity data sensed for a predetermined time and adjusts operation characteristics of the illumination unit based on the history of activity data for illuminating the surroundings.

Further in related art, <CIT> discloses an equipment information acquirer that acquires, from electric equipment connected to a network, equipment type information indicating the type of electric equipment and at least one of environment information and operation information. A display controller causes the equipment type information acquired by the equipment information acquirer and correlation support information based on at least one of the environment information and the operation information to be displayed on a monitor after correlating the two with each other. The environment information indicates the environment of an area in which the electric equipment is installed. The operation information indicates the operating status of the electric equipment.

It is an object of the present invention to provide a technique that facilitates automatically or semiautomatically classifying and/or grouping a plurality of luminaires installed in their operating environment.

According to an example embodiment, a method for classifying a plurality of luminaires based on respective sensor data captured at respective locations of the plurality of luminaires that are arranged for illuminating a plurality of spaces is provided, the method comprising: obtaining the respective sensor data for the plurality of luminaires, the respective sensor data for each luminaire comprising respective one or more time series of sensor values that each represent a respective environmental characteristic at the respective location of said plurality of spaces as a function of time for a respective one of the plurality of luminaires; and assigning at least one of the plurality of luminaires into one of two or more predefined luminaire classes based on variation of the sensor values in the respective one or more time series of sensor values in the sensor data obtained for the respective luminaire, wherein said assignment comprises deriving, for each of the plurality of luminaires, based on at least one time series of sensor values included in the sensor data obtained for the respective luminaire, a respective change rate parameter that is descriptive of a change rate of sensor values in said at least one time series of sensor values, and assigning at least one of the plurality of luminaires into one of said two or more predefined luminaire classes based on the change rate parameter derived for the respective one of the plurality of luminaires, wherein said one or more time series of sensor values included in the sensor data obtained from the respective luminaire represents at least one of the following environmental characteristics: carbon dioxide level, respective volatile organic compound (VOC) level for one or more VOCs, humidity, air pressure.

According to another example embodiment, an apparatus comprising analysis means for classifying a plurality of luminaires based on respective sensor data captured at respective locations of the plurality of luminaires that are arranged for illuminating a plurality of spaces is provided, the analysis means arranged to: obtain the respective sensor data for the plurality of luminaires, the respective sensor data for each luminaire comprising respective one or more time series of sensor values that each represent a respective environmental characteristic at the respective location of said plurality of spaces as a function of time for a respective one of the plurality of luminaires; and assign at least one of the plurality of luminaires into one of two or more predefined luminaire classes based on variation of the sensor values in the respective one or more time series of sensor values in the sensor data obtained for the respective luminaire, wherein the analysis means is arranged to carry out said assigning via deriving, for each of the plurality of luminaires, based on at least one time series of sensor values included in the sensor data obtained for the respective luminaire, a respective change rate parameter that is descriptive of a change rate of sensor values in said at least one time series of sensor values, and assigning at least one of the plurality of luminaires into one of said two or more predefined luminaire classes based on the change rate parameter derived for the respective one of the plurality of luminaires, wherein said one or more time series of sensor values included in the sensor data obtained from the respective luminaire represents at least one of the following environmental characteristics: carbon dioxide level, respective volatile organic compound (VOC) level for one or more VOCs, humidity, air pressure.

According to another example embodiment, a computer program for classifying a plurality of luminaires based on respective sensor data captured at respective locations of the plurality of luminaires is provided, the computer program comprising computer readable program code configured to cause performing at least the method according to the example embodiment described in the foregoing when said program code is executed on a computing apparatus.

The computer program according to the above-described example embodiment may be embodied on a volatile or a non-volatile computer-readable record medium, for example as a computer program product comprising at least one computer readable non-transitory medium having the program code stored thereon, which, when executed by a computing apparatus, causes the computing apparatuses at least to perform the method according to the example embodiment described in the foregoing.

Some features of the invention are set forth in the appended claims. The invention relates to a method of classifying a plurality of luminaires according to claim <NUM>, a computer program according to claim <NUM> and an apparatus according to claim <NUM>. Aspects of the invention, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of some example embodiments when read in connection with the accompanying drawings.

<FIG> illustrates a block diagram of some logical components of a lighting arrangement <NUM> according to an example, including a plurality of lighting units <NUM>-<NUM>, <NUM>-<NUM>,. , <NUM>-<NUM>, a lighting control gateway <NUM> and a lighting control server <NUM>. The lighting units <NUM>-<NUM> to <NUM>-<NUM> represent a plurality of (i.e. two or more) lighting units, where an individual lighting unit may be referred to via a reference number <NUM>-k. The lighting units <NUM>-k are communicatively coupled to the lighting control gateway <NUM> and to each other. The communicative coupling may be provided via wired or wireless communication medium, e.g. via a wireless communication network and/or via respective wireless links. The lighting units <NUM>-k and the lighting control gateway <NUM> may be considered as nodes of a lighting network. The lighting control gateway <NUM> is communicatively coupled to the lighting control server <NUM>, e.g. via a communication network such as the Internet. The lighting network is hence coupled to the lighting control server <NUM> via the lighting control gateway <NUM>.

The lighting arrangement <NUM> may be arranged for illuminating respective portions or areas of a space or for illuminating respective one or more spaces that are adjacent or otherwise close to each other. As a few non-limiting examples, a space illuminated by the lighting arrangement <NUM> may comprise an indoor space of a building, such as a room (e.g. an habitable room, an office room, a meeting room, a classroom, an auditorium, etc.), an open space (an open office space, a lobby, a cafeteria, a retail store, etc.) or an intermediate space (such as a corridor, a stairway, etc.). <FIG> illustrates lighting units <NUM>-k of the lighting arrangement <NUM> arranged for illumination of three adjacent spaces of an office building according to a non-limiting example, which space in this example comprises a corridor, a meeting room and office room adjacent to each other and to the corridor with respective single doors linking the two rooms to the corridor. In this example, the lighting arrangement <NUM> comprises lighting units <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM>, each arranged for illuminating a respective portion of the meeting room, a lighting unit <NUM>-<NUM> arranged for illuminating the office room and lighting units <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM>, each arranged for illuminating a respective portion of the corridor.

<FIG> illustrates a block diagram of some logical components of a lighting unit <NUM>-k according to an example. The lighting unit <NUM>-k comprises a luminaire <NUM>-k and a sensor unit <NUM>-k that is coupled to the luminaire <NUM>-k, e.g. via a respective wired connection. The luminaire <NUM>-k comprises a lighting control device <NUM>-k and at least one light source <NUM>-k. The lighting control device <NUM>-k comprises a lighting control means (e.g. a lighting control portion) for controlling the light output from the at least one light source <NUM>-k, an adaptation means (e.g. an adaptation portion) for adjusting operation of the lighting control means and a communication means (e.g. a communication portion) for wired or wireless communication with other devices, e.g. with respective lighting control devices <NUM> of other luminaires <NUM> and/or with the lighting control gateway <NUM> (i.e. with other nodes of the lighting network). The lighting control device <NUM>-k is arranged to control light output of the luminaire <NUM>-k based at least in part on information received from the sensor unit <NUM>-k and/or on information received from other luminaires <NUM> via the communication means.

In a non-limiting example, the at least one light source <NUM>-k comprises one or more light emitting diodes (LEDs) and the lighting control device <NUM>-k comprises or is provided as a LED driver device, whereas in another non-limiting example the at least one light source <NUM>-k comprises one or more fluorescent lamps and the lighting control device <NUM>-k comprises or is provided as an electronic ballast.

The sensor unit <NUM>-k comprises a plurality of sensors, e.g. a plurality of separate sensors that conceptually constitute the sensor unit <NUM>-k, a sensor assembly comprising the plurality of sensors, or a combination of one or more separate sensors and a sensor assembly comprising one or more sensors. Depending on the arrangement, the sensor unit <NUM>-k may comprise one or more sensors that are provided as part of the luminaire <NUM>-k (e.g. arranged in the same housing with the luminaire <NUM>-k) and/or one or more sensor provided separately from (the housing of) the luminaire <NUM>-k (e.g. in a separate sensor assembly and/or as separate sensors).

The plurality of sensors included in the sensor unit <NUM>-k comprises sensors that are arranged for capturing respective sensor signals for provision to the control means in lighting control device <NUM>-k. When referring to the luminaire unit <NUM>-k or components thereof, these sensor signals may be referred to as local sensor signals due to their occurrence locally at the lighting unit <NUM>-k. Each sensor signal is descriptive of a respective environmental characteristic in (the portion of) the space the luminaire <NUM>-k serves to illuminate.

The plurality of sensors included in the sensor unit <NUM>-k typically comprise an occupancy sensor for monitoring an occupancy status (e.g. one of occupancy or non-occupancy) in (the portion of) the space the luminaire <NUM>-k serves to illuminate and a light sensor for observing ambient light level in (the portion of) the space the luminaire <NUM>-k serves to illuminate. As non-limiting examples, the occupancy sensor may comprise a motion sensor such as passive infrared (PIR) sensor and/or the light sensor may comprise a photodetector such as a photodiode. The respective sensor signal from the occupancy sensor and/or the light sensor may be employed by the control means in the lighting control device <NUM>-k for adjusting the light output of the at least one light source <NUM>-k in dependence of the observed occupancy status and/or the observed ambient light level. The PIR sensor, however, is a non-limiting example of an applicable type of occupancy sensor, while other examples include a microwave radar, a (digital) camera, a thermographic camera, a microphone, a lidar, etc..

The plurality of sensors included in the sensor unit <NUM>-k may further comprise, for example, one or more of the following sensors:.

Referring back to the one or more VOC sensors described in the foregoing, the monitored VOCs may include one or more of following: particulate matter (PM) such as PM<NUM> and/or PM<NUM>, CO<NUM>, carbon monoxide (CO), ozone (Os), nitrogen dioxide (NO<NUM>), formaldehyde, total VOC concentration (TVOC).

Sensors of such type enable obtaining information on respective environmental characteristics in (the portion of) the space the luminaire <NUM>-k serves to illuminate and hence the information obtained in the respective sensor signals may be applied in the lighting control device <NUM>-k e.g. by the control means as further input for adjusting the light output from the luminaire <NUM>-k.

The lighting control device <NUM>-k, e.g. the lighting control means therein, may be preprogrammed (or otherwise provided) with a lighting control logic that defines the manner of controlling the light output from the luminaire <NUM>-k at least in part in dependence of local sensor signals received at the lighting control device <NUM>-k. The preprogrammed lighting control logic may define one or more pairs of a predefined triggering condition and a lighting control action to be carried out as a response to an occurrence of the predefined triggering condition. Each such pair may be referred to as a respective lighting control rule and hence the lighting control logic may comprise one or more lighting control rules. A lighting control rule may, optionally, have one or more lighting control parameters associated therewith. As non-limiting examples concerning lighting control rules, a lighting control rule may define a triggering condition that directly or indirectly pertains to the local occupancy sensor signal and/or a triggering condition that directly or indirectly pertains to the local light sensor signal. The light output control provided by the lighting control device <NUM>-k may substantially follow from the lighting control means therein implementing one or more lighting control rules of the lighting control logic defined for the lighting control device <NUM>-k. However, for brevity and clarity of the description, in the following lighting control actions arising from implementation of the lighting control logic are predominantly described as operations carried out by the lighting control device <NUM>-k.

Non-limiting examples of lighting control rules comprise a lighting control rule that defines switching on the light output from the luminaire <NUM>-k at a respective target light intensity Itgt,k or otherwise adjust the light output from the luminaire <NUM>-k from a lower light intensity to the target light intensity Itgt,k as a response to a change in occupancy status from non-occupancy to occupancy, a lighting control rule that defines adjusting the light output from the luminaire <NUM>-k to a respective stand-by light intensity Ioff,k as a response to a change of occupancy status from occupancy to non-occupancy followed by a switch-off delay period Toff,k without a change of occupancy status from non-occupancy to occupancy, and/or a lighting control rule that defines adjusting the light output from the luminaire <NUM>-k to a respective intermediate light intensity Idim,k where (Ioff,k < Idim,k < Itgt,k) as a response to a change of occupancy status from occupancy to non-occupancy followed by a dim-down delay period Toff,k where (Tdim,k < Toff,k) without a change of occupancy status from non-occupancy to occupancy.

The target light intensity Itgt,k, the intermediate light intensity Iint,k and the stand-by light intensity Ioff,k as well as the switch-off delay period Toff,k, the dim-down delay period Tdim,k described above serve as non-limiting examples of lighting control parameters that may be defined for the lighting control rules of the lighting control logic. The lighting control parameters associated with at least some of the lighting control rules of the preprogrammed lighting control logic may be initially set to respective default values. As described in the foregoing, these lighting control parameters may be initially set to respective default values that make the luminaire <NUM>-k readily applicable in a wide variety of different operating environments and operating conditions. Such setting of the lighting control parameters may be carried out, for example, upon manufacturing the luminaire <NUM>-k and/or the lighting control device <NUM>-k of the luminaire <NUM>-k. The lighting control logic, including the lighting control parameters, may be provided e.g. as program code stored in a memory in the lighting control device <NUM>-k that will be executed by a processor in the lighting control device <NUM>-k in the course of its operation.

As described in the foregoing, the lighting control device <NUM>-k comprises the communication means to enable wired or wireless communication between the control device <NUM>-k and other devices, e.g. the other nodes of the lighting network. As a non-limiting example, the communication means in the lighting control device <NUM>-k may comprise a wireless transceiver that is capable of communicating with wireless transceivers in respective lighting control devices <NUM> of other luminaires <NUM> and with a wireless transceiver in the lighting control gateway <NUM> using a wireless communication technique or protocol. The wireless communication may be provided by using a suitable short-range wireless communication technique known in the art that enables communication over ranges from a few meters up to a few hundred meters. Examples of suitable wireless communication techniques include Bluetooth, Bluetooth Low-Energy (LE), ZigBee, WLAN/Wi-Fi according to an IEEE <NUM> family of standards, etc. Further examples include infrared communications and other non-radio-based short-range communication techniques.

The choice of the communication technique and network topology for a specific embodiment of the lighting arrangement <NUM> may depend e.g. on the required communication range and/or requirements with respect to energy-efficiency of the communication means. As a concrete non-limiting example, the wireless communication may rely on a wireless mesh network model, for example on a mesh network according to the Bluetooth or Bluetooth LE Mesh networking protocol known in the art.

The lighting control device <NUM>-k may apply the communication means to transmit status indication messages to the other nodes of the lighting network. Such a status indication message may comprise, in addition to information defined by the applied communication protocol, one or more status indications that are descriptive of current (or recent) operating characteristic of the luminaire <NUM>-k and/or the lighting control device <NUM>-k transmitting the status indication message. Conversely, the lighting control device <NUM>-k receives status indication messages (and hence status indications) from other lighting control devices of the lighting arrangement <NUM>. A status indication transmitted from the lighting control device <NUM>-k may comprise an action indication that identifies a lighting control action taken by the lighting control device <NUM>-k, e.g. switching on the light output from the luminaire <NUM>-k (e.g. the target light intensity Itgt,k), adjusting the light output from the luminaire <NUM>-k to the intermediate light intensity Idim,k, or adjusting the light output from the luminaire <NUM>-k to the stand-by light intensity Ioff,k.

In the course of its operation, the lighting control device <NUM>-k (e.g. the adaptation means) may be arranged to capture or derive respective sensor indications based on information carried in the sensor signals received from the sensor unit <NUM>-k. The lighting control device <NUM>-k may further store, in a memory therein, the sensor indications captured or derived based the information carried in the sensor signals received from the sensor unit <NUM>-k. Such stored data may be referred to as history data and it may comprise, depending on the sensors included in the sensor unit <NUM>-k, one or more of the following:.

In addition to the sensor data obtained or derived based on respective sensor signals received from the sensors of the sensor unit <NUM>-k, the history data may further comprise auxiliary environmental information, such as a history of radio noise level measured at the communication means, stored e.g. at respective predefined time intervals and/or radio frequencies applied for communication (assuming the communication means relies on wireless communication between the nodes of the lighting network).

The history information stored in the memory may cover a predefined time period and the indications included in the history data may be stored together with respective timing information that indicates the capturing time of the respective piece of stored data. The timing information may comprise, for example, a respective timestamp that indicates the time with respect to a predefined reference time.

The lighting control device <NUM>-k (e.g. the adaptation means) may be arranged to, in the course of its operation, make at least some of the sensor indications captured or derived based on the sensor signals received from the sensor unit <NUM>-k available to the lighting control gateway <NUM>. This may involve using the communication means in the lighting control device <NUM>-k to transmit the sensor indications in one or more sensor indication messages to the lighting control gateway <NUM> over the wired or wireless communication network or communication link. Each sensor indication message comprises, in addition to information defined by the applied communication protocol, at least one sensor indication, possibly together with an indication of the underlying sensor type and timing information that defines capturing time of the at least one sensor indication. A sensor indication message may comprise multiple sensor indications that may be captured or derived based on sensor signals of different types.

In an example, the lighting control device <NUM>-k (e.g. the adaptation means therein) is arranged to transmit a sensor indication captured or derived based on a given sensor signal each time a new sensor indication based on the given sensor signal is derived in the lighting control device <NUM>-k. In another example, the lighting control device <NUM>-k transmits one or more sensor indications (pertaining to one or more sensor signals) according to predefined schedule, e.g. at predefined time intervals. A sensor indication message conveying the at least one sensor indication may further comprise a device identifier assigned to the lighting control device <NUM>-k (or to the luminaire <NUM>-k) that has transmitted the at least one sensor indication, in other words an identification of the luminaire <NUM>-k to which the sensor indication(s) pertain. The device identifier may comprise, for example, an address, a serial number, a name, etc. assigned to the lighting control device <NUM>-k (or that assigned to the luminaire <NUM>-k) or to the communication means therein.

The lighting control gateway <NUM> may comprise a computer device provided with a communication means that is able to communicate with the respective communication means in the lighting control devices <NUM> of the luminaires <NUM>. The lighting control gateway <NUM> is to be construed as a logical entity that may be provided as an entity (physically) separate from the luminaires <NUM> of the lighting network or it may be provided as part of one of the luminaires <NUM> or luminaire units <NUM> of the lighting network. The lighting control gateway <NUM> is arranged to receive respective sensor indication messages from a plurality of lighting control devices <NUM> (and hence from the plurality of luminaires <NUM>). The lighting control gateway <NUM> may be arranged to store the sensor indications received in the sensor indication messages in a memory provided in the lighting control gateway <NUM>. Such stored data may be referred to as composite history data and it comprises respective time series of sensor indications for one or more sensor types originating from the plurality of luminaires <NUM>. The lighting control gateway <NUM> may be further arranged to provide the sensor indications stored in the composite history data to the lighting control server <NUM> for storage and analysis therein. The provision of the composite history data from the lighting control gateway <NUM> to the lighting control server <NUM> may involve, for example, the lighting control gateway <NUM> transmitting sensor indications included in the composite history data in one or more composite sensor indication messages, the lighting control gateway <NUM> uploading the composite history data to the lighting control server <NUM> or the lighting control server <NUM> downloading the composite history data from the lighting control gateway <NUM>.

The lighting control server <NUM> is a logical entity that may be provided by one or more computer devices that may be arranged to provide a cloud computing service. The lighting control server <NUM> comprises an analysis means (e.g. an analysis portion) for processing the sensor indications received from the lighting control gateway <NUM>. In this regard, the analysis means may be arranged to store the sensor indications received from the lighting control gateway <NUM> into a memory in the lighting control server <NUM> and to carry out an analysis of the sensor indications received from the lighting control gateway <NUM>. The sensor indications originating from the luminaire <NUM>-k may be arranged by the analysis means into sensor data for the luminaire <NUM>-k that comprises (reconstructed) time series of sensor indications originally captured at the lighting control device <NUM>-k based on the sensor signals received from the sensor unit <NUM>-k, whereas similar arrangement of sensor indications into respective sensor data may be provided for sensor indications received from other luminaires <NUM> of the lighting arrangement <NUM>. The sensor indications may be also referred to as sensor values or sensor readings.

The respective sensor data for the luminaire <NUM>-k hence comprises at least a respective first time series of sensor values that represents a first environmental characteristic as a function of time for the luminaire <NUM>-k. The sensor data for the luminaire <NUM>-k may further comprise respective one or more further time series of sensor values, each representing a respective environmental characteristic that is different from the first environmental characteristics and from each other. Hence, the sensor data may further comprise a respective second time series of sensor values that represents a second environmental characteristic as a function of time, a respective third time series of sensor values that represents a third environmental characteristic as a function of time etc. depending on the number and types of sensors available in the sensor unit <NUM>-k. Herein, the possible second, third and any further environmental characteristics are different from each other.

Along similar lines, the respective sensor data obtained (at the analysis means) for the other luminaires <NUM> comprises at least a respective first time series of sensor indications that represents the first environmental characteristic as a function of time for the respective one of the other luminaires <NUM> and it may further comprise respective one or more further time series of sensor values, each representing the respective environmental characteristic. In other words, the respective first time series of sensor values in the respective sensor data for each of the luminaires <NUM> pertains to the same environmental characteristics, thereby enabling comparison of that environmental characteristic and changes thereof observed at the location of the luminaire <NUM>-k to those observed at respective locations of the other luminaires <NUM> of the lighting arrangement <NUM>. The same applies for possible second, third, etc. time series of sensor values that may be included in the respective sensor data for each of the luminaires <NUM>.

The analysis serves to classify the plurality of luminaires <NUM> based on the respective sensor data captured at respective locations of the plurality of luminaires <NUM> and the analysis may be carried out, for example, in accordance with a method <NUM> illustrated by the flowchart depicted in <FIG>. The analysis is carried out in the course of operation of the lighting arrangement <NUM>, the analysis thereby serving to classify the plurality of luminaires <NUM> operated in their actual locations in the space(s) they serve to illuminate. In this regard, the analysis may be carried out substantially continuously or according to a predefined schedule (e.g. at predefined time intervals).

The analysis according to the method <NUM> may comprise analyzing the respective sensor data obtained for the plurality of luminaires <NUM> for a time period of interest, which may be referred to as an analysis period or as an analysis window. Hence, the analysis may consider a respective sub-series that corresponds to the analysis window in each time series of sensor values of interest across the respective sensor data obtained for the plurality of luminaires <NUM>. The operations described with references to blocks <NUM> to <NUM> pertaining to the method <NUM> may be varied or complemented in a number of ways, for example as described in the foregoing and/or in the following with references to elements of the lighting arrangement <NUM>.

The method <NUM> commences by obtaining the respective sensor data for the plurality of luminaires <NUM>, the respective sensor data for each luminaire <NUM> comprising at least a respective first time series of sensor values that represents the first environmental characteristic as a function of time for a respective one of the plurality of luminaires <NUM>, as indicated in block <NUM>. In this regard, the aspect of obtaining the respective sensor data for the plurality of luminaires <NUM> is described in the foregoing. The method <NUM> further comprises assigning at least one of the plurality of luminaires <NUM> into one of two or more predefined luminaire classes based on variation of the sensor values in the respective sensor data obtained for the respective luminaire <NUM>, as indicated in block <NUM>. The assignment of the luminaires into the two or more luminaire classes may be also referred to as classification of luminaires or luminaire classification.

Referring back to operations described with references to block <NUM>, the assignment that relies on variation of the sensor values may comprise deriving, for each luminaire <NUM> under consideration and for at least one time series of sensor values available in the sensor data provided for the respective one of the luminaires <NUM>, respective one or more change parameters that are descriptive of a respective aspect of variation of the sensor values in the respective time series of sensor values, and assigning at least one of the luminaires <NUM> into one of the two or more predefined luminaire classes based on the change parameters derived for the respective one of the luminaires <NUM>.

The one or more change parameters comprises a change rate parameter that is descriptive of a change rate of sensor values in the respective time series. Consequently, the assignment of at least one of the luminaires <NUM> into one of the two or more predefined luminaire classes comprises deriving a respective change rate parameter for each luminaire under consideration based on at least one time series of sensor data available in the sensor data provided for the respective one of the luminaires <NUM>, and assigning at least one of the luminaires <NUM> into one of the two or more predefined luminaire classes at least based on the change rate parameter(s) derived for the respective one of the luminaires <NUM>.

Still referring to the example pertaining to the change rate parameter, the change-rate-parameter based assignment with respect to a luminaire <NUM>-k may comprise one or both of the following:.

As an example, the first and second predefined luminaire classes may represent luminaires operated in spaces of different types, e.g. such that the first predefined luminaire class represents luminaires operated in an enclosed space such as a room, which may be an habitable room, an office room, a meeting room, a classroom, etc. (where the environmental characteristics represented by the sensor values under consideration typically change relatively fast) and the second predefined luminaire class represents luminaires operated in an open space such as an open office space, a lobby, a corridor, a stairway, a cafeteria, etc. (where the environmental characteristics represented by the sensor values under consideration typically change relatively slowly).

In an example, the first and second change rate thresholds may be set to the same value, thereby defining exactly two predefined luminaire classes and, consequently, resulting in classification of each luminaire either into the first luminaire class or into the second luminaire class based on the change rate derived therefor. In another example, the second change rate threshold is set to a smaller value than the first change rate threshold, thereby implicitly providing a third luminaire class where the change rate derived for the luminaire under consideration falls between the first and second thresholds. Such third luminaire class may represent, for example, a third predefined luminaire class or it may represent luminaires for which the change-rate-based classification does not provide unambiguous classification into one of the first and second luminaire classes. In some examples, the third luminaire class may be further divided into two or more further classes by respective predefined change rate thresholds.

The first and second (and possible further) change rate thresholds are set separately for each time series of sensor values included in the respective sensor data provided for the luminaires <NUM>, in dependence of the environmental characteristics represented by the respective time series. According to an example, the first and second (and possible further) change rate thresholds for a time series representing an environmental characteristic of a given type may be defined based on the sensor values obtained for the respective time series of sensor values over the plurality of the luminaires <NUM>. As an example in this regard, a respective threshold value pertaining to given time series (and hence to a given environmental characteristic) may be defined based on one or more statistical measures, such as an average, a median and/or standard deviation, computed based on sensor values of the respective time series across the plurality of luminaires <NUM>. According to another example, the first and second (and possible further) change rate thresholds for a time series representing an environmental characteristic of a given type may be defined as respective predefined thresholds, for example, based on experimental data (e.g. sensor values) recorded using a sensor observing the environmental characteristic of the given type in operating conditions that correspond to first and second (and possible further) luminaire classes. As an example, the sensor data for a given luminaire <NUM>-k may include a first time series of sensor values that represents the CO<NUM> level as a function of time for the given luminaire <NUM>-k and a second time series of sensor values that represents a VOC level as a function of time for the given luminaire <NUM>-k and, consequently, the first and second (and possible further) change thresholds for the first time series of sensor values are defined in view of expected CO<NUM> levels for the luminaires in the first and second luminaire classes whereas the first and second (and possible further) change thresholds for the second time series of sensor values are defined in view of expected VOC levels for the luminaires in the first and second luminaire classes.

As another example of such change parameters, the one or more change parameters may comprise a value range parameter that is descriptive of a dynamic range of sensor values in the respective time series. Consequently, the assignment of at least one of the luminaires <NUM> into one of the two or more predefined luminaire classes may comprise deriving a respective value range parameter for each luminaire under consideration based on at least one time series of sensor data available in the sensor data provided for the respective one of the luminaires <NUM>, and assigning at least one of the luminaires <NUM> into one of the two or more predefined luminaire classes at least based on the value range parameter(s) derived for the respective one of the luminaires <NUM>.

Still referring to the example pertaining to the value range parameter, the change-rate-parameter based assignment for a luminaire <NUM>-k may comprise one or both of the following:.

The considerations with respect to the types of luminaires represented by the first and second luminaire classes discussed in the foregoing with references to the change-rate-based classification apply to the value-range-based classification as well: in enclosed spaces the environmental characteristics represented by the sensor values under consideration typically have a relatively wide value range, whereas in open spaces they typically have a relatively narrow value range). Moreover, the considerations with respect to selection and/or definition of the first and second (and possible further) change rate thresholds provided in the foregoing for the change rate parameter apply to the value-range-based classification as well, mutatis mutandis.

In an example, multiple change parameters may be applied as basis for the classification of the luminaires <NUM>. Such change parameters may include, for example, respective one or more change rate parameters derived for each luminaire <NUM> under consideration, and/or respective one or more value range parameters derived for each luminaire <NUM> under consideration, possibly together with respective one or more change parameters of other type derived for each luminaire <NUM> under consideration. In this scenario there may be respective two or more change parameters derived for each of the luminaires <NUM>, and the luminaires <NUM> may be assigned into one of the two or more predefined luminaire classes based on the respective two or more parameters derived therefor. The two or more change parameters may be applied in the classification of a given luminaire <NUM>-k into one of the two or more predefined luminaire classes, for example, in the following manner:.

Hence, an example of the threshold-based luminaire classification generalizes into an approach where the given luminaire <NUM>-k is assigned into a first predefined luminaire class in response to at least a predefined number of change parameters derived therefor exceeding a respective first change threshold and where the given luminaire <NUM>-k is assigned into a second predefined luminaire class in response to at least said predefined number of change parameters defined therefor failing to exceed a respective second change threshold, which second change threshold is lower than or equal to the respective first change threshold.

In another example, instead of relying on a threshold based approach, the classification of the luminaires <NUM> into the two or more predefined luminaire classes may comprise applying a clustering technique known in the art to assign the luminaires <NUM> into the two or more predefined luminaire classes based on the respective one or more change parameters derived therefor. In this regard, the change rate parameters applied in the classification may include respective one or more change rate parameters derived for each luminaire <NUM> under consideration and/or respective one or more value range parameters derived for each luminaire <NUM> under consideration, possibly together with respective one or more change parameters of other type derived for each luminaire <NUM> under consideration.

A clustering-based luminaire classification may comprise applying a clustering model to pre-assign the plurality of luminaires <NUM> into two or more clusters based on the respective one or more change parameters defined therefor and assigning one or more of the clusters into respective ones of the two or more predefined luminaire classes in dependence of the respective one or more change parameters derived for the luminaires pre-assigned into the respective clusters. Non-limiting examples of applicable clustering models include hierarchical clustering, centroid-based clustering, distribution-based clustering, density-based clustering, etc..

As an example, the assignment of the one or more of the clusters into respective ones of the two or more predefined luminaire classes may comprise assigning a first cluster that includes luminaires for which the change parameters derived therefor indicate relatively small change in sensor values over time (e.g. a low change rate and/or a small dynamic range) into a first predefined luminaire class and assigning a second cluster that includes luminaires for which the change parameters indicate relatively large change in sensor values over time (e.g. a high change rate and/or a large dynamic range) into a second predefined luminaire class. Herein, as described in the foregoing in an example pertaining to the threshold-based classification, the first predefined luminaire class may represent luminaires operated in an enclosed space and the second predefined luminaire class may represent luminaires operated in an open space. Consequently, each luminaire class resulting from the classification procedure may consist of respective luminaires <NUM> for which the changes in sensor values are found to be different from those assigned to other luminaire classes.

Referring back to the flowchart of <FIG>, the method <NUM> may, optionally, further comprise instructing at least one of the plurality of luminaires <NUM> assigned into one of the two or more predefined luminaire classes to assume respective predefined luminaire settings allocated for the respective one of the two or more predefined luminaire classes, as indicated in block <NUM>. The predefined luminaire settings may comprise, for example, respective luminaire-class-specific values for one or more lighting control parameters applied in the lighting control logic applied by the lighting control device <NUM> for controlling the light output from the luminaire <NUM>.

As an example, the aspect of instructing at least one of the luminaires <NUM> to apply luminaire settings in accordance with its classification into one of the two or more predefined luminaire classes may involve transmitting, via the lighting control gateway <NUM>, a command or indication in this regard to the respective one of the luminaires <NUM>-k or otherwise controlling the respective one of the luminaires <NUM>-k to apply luminaire settings according to classification carried out by the analysis means in the lighting control server <NUM>. As a non-limiting example, the luminaire <NUM>-k may have the respective luminaire settings allocated for each of the two or more luminaire classes stored therein and the luminaire <NUM>-k (e.g. the adaptation means therein) may be arranged to adopt, upon reception of the command or indication in this regard, the luminaire settings allocated for the luminaire class indicated in the command or indication received from the lighting control server <NUM> (via the lighting control gateway <NUM>).

Still referring to the flowchart of <FIG>, the method <NUM> may, optionally, further comprise grouping luminaires <NUM> assigned into at least one of the two or more predefined luminaire classes into respective one or more luminaire groups based at least on similarity of sensor values in corresponding time series of sensor values in the respective sensor data obtained for two or more luminaires <NUM> assigned into the respective one of the two or more predefined luminaire classes, as indicated in block <NUM>. The grouping of luminaires assigned into at least one of the two or more predefined luminaire classes may be applied for various purposes that pertain to controlling or fine-tuning operation of the lighting system <NUM> and/or to providing a user or maintenance personnel with information concerning mapping between the luminaires <NUM> installed in the space(s) they serve to illuminate and their positions on a floorplan of the space(s). A more detailed example concerning such mapping is provided in the following.

The method <NUM> may, optionally, further comprise providing at least one of the luminaires <NUM> with an indication of the luminaire group to which it is assigned, as indicated in block <NUM>. As an example of providing such an indication, the analysis means in the lighting control server <NUM> may be arranged to transmit, via the lighting control gateway <NUM> to a luminaire <NUM>-k, an indication comprising a group identifier of the group to which the luminaire <NUM>-k is assigned and/or identifiers of one or more other luminaires assigned to the same group with the luminaire <NUM>-k. Consequently, the adaptation means in the lighting control device <NUM>-k of the luminaire <NUM>-k may adjust the lighting control logic (applied by the lighting control means) in the lighting control device <NUM>-k of the luminaire <NUM>-k e.g. such that it follows at least some lighting control actions taken by other luminaires in the same luminaire group based on the status indications received therefrom. In an example in this regard, the lighting control logic in the luminaire <NUM>-k may be adjusted such that light output from the luminaire <NUM>-k is switched on or adjusted to the stand-by light intensity Ioff,k in response to receiving a status indication indicating another luminaire <NUM>-j assigned to the same luminaire group with the luminaire <NUM>-k having switched on its light output or having adjusted its light output to the stand-by light intensity Ioff,j, respectively.

Referring back to operations described with references to block <NUM>, the corresponding time series of sensor values in the respective sensor data obtained for two or more luminaires <NUM> is the one that represents the same environmental characteristic. As an example, the grouping may be based on the respective first time series of sensor values that represents the first environmental characteristic as a function of time in respective sensor data obtained for two or more luminaires <NUM> classified into the same one of the two or more predefined luminaire classes. In another example, the grouping may be based on the respective first time series of sensor values that represents the first environmental characteristic as a function of time and on the respective second time series of sensor values that represents the second environmental characteristic as a function of time in respective sensor data obtained for two or more luminaires <NUM> classified into the same one of the two or more predefined luminaire classes, whereas in further examples this generalizes into any number of time series of sensor values representing a respective environmental characteristic obtained for two or more luminaires <NUM> classified into the same one of the two or more predefined luminaire classes.

The grouping of luminaires in accordance with operations described with reference to block <NUM>, the grouping may comprise grouping luminaires <NUM> assigned into one of the two or more predefined luminaire classes into said respective one or more luminaire groups based at least on timing of one or more changes in the sensor values in the corresponding time series of sensor values in respective sensor data obtained for luminaires assigned into the respective one of the two or more predefined luminaire classes. As non-limiting examples in this regard, the grouping may consider one or more changes in sensor values that occur at respective predefined time instants within the analysis window (e.g. at respective predefined time delays from the beginning of the analysis window) or any changes within the analysis window that exhibit a change rate exceeding a predefined threshold.

According to an example, the timing-based grouping may consider a first time series of sensor values (that represent the first environmental characteristic) obtained for a first luminaire <NUM>-k that is assigned to a given luminaire class and a first time series of sensor values (that also represent the first environmental characteristic) obtained for a second luminaire <NUM>-j that is assigned to the given luminaire class and carrying out the one or more of the following:.

The example above considers only the respective first series of sensor values obtained for the first luminaire <NUM>-k and for the second luminaire <NUM>-j. In another example, the grouping may further consider the respective second series of sensor values obtained for the first luminaire <NUM>-k and for the second luminaire <NUM>-j. In such a scenario, the assignment of the first and second luminaires <NUM>-k, <NUM>-j into the same luminaire groups or into separate luminaire groups becomes valid only if the respective assignments carried out based on the first time series of sensor values and based on the second time series of sensor values result in similar grouping with respect the first and second luminaires <NUM>-k, <NUM>-j. In a further example, the grouping may consider any number of time series available in the respective sensor data obtained for the first and second luminaires <NUM>-k, <NUM>-j and the grouping becomes valid only if at least a predefined number (or a predefined percentage) of respective assignments carried out based on respective time series of sensor values result in similar grouping with respect the first and second luminaires <NUM>-k, <NUM>-j.

Still referring to the grouping of luminaires in accordance with operations described with reference to block <NUM>, the grouping may comprise grouping luminaires <NUM> assigned into one of the two or more predefined luminaire classes into said respective one or more luminaire groups based at least on similarity of sensor values in at one or more time instants in the corresponding time series of sensor values in respective sensor data obtained for luminaires assigned into the respective one of the two or more predefined luminaire classes. As non-limiting example in this regard, the grouping may consider one or more sensor values that occur at respective predefined time instants within the analysis window (e.g. at respective predefined time delays from the beginning of the analysis window).

According to an example, the value-based grouping may consider a first time series of sensor values (that represent the first environmental characteristic) obtained for a first luminaire <NUM>-k that is assigned to a given luminaire class and a first time series of sensor values (that also represent the first environmental characteristic) obtained for a second luminaire <NUM>-j that is assigned to the given luminaire class, deriving a difference measure based on sensor values at said one or more time instants in the first time series of sensor values obtained for said first luminaire <NUM>-k and corresponding sensor values at said one or more time instants in the first time series of sensor values obtained for said second luminaire <NUM>-j, and carrying out the one or more of the following:.

The example above considers only the respective first series of sensor values obtained for the first luminaire <NUM>-k and for the second luminaire <NUM>-j. In another example, the grouping may further consider the respective second series of sensor values obtained for the first luminaire <NUM>-k and for the second luminaire <NUM>-j and possibly also one or more further time series of sensor values obtained for the first and second luminaires <NUM>-k, <NUM>-j. Along the lines described in the foregoing in context of the timing-based groping, the grouping may become valid only if at least a predefined number (or a predefined percentage) of respective assignments carried out based on respective time series of sensor values result in similar grouping with respect the first and second luminaires <NUM>-k, <NUM>-j.

In an example, the grouping of luminaires within a luminaire class may comprise multiple aspects of similarity, e.g. the simultaneousness of timing of changes in the corresponding time series of sensor values obtained for two or more luminaires <NUM> assigned into the same luminaire class and/or the similarity of sensor values in the corresponding time series of sensor values obtained for two or more luminaires <NUM> assigned into the same luminaire class described in the foregoing. The threshold-based grouping may result in different grouping with respect to the first luminaire <NUM>-k and the second luminaire <NUM>-j when considering different aspect of similarity in the sensor values obtained therefor (e.g. the simultaneousness of timing of changes and similarity of sensor values) and/or when considering different time series of sensor values obtained therefor (e.g. the first time series and the second time series of sensor values). To account for such a scenario, e.g. the following procedure may be applied for grouping the luminaires <NUM>-k and <NUM>-j:.

In another example, instead of relying of a threshold based approach, the grouping of the luminaires <NUM> into the two or more luminaire groups may comprise applying a clustering technique known in the art to further assign the luminaires <NUM> assigned into a given luminaire class into two or more luminaire groups. Such clustering may consider respective one or more aspects of similarity derived for each luminaire assigned into the luminaire class under consideration, e.g. respective similarity of timing of changes in sensor values in the corresponding time series obtained for the luminaires under consideration, derived based on respective one or more time series of sensor values obtained for each luminaire <NUM> under consideration, and/or respective similarity of sensor values in the corresponding time series obtained for the luminaires under consideration, derived based on respective one or more time series of sensor values obtained for each luminaire <NUM> under consideration. In this regard, the similarity of timing of changes and/or the similarity of sensor values may be assessed as described in the foregoing.

A clustering-based luminaire grouping may comprise applying a clustering model to pre-assign the luminaires under consideration into two or more clusters based on the respective one or more change aspects of similarity and assigning one or more of the clusters into respective two or more luminaire groups. Non-limiting examples of applicable clustering models include the ones referred to in the foregoing, i.e. hierarchical clustering, centroid-based clustering, distribution-based clustering, density-based clustering, etc. Consequently, each luminaire group resulting from the grouping procedure may consist of luminaires <NUM> for which the changes in sensor values have been found to occur substantially simultaneously and/or for which substantially the sensor values have been obtained.

As described in the foregoing, the classification of luminaires into the two or more predefined luminaire classes and further grouping of luminaires assigned into at least one of the luminaire classes into one or more luminaire groups may be applied to facilitate mapping between the luminaires <NUM> installed in the spaces they serve to illuminate and respective spaces illustrated in a floorplan. Such mapping may be enabled, for example, via a graphical user interface (GUI) of a user device (e.g. a mobile phone, a tablet computer, a laptop computer, a desktop computer, etc.) that is coupled to the lighting control server <NUM> via the communication network. As a non-limiting example, such a mapping procedure may include the following steps:.

As an example, the mapping procedure outlined above may be applicable for defining the mapping between the luminaire units <NUM>-<NUM> to <NUM>-<NUM> (and hence the luminaires <NUM>-<NUM> to <NUM>-<NUM>) and their designated locations on the floorplan shown in the example of <FIG>. In particular, the classification and/or grouping of the luminaires <NUM>-<NUM> to <NUM>-<NUM> may result in a first luminaire group that includes the luminaires <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM>, a second luminaire group that includes the luminaire <NUM>-<NUM> and a third luminaire group that includes the luminaires <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM>. Moreover, the luminaires <NUM>-<NUM> to <NUM>-<NUM> may be ones assigned to a first predefined luminaire class that represents luminaires operated in an enclosed space and the luminaires <NUM>-<NUM> to <NUM>-<NUM> may be ones assigned to a second predefined luminaire class that represents luminaires operated in an enclosed space. Consequently, the classification and grouping of the luminaires <NUM> may provide information that conveniently enables the mapping between the plurality of luminaires <NUM> and the designated luminaire locations on the floorplan.

In many scenarios mapping the plurality of luminaires <NUM> to respective spaces of the floorplan already provides a sufficient mapping accuracy. In case further mapping accuracy is necessary or desirable, the mapping between the luminaires <NUM> and the respective spaces of the floorplan derived based on the luminaire classification and luminaire grouping that relies on the history data comprising the sensor indications captured at the plurality of luminaires <NUM> may be further elaborated based further information pertaining to at least some of the luminaires <NUM>, which may enable mapping between one or more luminaires <NUM> installed in a given space and their locations within the given space. Such further information may be displayed as part of the luminaire information in the mapping procedure outlined above to facilitate user-input-based mapping. Non-limiting examples of such elaborated mapping include the following.

The mapping between the luminaires <NUM> of the lighting arrangement <NUM> and the spaces they serve to illuminate may enable the lighting control server <NUM> to at least partially control HVAC (heating, ventilation and air conditioning) functions available in said spaces (e.g. via an application programmable interface (API) provided by the HVAC system) in dependence of the sensor values obtained for the luminaires <NUM> mapped to said spaces or to provide an underlying HVAC system with information that enables improved control of HVAC functions available in said spaces.

As a non-limiting example in this regard, the sensor indications provided from the plurality of luminaires <NUM> (via the lighting control gateway <NUM>) to the lighting control server <NUM> further comprises respective time series of occupancy indications obtained or derived at the respective one of the luminaires <NUM>. Consequently, the respective sensor data obtained (by the analysis means) at the lighting control server <NUM> for a given luminaire <NUM>-k may further include a respective time series of occupancy indications pertaining to the given luminaire <NUM>-k. Further assuming the respective sensor data for the given luminaire <NUM>-k to include a respective time series that represents the CO<NUM> level as a function of time (i.e. a time series of CO<NUM> levels), the analysis means may be arranged to derive, based on the time series of occupancy indications and the time series of CO<NUM> levels obtained for the luminaire <NUM>-k, a conversion function that is descriptive of the relationship between the number of occupancy indications per time unit and an increase rate of CO<NUM> level during the time unit.

As an example, such conversion function is directly applicable for estimating the expected increase in the CO<NUM> level based on the time series of occupancy indications obtained for the luminaire <NUM>-k and it can be also expected to enable deriving a reliable estimate of the expected increase in the CO<NUM> level based on respective time series of occupancy indications obtained for any luminaire that is assigned in the same luminaire group with the luminaire <NUM>-k. Consequently, e.g. the lighting control server <NUM> may be arranged to control ventilation or air conditioning in the space for which the luminaire <NUM>-k (or any other luminaire <NUM> assigned to the same luminaire group) serves to illuminate based on the respective time series of occupancy indications received from the luminaire <NUM>-k and/or from one or more other luminaires assigned in the same luminaire group with the luminaire <NUM>-k and/or to issue an indication concerning expected increase in the CO<NUM> level in said space (which, for example in a scenario where said space is a meeting room, may result in scheduling a break to avoid participant fatigue due to high CO<NUM> level).

In another example, the conversion function may be applied with a scheduling application that is employed to handle reservations to a space that serves as a meeting room or as a corresponding space: experimental data may be employed to derive a mapping between the number of person in a space and the number of occupancy indications per time unit arising from said space. Consequently, when making a reservation to said space, the mapping function may be applied to convert the expected number of participants into the corresponding number of occupancy indications per time unit, which in turn may be further converted by the conversion function into the expected increase in the CO<NUM> level. With this information, the scheduling application is able to estimate the time period after which the CO<NUM> level in said space reaches a predefined maximum CO<NUM> level, which time period may be indicated as the recommended maximum duration of a meeting in said space with the indicated number of participants.

In yet another example, the conversion function may be applied in the opposite manner, i.e. to estimate the number of occupancy indications based on the observed increase in the CO<NUM> level, which may be derived based on the respective time series of CO<NUM> levels obtained for the luminaire <NUM>-k and/or for one or more other luminaires <NUM> assigned in the same luminaire group with the luminaire <NUM>-k. In this regard, the estimated number of occupancy indications (per time unit) may be further converted into the estimated number of persons in the space the luminaires <NUM>-k and/or one or more other luminaires <NUM> assigned in the same luminaire group with the luminaire <NUM>-k serve to illuminate. Consequently, in case such procedure of estimating the number of persons in said space indicates a change in (e.g. long-term average of) the estimated number of persons in said space, this may serve as indication of changes having occurred in one or more spaces the lighting arrangement <NUM> serves to illuminate and/or as indication of a malfunction in one or more luminaire units <NUM> or luminaires <NUM> of the lighting arrangement <NUM>.

The examples described in the foregoing assumed the lighting arrangement <NUM> to include the plurality of lighting units <NUM>-k of the kind illustrated by the block diagram of <FIG>. In a variation of the lighting arrangement <NUM>, some of the lighting units may comprise a lighting unit <NUM>-k', illustrated by a block diagram of <FIG>. The lighting unit <NUM>-k' comprises consists of the luminaire <NUM>-k that comprises the lighting control device <NUM>-k and the at least one light source <NUM>-k. Hence, the difference to the lighting unit <NUM>-k is that the lighting unit <NUM>-k' does not include a dedicated sensor unit but receives the sensor signals from a sensor unit of another luminaire unit, e.g. from the sensor unit <NUM>-j of the luminaire unit <NUM>-j.

In another variation of the lighting arrangement <NUM>, the plurality of the luminaires <NUM> may be coupled to the lighting control server <NUM> via a plurality of (i.e. two or more) lighting control gateways <NUM>. In such a variation of the lighting arrangement <NUM>, each lighting control gateway <NUM> receives respective sensor indication messages from one or more luminaires <NUM> coupled thereto, stores the sensor indications received in these sensor indication messages as respective composite history data in a memory provided therein, and provides the sensor indications stored in the respective composite history data to the lighting control server <NUM> for (storage and) analysis therein.

In yet another variation of the lighting arrangement <NUM>, the dedicated lighting control server <NUM> may be omitted and the corresponding functionality may be provided by the lighting control gateway <NUM>. In such a variation of the lighting arrangement <NUM>, the operations described with references to the analysis means in the lighting control server <NUM> may be carried out by an analysis means provided in the lighting control gateway <NUM> instead, mutatis mutandis. In other words, in such a variation of the lighting arrangement <NUM> the lighting control gateway <NUM> at least conceptually operates (also) as the lighting control server <NUM>.

In yet another variation of the lighting arrangement <NUM>, the both the dedicated lighting control server <NUM> and the lighting control gateway(s) <NUM> may be omitted and the corresponding functionality may be provided by one of the luminaire units <NUM>, <NUM>', e.g. by the lighting control device <NUM>-kof the luminaire unit <NUM>-k or <NUM>-k'. In such a variation of the lighting arrangement <NUM>, the operations described with references to the analysis means in the lighting control server <NUM> may be carried out by an analysis means provided in the lighting control device <NUM>-k instead, mutatis mutandis. In other words, in such a variation of the lighting arrangement <NUM> the lighting control device <NUM>-k at least conceptually operates (also) as the lighting control server <NUM>.

<FIG> illustrates a block diagram of some components of an exemplifying apparatus <NUM>. The apparatus <NUM> may comprise further components, elements or portions that are not depicted in <FIG>. The apparatus <NUM> may be referred to as a computing apparatus and it may be employed e.g. in implementing at least some of the operations, procedures and/or functions described in the foregoing in context of the analysis means.

The apparatus <NUM> comprises a processor <NUM> and a memory <NUM> for storing data and computer program code <NUM>. The memory <NUM> and a portion of the computer program code <NUM> stored therein may be further arranged to, with the processor <NUM>, to implement at least some of the operations, procedures and/or functions described in the foregoing in context of the analysis means.

The apparatus <NUM> comprises a communication portion <NUM> for communication with other devices. The communication portion <NUM> comprises at least one communication apparatus that enables wired or wireless communication with other apparatuses. A communication apparatus of the communication portion <NUM> may also be referred to as a respective communication means.

The apparatus <NUM> may, optionally, further comprise one or more user I/O (input/output) components <NUM> that may be arranged, possibly together with the processor <NUM> and a portion of the computer program code <NUM>, to provide a user interface for receiving input from a user of the apparatus <NUM> and/or providing output to the user of the apparatus <NUM> to control at least some aspects of operation of the lighting control device <NUM>-k implemented by the apparatus <NUM>. The user I/O components <NUM> may comprise hardware components such as a display, a touchscreen, a touchpad, an arrangement of one or more keys or buttons, etc. The user I/O components <NUM> may be also referred to as peripherals. The processor <NUM> may be arranged to control operation of the apparatus <NUM> e.g. in accordance with a portion of the computer program code <NUM> and possibly further in accordance with the user input received via the user I/O components <NUM> and/or in accordance with information received via the communication portion <NUM>.

Although the processor <NUM> is depicted as a single component, it may be implemented as one or more separate processing components. Similarly, although the memory <NUM> is depicted as a single component, it may be implemented as one or more separate components, some or all of which may be integrated/removable and/or may provide permanent / semi-permanent/ dynamic/cached storage.

The computer program code <NUM> stored in the memory <NUM>, may comprise computer-executable instructions that control one or more aspects of operation of the apparatus <NUM> when loaded into the processor <NUM>. As an example, the computer-executable instructions may be provided as one or more sequences of one or more instructions. The processor <NUM> is able to load and execute the computer program code <NUM> by reading the one or more sequences of one or more instructions included therein from the memory <NUM>. The one or more sequences of one or more instructions may be configured to, when executed by the processor <NUM>, cause the apparatus <NUM> to carry out at least some of the operations, procedures and/or functions described in the foregoing in context of the analysis means. Hence, the apparatus <NUM> may comprise at least one processor <NUM> and at least one memory <NUM> including the computer program code <NUM> for one or more programs, the at least one memory <NUM> and the computer program code <NUM> configured to, with the at least one processor <NUM>, cause the apparatus <NUM> to perform at least some of the operations, procedures and/or functions described in the foregoing in context of the analysis means.

The computer programs stored in the memory <NUM> may be provided e.g. as a respective computer program product comprising at least one computer-readable non-transitory medium having the computer program code <NUM> stored thereon, the computer program code, when executed by the apparatus <NUM>, causes the apparatus <NUM> at least to perform at least some of the operations, procedures and/or functions described in the foregoing in context of the analysis means. The computer-readable non-transitory medium may comprise a memory device or a record medium such as a CD-ROM, a DVD, a Blu-ray disc or another article of manufacture that tangibly embodies the computer program. As another example, the computer program may be provided as a signal configured to reliably transfer the computer program. Reference(s) to a processor should not be understood to encompass only programmable processors, but also dedicated circuits such as field-programmable gate arrays (FPGA), application specific circuits (ASIC), signal processors, etc. Features described in the preceding description may be used in combinations other than the combinations explicitly described.

Claim 1:
A method (<NUM>) for classifying a plurality of luminaires (<NUM>) based on respective sensor data captured at respective locations of the plurality of luminaires (<NUM>) that are arranged for illuminating a plurality of spaces, the method (<NUM>) comprising:
obtaining (<NUM>) the respective sensor data for the plurality of luminaires (<NUM>), the respective sensor data for each luminaire (<NUM>) comprising respective one or more time series of sensor values that each represent a respective environmental characteristic at the respective location of said plurality of spaces as a function of time for a respective one of the plurality of luminaires (<NUM>),
assigning (<NUM>) at least one of the plurality of luminaires (<NUM>) into one of two or more predefined luminaire classes based on variation of the sensor values in the respective one or more time series of sensor values in the sensor data obtained for the respective luminaire (<NUM>)
characterized in that said assigning (<NUM>) comprises
deriving, for each of the plurality of luminaires (<NUM>), based on at least one time series of sensor values included in the sensor data obtained for the respective luminaire (<NUM>-k), a respective change rate parameter that is descriptive of a change rate of sensor values in said at least one time series of sensor values, and
assigning at least one of the plurality of luminaires (<NUM>) into one of said two or more predefined luminaire classes based on the change rate parameter derived for the respective one of the plurality of luminaires (<NUM>),
wherein said one or more time series of sensor values included in the sensor data obtained from the respective luminaire (<NUM>-k) represents at least one of the following environmental characteristics: carbon dioxide level, respective volatile organic compound, VOC, level for one or more VOCs, humidity, air pressure.