Toggle navigation
Publications
Profiles
Research Groups
Indexes
Help and information
Eesti keeles
Intranet
Publications
Profiles
Research Groups
Indexes
Help and information
Eesti keeles
Intranet
Databases
Publications
Searching
My bookmarks
0
reactive power control (keyword)
All fields
Source search
Author search
Subject term search
Title search
starts with
containes
exact match
All fields
Source search
Author search
Subject term search
Title search
starts with
containes
exact match
—
All fields
Source search
Author search
Subject term search
Title search
starts with
containes
exact match
—
All fields
Source search
Author search
Subject term search
Title search
starts with
containes
exact match
—
All fields
Source search
Author search
Subject term search
Title search
starts with
containes
exact match
—
Add criteria
Advanced search
filter
Clear
×
types of item
book
..
journal article
..
newspaper article
..
book article
..
dissertation
..
Open Access
..
Scientific publications
..
year
year of publication
Loading..
author
Loading..
TalTech department
Loading..
subject term
Loading..
series
Loading..
name of the person
Loading..
keyword
Loading..
Clear
Number of records
7
Look more..
(4/792)
Export
export all inquiry results
(7)
Save TXT fail
print
Open for editing with marked entries
my bookmarks
display
Bibliographic view
Short view
sort
author ascending
author descending
year of publication ascending
year of publication descending
title ascending
title descending
1
book article EST
/
book article ENG
Active power electronic transformer based on modular building blocks
Roasto, Indrek
;
Romero-Cadaval, Enrique
;
Martins, Joao
Proceedings : IECON 2013 - 39th Annual Conference of the IEEE Industrial Electronics Society : Austria Center Vienna, Vienna, Austria, 10-14 November, 2013
2013
/
p. 5922-5927 : ill
https://doi.org/10.1109/IECON.2013.6700106
Conference Proceedings at Scopus
Article at Scopus
book article EST
/
book article ENG
2
book article
Optimal reactive power control in a multi-machine thermal power plant
Trummal, Tarmo
;
Andreesen, Guido
;
Kilter, Jako
2020 21st International Scientific Conference on Electric Power Engineering (EPE), October 19-21, 2020, Prague, Czech Republic
2020
https://doi.org/10.1109/EPE51172.2020.9269239
book article
3
book article
Reactive power control for bidirectional isolated high-frequency link converter
Emiliani, Pietro
;
Blinov, Andrei
;
Peftitsis, Dimosthenis
;
Giannakis, Andreas
;
Vinnikov, Dmitri
2022 International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM)
2022
/
p. 372-376
https://doi.org/10.1109/SPEEDAM53979.2022.9842131
book article
4
book article
Single-phase power electronics transformer with active functions for smart grid
Minambres-Marcos, Victor
;
Roasto, Indrek
;
Romero-Cadaval, Enrique
;
Strzelecki, Ryszard
;
Barrero-Gonzalez, Fermin
2015 9th International Conference on Compatibility and Power Electronics (CPE) : proceedings : Faculty of Science and Technology (FCT), Caparica, Lisbon, Portugal, 24-26 June, 2015
2015
/
p. 528-533 : ill
http://dx.doi.org/10.1109/CPE.2015.7231131
book article
5
book article
The potential of distribution grid as an alternative source for reactive power control in transmission grid
Astapov, Victor
;
Divshali, Poria
;
Söder, Lennart
2018 19th International Scientific Conference on Electric Power Engineering (EPE 2018) : Brno, Czech Republic, 16-18 May, 2018
2018
/
p. 64–69 : ill
https://doi.org/10.1109/EPE.2018.8396031
book article
6
journal article
Utilizing demand response in load modelling for voltage and reactive power control studies
Drovtar, Imre
;
Leinakse, Madis
;
Tuttelberg, Kaur
;
Kilter, Jako
IEEE transactions on power systems
2024
/
12 p
https://doi.org/10.1109/TPWRS.2024.3425157
journal article
7
book article
Voltage and reactive power control in islanded microgrids without communication link
Armstorfer, Andreas
;
Biechl, Helmuth
;
Rosin, Argo
2020 17th Biennial Baltic electronics conference, Tallinn, Estonia, October 6-8, 2020 : proceedings
2020
/
6 p. : ill
https://doi.org/10.1109/BEC49624.2020.9277219
book article
Related publications
1
Mathematical modeling and control strategies for islanded microgrids = Saartalitluses mikrovõrkude matemaatiline modelleerimine ja juhtimisstrateegiad
Number of records 7, displaying
1 - 7
keyword
789
1.
reactive power control
2.
leakage current and reactive power supporting
3.
reactive power
4.
reactive power compensation
5.
reactive power injection
6.
reactive power management
7.
reactive power provision
8.
bidirectional power flow control
9.
electric power system control
10.
power based control
11.
power control
12.
power distribution control
13.
power system control
14.
topology/power control
15.
finite control set-model predictive control (FCS-MPC)
16.
modulated finite control set-model predictive control
17.
power electronics applications in power systems and utilities
18.
chiefly reactive CSR
19.
C-reactive protein
20.
functional reactive programming
21.
highly reactive viscoelastic liquids
22.
reactive annealing
23.
reactive atmosphere
24.
reactive dip-coating
25.
reactive energy
26.
reactive extrusion
27.
reactive laser powder-bed fusion
28.
reactive measures
29.
reactive melt blending
30.
reactive nitrogen
31.
reactive nitrogen budget
32.
reactive oxygen specie
33.
reactive oxygen species
34.
reactive oxygen species (ROS)
35.
reactive risk management
36.
reactive sintering
37.
reactive vacuum sintering
38.
access control
39.
acoustic noise control
40.
active thermal control
41.
adaptive control
42.
adaptive control systems
43.
adaptive droop control
44.
advanced control
45.
advanced dynamic control
46.
air traffic control
47.
aircraft control
48.
attitude determination and control
49.
automated control
50.
automatic control
51.
automatic control systems
52.
Automatic generation control
53.
automatic voltage control
54.
average current mode control
55.
BESS Control Strategy
56.
Bilateral output feedback control
57.
blood pressure control
58.
bottom-up control
59.
boundary control
60.
Building Automation and Control System (BACS)
61.
building automation and control systems
62.
case–control
63.
case-control studies
64.
centralized control
65.
centralized control system
66.
change of control
67.
chaos control
68.
chelation control
69.
climate control
70.
climate control in historic buildings
71.
closed loop control
72.
closed-loop control
73.
cognitive control
74.
command and control systems
75.
composite winding density control
76.
computer control
77.
concurrency control
78.
congestion control
79.
construction planning and control
80.
consultation command and control
81.
continuous control set
82.
control
83.
control algorithm
84.
Control allocation
85.
control and data path tests
86.
control and systems theory
87.
control applications
88.
control architecture
89.
control design
90.
control engineering computer applications
91.
control fault models
92.
control faults
93.
control function
94.
control interactions
95.
control manholes
96.
control methodology
97.
control methods
98.
control modes
99.
control nonlinearities
100.
control objectives
101.
control of multilevel converters
102.
control optimization
103.
control optimization strategies
104.
control part
105.
control problems
106.
control reconfiguration
107.
control strategy
108.
control system
109.
control system analysis
110.
control system design
111.
control system for grid integration
112.
control system stability
113.
control system synthesis
114.
control systems
115.
control systems commissioning
116.
control systems design
117.
control theory
118.
control valve characteristic
119.
converter control
120.
coordinated control
121.
cost-effective heating control
122.
crack control
123.
critical control points
124.
current control
125.
cycle skipping control
126.
data-driven control
127.
dc droop control
128.
DC -link control
129.
DC-link control
130.
dc-link voltage control
131.
deadbeat control
132.
decentralized model predictive control
133.
delay control systems
134.
delimited control operators
135.
detailed control modelling
136.
diffuse pollution control
137.
digital control
138.
digital control systems
139.
digital current mode control
140.
direct field-oriented control (DFOC)
141.
direct torque control
142.
direct torque control (DTC)
143.
discrete time control systems
144.
distributed average integral control
145.
distributed control
146.
disturbance rejection control
147.
droop control
148.
droop control bandwidth
149.
droop current control
150.
droplet generation rate control
151.
droplet size control
152.
duty cycle control
153.
dynamic control
154.
efficient control strategy
155.
electric control equipment
156.
electric machine control
157.
electric variables control
158.
embedded control
159.
emission control
160.
emission control area (ECA)
161.
emission control areas
162.
encoderless control
163.
energy control
164.
energy control unit (ECU)
165.
equiaxed grain control
166.
equivalent control
167.
EU merger control
168.
eutrophication control
169.
event-based control
170.
event-triggered control
171.
export control
172.
fault tolerant control
173.
fault-tolerant control
174.
feedback control
175.
feeder-side control
176.
feedforward control
177.
field-oriented control
178.
finite cycle-based model predictive control
179.
fire control by climate
180.
flag state control
181.
flatness-based control
182.
flight control
183.
flow rate control
184.
fluid flow control
185.
fluid flow control
186.
flux control
187.
FOPID retuning control
188.
force control
189.
fractional control
190.
fractional control implementation
191.
fractional PID control
192.
fractional-order pid control
193.
fractional-order sliding mode control
194.
free predictive control
195.
frequency control
196.
frequency deviation control
197.
fuzzy control
198.
fuzzy logic control
199.
Gain control
200.
general control modulo of the oscillatory behavior
201.
geometric control
202.
grid-forming control
203.
Health locus-of-control
204.
hierarchical control
205.
high-level control fault model
206.
high-level control faults
207.
HVAC control strategies
208.
hydraulic control
209.
hysteresis current control
210.
industrial control
211.
industrial control system (ICS)
212.
industrial control systems
213.
Industrial Control Systems (ICS)
214.
Infection control
215.
information control
216.
information flow control
217.
intelligent control
218.
intelligent lighting control
219.
interfacing and control of renewable
220.
interleaved control
221.
internal control
222.
inventory control
223.
iterative modelling and control design
224.
judicial control
225.
level control
226.
lighting control
227.
linear control system
228.
load control
229.
load frequency control
230.
load frequency control (LFC)
231.
locomotion control
232.
locus of control
233.
low-level control system transportation
234.
LQG control
235.
LQR control
236.
machine control
237.
machine vector control
238.
management control systems
239.
master-slave control
240.
maximum boost control
241.
mechatronics system control
242.
Media Access Control (MAC)
243.
medium access control
244.
medium access control (MAC)
245.
merger control
246.
metabolic control analysis
247.
minimax control
248.
model predictive control
249.
model predictive control (MPC)
250.
model reference adaptive control
251.
model-based control
252.
model-free control
253.
modeling for control
254.
moisture control
255.
monlinear control systems
256.
motion control
257.
motor control
258.
multi-loop model reference control
259.
multimode control
260.
multi-mode control
261.
multi-rate control
262.
multi-resonant control
263.
multivariable control
264.
multivariable control systems
265.
Networked control systems
266.
networked control systems (NCSs)
267.
neural fuzzy modelling control
268.
noise control
269.
nonlinear control
270.
nonlinear control strategy
271.
nonlinear control system
272.
nonlinear control systems
273.
nonlinear model predictive control
274.
open loop control
275.
optimal control
276.
optimal control systems
277.
output control
278.
output feedback control
279.
partial control of emergent behavior
280.
passive flow control
281.
passive solar control
282.
passivity based control
283.
passivity-based control (PBC)
284.
PD control
285.
peak current mode control
286.
perceived behavioral control
287.
pest control
288.
phase control
289.
physical control channels
290.
PI control
291.
PI control parameters
292.
pid control
293.
piecewise linear droop control
294.
planning and control
295.
PlcOpen motion control function blocks
296.
pollution control
297.
port state control
298.
PR control
299.
predictive control
300.
predictive torque control
301.
pressure control
302.
pressure control valve
303.
pre-symptomatic period risk control
304.
prevention and control
305.
price based control
306.
price based control of industrial processes
307.
primary droop control
308.
process control
309.
production control
310.
programmable control
311.
proportional control systems
312.
proportional–integral–derivative (PID) control
313.
pulse control
314.
PWM control
315.
quality assurance and control
316.
quality control
317.
quality control plan
318.
randomized control trial
319.
rapid control prototyping
320.
real time control
321.
remote control
322.
renewable sources control
323.
resonant control
324.
retuning control
325.
ripple-based control
326.
robot control
327.
robotic control
328.
robust control
329.
rule-based control
330.
SECA "Sulphur Emission Control Area"
331.
SECA (sulphur emission control areas) regulations
332.
secondary control
333.
segmented control
334.
sense of control
335.
sensorless control
336.
shading control principles
337.
shootthrough control methods
338.
shoot-through control methods
339.
SISO control
340.
sliding mode control
341.
sliding model control
342.
slip control
343.
smart control
344.
sole control
345.
sound volume control
346.
stabilizing control
347.
state-feedback control
348.
stochastic control
349.
stormwater inlet control
350.
supervisory control and data acquisition (SCADA)
351.
switching control method
352.
synthetic control method
353.
Synthetic inertia control (SIC)
354.
temperature control
355.
thermal variables control
356.
three term control systems
357.
topographic control
358.
topology morphing control
359.
topology morphing control (TMC)
360.
torque control
361.
towing carriage control
362.
tracking control
363.
traffic control
364.
traffic signal control
365.
trajectory control
366.
transmission control protocol
367.
triple-loop control
368.
two term control systems
369.
two-term control
370.
UAV formation control
371.
ultralocal model (ULM) control
372.
unfolding-control
373.
uplink control channel design
374.
vector control
375.
version control
376.
vibration control
377.
Wide-Area control
378.
wind turbine control
379.
winding process control
380.
wireless networked control systems
381.
virtual inertia control
382.
volt/VAR control
383.
voltage control
384.
voltage mode control
385.
voltage-oriented control (VOC)
386.
work locus of control
387.
AC power converters
388.
AC/DC power converter
389.
ac/dc-dc power converters
390.
AC‐AC power convertors
391.
ac-dc power conversion
392.
AC-DC power converter
393.
AC-DC power converters
394.
active power
395.
active power decoupling
396.
adaptive power allocation
397.
aircraft electric power system
398.
alpha power variability
399.
auxiliary power supply
400.
balance of power
401.
balancing power
402.
bidirectional power flow
403.
bidirectional power transfer
404.
bisection based optimal power allocation
405.
boost power converter
406.
buck-boost full power converter
407.
buck–boost power converter
408.
capabilities of power electronics
409.
capacitive power transfer
410.
CHP (combined power and heat)
411.
combined heat and power
412.
combined heat and power economic dispatch (CHPED)
413.
combined heat and power plant
414.
common-ground power converter
415.
concentrated solar power
416.
condensing power plant
417.
connection power
418.
constant power load
419.
constant power source
420.
consumed power minimization
421.
consumer power system
422.
consumer-perceived power
423.
contribution to power quality deterioration
424.
conventional power plant
425.
cyber physical power system (CPPS)
426.
cyber power Europe
427.
DC power supply
428.
DC/DC power conversion
429.
DC/DC power converters
430.
DC-AC power conversion
431.
DC-AC power converters
432.
DC-AC power convertors
433.
DC-DC power conversion
434.
DC‐DC power conversion
435.
DC-DC power converter
436.
DC-DC power converters
437.
DC–DC power converters
438.
DC-DC power convertors
439.
DC‐DC power convertors
440.
Differential Power Analysis (DPA)
441.
differential power processing (DPP)
442.
dimensioning cooling power
443.
directional power spectral density
444.
Discrete power device
445.
distributed power
446.
distributed power generation
447.
distributed power systems
448.
distrubuted power generation
449.
double power-law
450.
dual-purpose dc-dc/ac power converter
451.
economic power dispatch
452.
Egyptian power system
453.
electric power distribution
454.
electric power generation
455.
electric power storage system
456.
electric power system stability
457.
electric power systems
458.
electric power transmission
459.
electric power transmission networks
460.
electric power utilization
461.
electrical power domain
462.
electrical power quality
463.
electrical power systems
464.
emerging power converters
465.
faults in power system
466.
flexibility in power systems
467.
fluid power feeding system with a pneumo-hydraulic accumulator
468.
fluid power system
469.
fossil fuel power plants
470.
fractional power zero-pole
471.
fuel cell power systems
472.
full power converter
473.
full power Z -source converter
474.
functional power plants
475.
functional power-plants
476.
GaAs power devices
477.
galvanically isolated DC-DC power converter
478.
Geological Power Bank
479.
global maximum power point
480.
global power sharing
481.
grid-connected power supply
482.
grid-forming power converters
483.
heat and power plant
484.
heating power
485.
high percentage of wind power
486.
high power density
487.
high step-up power converter
488.
high voltage power converters
489.
hybrid power system
490.
hydraulic power
491.
hydroelectric power generation
492.
hydroelectric power station (HEPS)
493.
inductive power transfer
494.
inductive power transfer (IPT)
495.
inductive power transmission
496.
inductive wireless power transfer link
497.
industrial power systems
498.
instantaneous power balancing
499.
integration of solar power plants
500.
Interconnected power system
501.
isolated power conditioning unit (PCU)
502.
isolated power converters
503.
Kalman-filter based maximum power point tracking (KF-MPPT)
504.
limited power
505.
lithium batteries and power system modeling
506.
local power supply system
507.
low power
508.
low-power ASIC design
509.
low-power decoupling
510.
low-power designs
511.
low-power device
512.
market power
513.
market power mitigation
514.
maximum available power
515.
maximum power point
516.
maximum power point tracker
517.
Maximum power point trackers
518.
maximum power point tracking
519.
maximum power point tracking (MPPT)
520.
medium voltage power cables
521.
Mini-block power plant
522.
Modern power system
523.
module level power electronics (MLPE)
524.
module-level power electronics (MLPE)
525.
multi-machine industrial power plant
526.
multi-machine power system
527.
narrowband power line communications
528.
non-active power
529.
non-coercive power
530.
normative power
531.
nuclear power
532.
off-grid hybrid power supply
533.
Off-shore wind power
534.
offshore wind power plants
535.
oil shale-fired power plants
536.
oil-shale power generation
537.
parallel active power filter
538.
partial power based on buck-boost resonance converter
539.
partial power based on isolated Z - Source converter(PPZSC)
540.
partial power conversion
541.
partial power converter
542.
partial power converter (PPC)
543.
partial power converters
544.
partial power converters (PPC)
545.
partial power DC-DC converter
546.
partial power processing
547.
Partial power processing (PPP)
548.
peak power limiting
549.
photovoltaic power plant
550.
photovoltaic power systems
551.
power
552.
power allocation
553.
power amplifier
554.
Power amplifiers
555.
power aware computing
556.
power balance
557.
power bed fusion
558.
power cable
559.
Power cables
560.
power capacitors
561.
power chart
562.
power combiner
563.
power conditioner
564.
power conditioning
565.
power conditioning units (PCUs)
566.
power consensus
567.
power consumption
568.
power consumption of production
569.
power conversion
570.
power converter
571.
power converter interfaces
572.
power converters
573.
power converters design
574.
power converters for EV
575.
power decoupling
576.
Power Delay Product (PDP)
577.
power delivery network
578.
power demand
579.
power density
580.
power devices
581.
power diodes
582.
power dissipation
583.
power disspation
584.
power distribution
585.
power distribution faults
586.
power distribution lines
587.
power distribution network
588.
power distribution system
589.
power electronic building block
590.
power electronic converter
591.
power electronic converters
592.
power electronic interfaces
593.
power electronic interfaces for renewable energy sources
594.
power electronic transformer
595.
power electronics
596.
power electronics (PE)
597.
power electronics converter
598.
power electronics converters
599.
power electronics solutions
600.
power engineering
601.
power engineering computing
602.
power exchange
603.
power factor
604.
power factor correction
605.
power factor correction (PFC)
606.
power flow
607.
power flow equations
608.
power forecasting
609.
power frequency
610.
power generation
611.
power generation dispatch
612.
power generation economics
613.
power generation planning
614.
power grid
615.
power grid imbalance
616.
power grid project
617.
power grids
618.
power harmonic filters
619.
power imbalance
620.
Power industry
621.
power injection
622.
power inverter
623.
power inverters
624.
Power Iteration Clustering (PIC)
625.
power law
626.
Power leveling strategy
627.
power limitation
628.
power line communication
629.
power line construction
630.
power loss
631.
power loss minimization
632.
power loss model
633.
power losses
634.
power management
635.
power market model
636.
power markets
637.
power measurement
638.
power mismatch analysis
639.
power module
640.
power MOSFET
641.
power of discrimination
642.
power optimization
643.
power optimizer
644.
Power oscillation damping controller (PODC)
645.
power outage
646.
Power Plant
647.
power plant cycling
648.
power plant pollution
649.
Power plants
650.
power quality
651.
Power quality (PQ)
652.
power quality benchmarking
653.
power quality case study
654.
Power Quality Disturbances (PQD)
655.
power quality disturbances (PQDs)
656.
power quality legislation
657.
power quality measurement
658.
power quality measurement equipment
659.
power quality measurements
660.
power quality monitoring
661.
power quality parameters
662.
power reduction
663.
power reliability
664.
power semiconductor device
665.
power semiconductor devices
666.
power semiconductor switches
667.
power series
668.
power sharing
669.
power signature
670.
power smoothing
671.
power sources
672.
power spectral density
673.
power spectrum
674.
Power storage
675.
power supplier
676.
power supplies
677.
power supplies to apparatus
678.
power supply
679.
power swings
680.
power system
681.
power system analysis computing
682.
power system dynamics
683.
power system economics
684.
power system faults
685.
power system harmonics
686.
power system management
687.
power system measurements
688.
power system modeling
689.
power system modelling
690.
power system operation
691.
power system parameter estimation
692.
power system planning
693.
power system protection
694.
power system reliability
695.
power system resilience
696.
power system restoration
697.
power system security
698.
power system simulation
699.
power system simulations
700.
Power system stabilizer (PSS)
701.
power system stability
702.
power system transient stability
703.
power systems
704.
Power systems expansion
705.
power systems flexibility
706.
power sytems
707.
power to hydrogen technology
708.
power transfer distribution factor
709.
power transformers
710.
power transistors
711.
power transmission
712.
power transmission lines
713.
power variations
714.
power verification
715.
power-aware
716.
power-electronic converters
717.
power-factor correction
718.
power-flow equations
719.
power-hardware-in-the-loop
720.
power-laws
721.
power-sharing
722.
power-to-gas based storage system
723.
Power-to-heat
724.
power-to-hydrogen
725.
power-to-X
726.
PQ (Power Quality)
727.
PQM (Power Quality Monitoring)
728.
pulse width modulated power converters
729.
pulsed power load (PPL)
730.
pulsewidth-modulated power converters
731.
PV module level power electronics
732.
PV power generation
733.
PV power output
734.
PV power plant
735.
relative band power
736.
relative gamma power
737.
resonant power convertors
738.
reverse power flow
739.
reverse power transfer
740.
r-th power residue symbol
741.
series partial power converter (S-PPC)
742.
series partial power converter (S-PPC) based on the push-pull
743.
shade-tolerant maximum power point tracking (MPPT)
744.
shale oil and power cogeneration
745.
shunt active power filter
746.
smart power electronics
747.
smart power grids
748.
Soft power
749.
solar power
750.
solar power forecasting
751.
solar power generation
752.
solar power plant integration
753.
space-based solar power
754.
static power converters
755.
surplus power factor
756.
sustainable power engineering
757.
switch mode power supply
758.
switched mode power supplies
759.
switched-mode power supplies
760.
switchedmode power supply
761.
switched-mode power supply
762.
symbolic power
763.
talkative power conversion
764.
thermal power plant
765.
thermal power plants
766.
Thermal Power Station
767.
theta band power
768.
three-phase power factor correction (PFC) converter
769.
time-delay renewable power systems
770.
topological power plant
771.
Unified power flow controller (UPFC)
772.
uninterruptible power supply (UPS)
773.
wave power
774.
welding power supply
775.
wind power
776.
wind power forecasting
777.
wind power generation
778.
wind power generators
779.
wind power plants
780.
wind power production
781.
Wind-photovoltaic-thermal-bundled power
782.
wireless power transfer
783.
virtual power plant
784.
virtual power plant (VPP)
785.
virtual power plants
786.
virtual power plant's (VPPs)
787.
working power of luminaires
788.
voting power
789.
15min power balance
TalTech department
1
1.
Department of Electrical Power Engineering and Mechatronics
subject term
1
1.
Enefit Power
author
1
1.
Power, Ian M.
×
match
starts with
ends with
containes
sort
Relevance
ascending
descending
year of publication
author
TalTech department
subject term
series
name of the person
keyword
Otsing
Valikud
0
year of publication
AND
OR
NOT
author
AND
OR
NOT
TalTech department
AND
OR
NOT
subject term
AND
OR
NOT
series
AND
OR
NOT
name of the person
AND
OR
NOT
keyword
AND
OR
NOT