WO2003067933A1

WO2003067933A1 - Smart led traffic lamp

Info

Publication number: WO2003067933A1
Application number: PCT/TR2003/000007
Authority: WO
Inventors: Umut Aydin; Ahsen GÖNÜLLÜ
Original assignee: Ortana Elektronik Yazilim Taahhut Sanayi Ve Ticaret Ltd. Sti.
Priority date: 2002-02-08
Filing date: 2003-02-07
Publication date: 2003-08-14
Also published as: EP1514454A1; AU2003219642A1

Abstract

The smart LED-traffic lamp combines the operation functions of a traffic signaler, an active synchronized winker, an active synchronized flasher and a reverse timer, in one device, without connection to a control device. It is also possible to operate it by connecting to a control device, when required. Use functions of the invention are programmed onto a microprocessor unit. Functions are selected by a multi-stage switch on the device and thus, the device is programmed according to the use purpose. The device takes the required power from the mains of 220 VAC, 50 Hz. However, it may be operated with 110 VAC, 60 Hz as well. In addition, it may be operated in three-phase supply, with a very short synchronization interval, not visible by human eye. This invention is operated by connecting to an intersection control device through one power line and one data line. It receives the main supply from the power line. Lighting power adjustment and function selection are performed through the data line, Traffic signal lights developed with this invention may be operated by connecting in parallel to one power line and one data line.

Description

SPECIFICATION Smart LED Traffic Lamp

This invention is a smart LED traffic lamp combining the operation functions of a traffic signaler, an active synchronized winker, an active synchronized flasher and a reverse timer.

Traffic lights are used through out the world to regulate vehicle and pedestrian traffic. According to a standard accepted all over the world, red, yellow and green lights have the same meaning in all the countries. Also a standard has been established for the sizes of the lamps, which are compulsory to have a diameter of 100 mm, 200 mm or 300 mm, according to the density of the intersection or passageway where they are used.

Glow or halogen bulbs and LEDs (light Emitting Diode) are used in traffic lights all over the world. Today, glow or halogen bulbs are replaced by LED bulbs, although they are still used broadly. LED traffic lights become more common day by day, because they consume less power, they have a longer service life, they are more durable and they require less maintenance.

Glow or halogen-bulb traffic lamps consume 75-100 w/hour, depending the size of the lamp. Halogen lamps consume about 60 w/hour. LED traffic lamps can provide the same lighting power by consuming 5-15 w/hour, depending on the size of the lamp. Furthermore, glow bulbs are more sensitive to temperature changes. They may blow out in instant temperature changes and may cause danger for the traffic. This increases maintenance costs, although defective lamps are replaced quickly. LED lamps are not affected by temperature changes. An instant temperature change of 50 °C is required for a LED lamp to blow out. Due to such properties, LED lamps have a longer service life. Average lighting time for a LED lamp is 100.000 hours. At the end of this period, lighting power decreases to half and the service life of the lamp is supposed to run out. Traffic lamps used in traffic signalization are used as traffic signalers, multi-winkers or multi - flashers.

The existing traffic signalers are controlled by a central unity (intersection control device). Intersection control devices are programmed during their installations to determine the lighting time and order of every signaler at that intersection.

Flashing lamps are used in multi-groups and they suddenly light and go off successively. The lighting time of a flasher is a small portion of its flashing time (1). Flashers are used in dangerous sections of roads, in indicating constructions in progress or in indicating the border of road under limited visibility conditions such as fog, snow, etc. they from a lighted line along the edge of road and they ensure that the drivers recognize the border of road. Flashers in a multi - group light successively in sudden flashes. The first flasher lights after the last flasher goes off. This continues periodically (2).

Winkers are warning lamps, lighting for a longer time. The lighting time of a winker is almost half of its period. Winkers used in a group light and go off successively. However, different from flasher, two successive winkers light together in some portion of their lighting periods (3).

In recent years, reverse timers have been started to be used with signalers. Reverse timers showing the duration of the red or green light in seconds, in the same color, become more common increasingly. Reverse timers inform drivers and pedestrians waiting at the light and they ensure that they are more careful and they do not commit a signal violation.

Traffic lamps are used as signalers by connecting to a standard intersection control device, as winkers by connecting to a multi-group winker control device and as flashers by connecting to a multi-group flasher control device. Reverse timers count the time reversly by connecting to a standard intersection control device. That is, a traffic lamp can not be operated as a signaler, a winker in group or a flasher in group, unless it is connected to the relevant intersection control device. A signaler lamp may be operated as an independent winker by an intersection control device, but it can not be operated as a group - winker unless it is connected to a winker control device also, as the existing LED signalers receive information only about the lighting period from a winker control device, it is imposible to operate a signaler lamps as a reverse timer sowing figures.

The smart LED traffic lamp combines all these operation modes in one device, without need for an intersection control device or an external control device due to such a property it provides fast and inexpensive solutions. To any place where the traffic is required to be regulated in a short time. Furthermore, the required traffic signalization may be established by use of existing cable sub-structure, in those sections of roads where any control device is not available. In doing this, there is no need for those complicated cabling systems requiring time and costing more. One device is capable of performing multi-functions. Thus, smart LED traffic lamps may be used as signalers, winkers, flashers and reverse timers, when an urgent traffic signalization is required on a road. Another superiority of this invention is that, this lamp may perform both instant lighting / going off and smooth lighting / going off alternatives, when it is used as a winker or flasher. Furthermore this invention may be operated by connecting to an intersection control device and thus, it may be used in intersection signalization arrangements controlled by an intersection control device.

The drawings used to explain the purposes of the invention are at enclosure and are as follows :

Figure 1 : Lighting - time graphic of a six-group flasher and showing successive lighting of flashers ordered in six - groups.

Figure 2 : Lighting - time graphic of three - group flashers and showing simultaneous lighting at time intervals. Figure 3 : a. Voltage - time graphic of alternative input tension. b. Pulse-time graphic sent by the zero breakdown voltage detector to the microprocessor, during zero breakdown tension. Figure 4 : a. Voltage - time graphic of alternative input tension. b. Pulse-time graphic sent by the zero breakdown voltage detector to the microprocessor, during zero breakdown tension. c. Lighting - time graphic of the 1st LED traffic lamp in a three - group with a period of 12 triggers, with a lighting period of 6 triggers, with an offset of 0 according to zero breakdown voltage pulses. d. Lighting - time graphic of the 1st LED traffic lamp in a three - group with a period of 12 triggers, with a lighting period of 6 triggers, with an offset of 4 according to zero breakdown voltage pulses. e. Lighting - time graphic of the 1st LED traffic lamp in a three - group with a period of 12 triggers, with a lighting period of 6 triggers, with an offset of 8 according to zero breakdown voltage pulses.

Figure 5 : a. Voltage - time graphic of alternative input tension. b. Pulse-time graphic sent by the zero breakdown voltage detector to the microprocessor, during zero breakdown tension.

^• c. Smooth lighting / going of lighting - time graphic of a smart LED traffic lamp with a lighting period of 30 triggers, with an unspecified period and offset, according to zero breakdown voltage pulses. d. Smooth lighting / going off current - time graphic of smart LED traffic lamp with a lighting period of 30 triggers according to zero breakdown voltage pulses.

Figure 6 : A sample of LED array and display of figures in the indicator of the invention.

Figure 7 : Side internal view of the invention. Figure 8 : Block diagram of the units in the smart LED traffic lamp

Figure 9 : Zero breakdown voltage detector circuit diagram

Figure 10. a. Voltage - time graphic of the alternative input tension, when mains tension is sent to the smart LED traffic lamp, without change b. Pulse - time graphic sent by the zero breakdown voltage detector to the microprocessor, when mains tension is sent to the smart LED traffic lamp, without change. c. Positive cycle output of the zero breakdown voltage detector, when mains tension is sent to the smart LED traffic lamp, without change. d. Negative cycle output of the zero breakdown voltage detector, when mains tension is sent to the smart LED traffic lamp, without change. Figure 11. a. Voltage - time graphic of the alternative input tension, when only positive half of the mains tension are sent to the smart LED traffic lamp. b. Current - time graphic sent by the zero breakdown voltage detector to the microprocessor, when only positive half periods of the mains tension are sent to the- smart LED traffic lamp. c. Positive cycle output of the zero breakdown voltage detector when only positive half periods of the mains tension are sent to the smart LED traffic lamp. d. Negative cycle output of the zero breakdown voltage detector when only positive half periods of the mains tension are sent to the smart LED traffic lamp.

Figure 12. a. Parallel connection of the lamps to one power supply line and one data line at an intersection b. Connection of standard traffic signaler lamps to an intersection control device at an intersection.

Drawings are numbered as follows :

1. Lighting period of a flasher

2. Lighting of flashers successively 3. Lighting period of a winker

4. Pulses sent by the zero breakdown voltage detector to the microprocessor

5. Use of zero breakdown voltage pulses as time determiners

6. Smooth lighting and going off

7. creating figures on the indicator 8. electronic circuit

9. Indicator consisting of LEDs

10. Socket Power cable coming to the invention (lamp) Data cable coming to the invention (lamp) Zero breakdown voltage detector Microprocessor LED drive circuits Memory circuits Direct current power supply Communication circuits Zero brealcdown voltage output of the zero brealcdown voltage detector Positive cycle output of the zero brealcdown voltage detector Negative cycle output of the zero brealcdown voltage detector Pulse - time graphic sent by the zero brealcdown voltage detector to the microprocessor, when mains tension is sent to the invention, without change. Positive cycle output signal of the zero breakdown voltage detector, when mains tension is sent to the invention, without change. Negative cycle output signal of the zero brealcdown voltage detector, when mains tension is sent to the invention, without change. Voltage - time graphic of the alternative input tension, when only positive half periods of the mains tension are sent to the invention. Current - time graphic sent by the zero brealcdown voltage detector to the processor, when only positive half periods of the mains tension are sent to the invention. Positive cycle output signal of the zero brealcdown voltage detector, when only positive half periods of the mains tension are sent to the invention. Negative cycle output signal of the zero brealcdown voltage detector, when only positive half periods of the mains tension are sent to the invention. Connection of standard traffic signaler lamps to an intersection control device at an intersection. An intersection control device, which has one switching circuit. An intersection control device, which has multi - switching circuits. Switching circuit section of an intersection control device, which has one switching circuit. 33 Switching circuit section of an intersection control device, which has multi- switching circuits.

The sections and operation ways of the smart LED traffic lamp is explained below.

The invention receives all the required power from the main power supply. It operates with 220 VAC, 50 Hz, as well as 110 VAC, 60 Hz in some countries as the United States. The functions of the smart LED traffic lamp are performed by an indicator of LEDs (9) used as the radiation element and a microprocessor - electronic circuit (8). The electronic circuit is placed in front of the invention so as to be seen by the user.

Electronic circuit elements in the invention operate with direct current (DC). The LEDs in the indicator are also driven and lighted by direct current. For this purpose, there is a power supply in the invention, transforming the main tension to direct current. Direct current voltage obtained from DC power supply outputs are distributed to both electronic circuit elements and LED groups in the indicator, by connecting to them.

The main tension is connected to both the input of the DC power supply and the input of the zero brealcdown voltage detector. The outputs of the detector are connected to a microprocessor unit. The zero brealcdown voltage detector follows the sinusoidal curve of the alternative tension and transmits a triggering signal to the invention are programmed in the microprocessor unit. The functions and the operation mode of the invention are selected by a multi-stage switch connected to the microprocessor.

The microprocessor recognizes the use function of the invention, based on the data received from the switch and transmits the proper current data to the LED drive integrated circuits. LED drivers adjust the current to the LEDs in the indicator, based on the-current-time data received from the microprocessor and operate the lamp according to the selected function. The microprocessor performs the operation of the lamp as a signaler, as a winker or as a flasher, by sending current-time data, during the period determined for each operation mode in the program. Current sending time is determined by the triggers of the zero breakdown voltage detector. That is, triggering by the zero breakdown voltage detector are used as time determiners (5). The invention recognizes the required number of trigger pulses to be received during its total period, the required time of being lighted during how many trigger pulses and the amount of offset of the start of lighting according to the start of period and performs its functions according to such trigger pulses. For example, a smart LED traffic lamp to be lighted during

0.5 second, with on offset of 0.25 second in a period of one second stays dark during a period of 25 triggering pulses, stays lighted during the following 50 triggering period, goes off during 50 triggering period and then stays lighted again during 50 triggering period and continues to light and to go off in this way, when it is first energyzed by a 50 Hz main tension.

The fact that the invention determines separately the lighting period, the total period, the offset time during the period allows to create indefinite different combinations of flasher and winkers. Such combinations may be made by the multi-stage switch easily, according to the requirement, at the stage of installation.

All the groups should be energyzed at the same time to operate in a correct and synchronized manner, when the device is programmed in multi-groups. The device can be operated with three-phase main power supply, without problems. As the zero breakdown voltage delay among the phases is a very short period of time (3.3 miliseconds for 50 Hz, 2.78 miliseconds for 60 Hz), a synchronization delay, invisible by human eye will occur.

When the device is connected to an intersection control device, in order to operate as a standard traffic signaler, the function is selected by the switch on it. In this case, the device lights when power comes from the intersection control device and goes off when power is cut. That is, the lighting and going off periods of the invention are completely determined by the intersection control device.

The invention performs instant lighting/going off and smooth lighting/going off functions as well, by selecting its switch. The operation of the smart LED traffic lamp in the functions of instant lighting/going off and smooth lighting/going off is as follows : If the invention is programmed to operate in the instant lighting/going off function, the microprocessor will send a command to the LED driver to increase the current from zero to its nominal value. In the smooth lighting/going off function, current data are sent to the LED driver by PWM method (Pulse Width Modulation), spread into time. The drive current of the LEDs is increased gradually to its nominal value to light the LEDs smoothly and in the same way, the drive current of the LEDs is decreased gradually to zero to turn off the LEDs smoothly (6). The current is decreased in the PWM Method as follows : 100% PWM shows that the current is in its nominal value continuously. 50% PWM shows that the current is in its nominal value during the half of the period between two trigger pulses and in zero value during the other half. In the same way, 25% PWM shows that the current is in its nominal value during 25% of the period between two pulses and in zero value during the remaining period. Smooth going off in a smart LED traffic lamp is performed by decreasing the PWM value to the half o its previous value, in each zero breakdown voltage trigger.

The smart LED traffic lamp performs reverse counting on its indicator, at the same time, when it operates as a signaler. The existing reverse timers are connected to the signalers as a separate lamp. The smart LED traffic lamp performs signaling and showing lighting time simultaneously.

The performance of signaling and showing lighting time of the invention at the same time is effected as follows : The LEDs in the indicator are placed so as to display 7- segment figures (7). The LEDs are darkened and seven-segment figures are created in the indicator of all the designs, although the LED array changes according to the size of lamp and density of LEDs. When the invention is programmed as a reverse timer signaler, the microprocessor darkens those LEDs, within the segments of the figures to be displayed (not sending current) during reverse counting. Thus, seven- segment figures are created in the indicator (7).

The superiority of this intention is that it can show seconds in high accuracy. The existing reverse timers count the lighting period of the signaler lamp to which they are connected, by the frequency of a crystal in their structure and record it in their memory. They display the previous period recorded in their memory in the LED indicator, when the lamp lights again. They reverse-count this period by use of the frequency of the built-in crystal and they learn the period when the lamp stays lighted, by use of the frequency of the crystal. That is, they count the lighting time in one period and reverse - count the time measured in the previous period. They perform counting process by use of the frequency of the crystal as a timer. However, the tolerance values of such crystal materials change depending on manufacturers. In addition, tolerance values of crystal materials are affected by changes in temperature. This may result in incorrect display of the counted time. Especially, if the tolerance values of the crystals of the reverse timers used at the same intersection are different, such reverse timers may display different readings in seconds and this may threaten the safety at that intersection.

The smart LED traffic lamp that reverse-counts the time of lighting, while signaling receives the time data from the zero brealcdown voltage detector's trigger pulses. When it is energyzed, it signals and records the lighting time in its memory by counting the pulses from the zero brealcdown voltage detector and by converting them into seconds at the frequency of the main power. When it is re-energyzed in the following period, it darkens the LEDs within the figure and starts to reverse- counting, so as to display the previously recorded period of time. It arranges the change time of seconds by counting the pulses from the zero brealcdown voltage detector. During this period of lighting, it records the number of zero brealcdown voltage pulses and learns the period which it would reverse-count in the next period.

That is, it lights as a signaler in one period and reverse-counts the previous period of time on its indicator. As the zero brealcdown voltage of the main tension is taken as a time determiner, the smart LED traffic lamp which functions as a reverse timer while it signals as well performs a reverse counting process not affected by temperature changes. More over, as all the reverse timers are fed by the main tension at an intersection, the possibility to show different second readings will be eliminated.

A socket-version (10) and a screw - version are available for the invention to operate in all kinds of systems easily. The socket - version enables the invention to be installed to the existing systems quickly (The bulb is taken out from the lamp and the socket - system is installed). A multi-secrew version, very durable and reliable, is available for new signalization systems.

The invention is connected to an intersection control device through a power supply cable (11) and a data line (12). Power cable (11) provides the invention with the main power. The data line (12) is used for remote distances.

The invention gives a highly bright light by means of LEDs. However, the highly bright light, preferred during daytime to obtain net visibility may distrub drivers at night. In those countries located near the Equator, which receive the bright sunlight during a long time in the year, it is impossible to use those LED systems with a lower lighting power in a vital application such as traffic signalization.

By use of this invention, the lighting power of traffic signaler lamps may be adjusted to be high in the daytime and to be low at night or under cloudy weather conditions. During operation in its normal lighting power, the alternative main tension is sent to the invention, without change. In order to reduce the lighting power of the invention, only positive cycles of the main tension are sent. This is performed by switching circuits located in an intersection control device. The zero brealcdown voltage detector (13) in the intention generates a pulse (22) in the zero brealcdown voltage output (19), when the supply tension becomes zero. The zero brealcdown voltage detector has to more outputs : positive cycle output (20) and negative cycle output (21). The detector generates positive cycle output signals (23) and negative cycle output signals (24) symmetrically, when the main tension is sent to the invention, without change. However, the zero brealcdown voltage detector (13) produces zero value in the zero brealcdown voltage output (19) during a positive signal, when only positive values of the main tension are sent (25) to the invention and

However, the zero breakdown voltage detector (13) produces zero value during a positive signal and an output signal with a constant value (26) when signals are not sent, in the zero brealcdown voltage output (19), when only positive values of the main tension are sent (25) to the invention. In this case, the positive cycle output (37) shall generate an output of zero during the period when no signal is sent, while it takes a constant value during the period of positive voltage. The voltage, mentioned as a constant value is the DC voltage output value of the power supply (17) used in the invention. DC supply voltage value in electronic circuit elements is taken 1 in logic voltage. The negative cycle output will generate a continuous zero output signal (28), because the tension never becomes negative. The outputs of the zero brealcdown voltage detector are connected to the microprocessor unit (14) within the invention. When the microprocessor (14) receives continuous zero signals from the negative cycle output of the detector, it will recognize the requirement to reduce the lighting power and make the LED drive circuits (15) send less current to the LED. Indicator (9). Lighting power is reduced by sending lower current to the

LEDs in the indicator (9) of the invention.

One of the superiorities of the invention is that many smart LED traffic lamps may be operated by connecting to one power supply (11) and data line (12).

Today, all the traffic signaler lamps are operated by connecting them to an intersection control device belonging to that intersection. Each signaler lamp is connected to the intersection control device with a separate power supply cable. An intersection control device arranges to turn-on and turn off the lamps by sending and ceasing power to the lamps through each cable. An intersection control device is quite expensive and large, because it contains a switching circuit (33) for every lamp connected to it. In addition, cabling, labor and sub-structure costs are high, because every signaler lamp is required to be connected by a separate power supply cable (29) to the intersection control device.

The smart LED traffic lamps located at an intersection may be operated by connecting them in parallel to one power supply line (11) coming from an intersection control device. That is, the power supply to all the lamps from an intersection control device are not switched, but transmitted uninterruptedly. All the lamps are connected in parallel to the data line (12) coming from an intersection control device. Lamps light and go off according to the data coming from the data line (8). The microprocessor (14) within the invention sends data to the LED drive circuits (15), turn on or turn off the LEDs according to the data coming from the microprocessor (14). The smart LED traffic lamps are programmed by multi-stage switch on them, according to the place where they are installed at an intersection and addressing data may be arranged. Thus, they can recognize the data from the data line (12) to be on or to be off. One of the superiorities of the invention is that, a smart LED traffic lamp, previously installed at a place at an intersection may be later installed in place of another lamp in the same color, by changing its function by means of the switch on it. In addition, as the communication through the data line is duplex, an intersection control device is able to know about any failure in the lamp and notice the operator or maintenance personnel.

Another superiority of the intention is that the lighting power may also be adjusted by the data transmitted through the data line and that both day and night lighting levels may be controlled. The data about arranging the lighting power is transmitted to the microprocessor through the data line and thus lighting power is adjusted, even if the supply tension coming to the invention through the power cable is not changed. In addition, lighting power may be replaced with many alternative values by the data transmitted through the data line and thus, the device does not depend only on the limitation to the night/day lighting value. Thanks to this property, one smart LED traffic lamp is able to provide different lighting power requirements in different countries. As many traffic lamps are fed by one power and data line, it provides great savings in cable costs. In addition, the cost and dimensions of an intersection control device decrease, because switching circuits are not used.

Another property of the invention is that it is capable of operating with a low DC supply voltage, as it is connected to an intersection control line with a power line together with data line. That is, a low DC voltage is sent through the power line connected to an intersection control device, instead of the alternative main tension. As the LEDs, operating with a DC voltage are used instead of lamps operating with an alternative voltage, there is no need for the high main voltage, because the invention is controlled through the data line.

A low value of DC voltage is sent from an intersection device to the invention and thus, the current required for the operation of the electronic circuits and LEDs is provided. Such a low DC voltage may be transmitted through the power line to the lamps by use of a simple power supply in an intersection control device. Thus, the power line carries a low value voltage. This protects human life in accidents and lightning strokes, because of low voltage and low current rate electricity leakage.

The operation mode of the invention is selected by a multi-stage switch from among may operation modes. Another important property of the invention is that the operation mode may be selected from a remote control device such as an intersection control unit, as well as from the multi-stage switch, manually. The invention has also a memory circuit (16). The memory circuit is able to retain the data stored, even in electricity cuts. All the operational functions of the invention are recorded in the memory. The operation function of the device is selected by sending data to the memory (16) from communication circuits (18) through the data line. This property is used in those applications having so may operation functions, for which the multistage switch may not be sufficient. Especially. The operation function of the device may be adjusted by sending data through the data line, in those groups of many winkers and flashers.

Claims

I) It is a LED-traffϊc signal lamp, consisting of an indicator of LEDs (9). A microprocessor electronic circuit (8) and a multi-stage switch. 2) It is a LED-traffϊc signal lamp, functioning as a standard traffic signaler, multi- winker (3), a multi-flasher (2) and a reverse timer (7).

3) Its multi-stage switch is capable of selecting the use purpose from among the operation modes.

4) It is the lamp mentioned in claim - 1, whose multi-stage switch is capable of switching to the multi-winker (3), multi - flasher (2) and reverse timer (7) operation modes.

5) It is the lamp mentioned in claim - 1, is capable of lighting - going off smoothly and flashing - going off instantly at the same time.

6) It is the lamp mentioned in claim - 1 , is capable of operating as a winker in a multi - group order or as a flasher in a multi - group order synchronously, without connection to a central control device.

7) It is the lamp mentioned in claim - 1, is capable of operating by use of zero brealcdown voltage, in case that it is used as a reverse timer traffic signaler.

8) It is a smart LED - traffic signal lamp, mentioned in claim -1 , having a lighting power changeable according to the signal coming from the power line (1 1).

9) It is a smart LED - traffic signal lamp, mentioned in claim -1, capable of operating by connecting to an intersection control device without switching circuits.

10) It is smart LED - traffic signal lamp, mentioned in claim -1, capable of being connected in many in number to one power line (11) coming from an intersection control device and to one data line (12).

I I) It is a smart LED - traffic signal lamp, mentioned in claim -1, effecting duplex data transmission over its data line (12) and whose operation may be checked from the data line (12).

12) It is a smart LED - traffic signal lamp, mentioned in claim -1, whose lighting power may be changed by the data coming from the data line (12), in multi - alternatives.

16 13) It is a smart LED - traffic signal lamp mentioned in claim -1, capable of recording and saving the data from the data line (12), in a permanent memory unit (16).

14) It is a smart LED traffic lamp, mentioned in claim -1, capable of operating with a low DC voltage, because, it is connected to an intersection control device through a data line.

It is a smart LED - traffic signal lamp, mentioned in claim -1, whose operation function may be selected by the commands sent over the data line

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