Research interests

“Science is the art of asking right questions instead of providing right answers.”

My greatest skill and advantage as a researcher is conceiving creative and original ideas to construct innovative science and engineering solutions with important societal impact and their applications which can be beneficial for people, environment and nature in general. As my ideas are often expanding beyond the scope of my formal educational background, I welcome curious collaborators with strong theoretical background from the particular fields.

I would hereby classify my research interests into five categories: (1) Hydrology, (2) Coastal and Ocean Engineering, (3) Biophysics (Biohydrodynamics), (4) Structural Mechanics (5) Psychology, (6) Co-authorship optimization and (7) Natural currents oscillations. Below are each of these research interests explained in more details, with references to my past contributions from the particular research interest.

(1) Hydrology

I am developing Early Warning Systems (EWS) for human evacuations as a result of flash floods from rivers and associated pollution transport in the coastal zones. It is challenging to develop such EWS because river-runoff modelling calculation is complicated because of a lot heterogeneous parameters which are occurring simultaneously in a river watershed, such as landuse, vegetation type, soil type, soil depth, soil vertical profile, porosity, slope, hydraulic conductivity and spatiotemporal distribution of rainfall, among others. In this context, my research goal is optimization of parameters of numerical models, in order to be able to represent above mentioned parameters as much as possible realistically by using data of historically recorded the most extreme floods (model calibration). When model parameters are calibrated on such way, then they can be used for real-time forecasting of river water levels and discharges using a meteorological real-time rainfall forecast as the river modeling input (model validation). On this way, floods can be predicted with high accuracy several hours of days. Quality of methodologies that I am developing can be evaluated in terms of lower or higher prediction accuracy of river water levels and discharges, and in this context I am constantly trying to propose original ideas and new methodologies which can be contributory to the current scientific knowledge.

Past contributions related to the research interest (1):

(A) Trošelj J. and Lee HS. Modelling Typhoon-Induced Extreme River Discharges: A Case Study of Typhoon Hagibis in Japan, Journal of Hydrology: Regional Studies 34: 100776, doi.org/10.1016/j.ejrh.2021.100776, 2021.

(B) Troselj J., Sayama T., Varlamov SM., Sasaki T., Racault M-F., Takara K., Miyazawa Y., Kuroki R., Yamagata T., Yamashiki Y. Modeling of extreme freshwater outflow from the north-eastern Japanese river basins to western Pacific Ocean, Journal of Hydrology, Vol. 555, pp. 956-970, doi.org/10.1016/j.jhydrol.2017.10.042, 2017. 

(C) Troselj J., Invited Lecture. Modeling of Extreme Freshwater Outflow from the North-Eastern Japanese River Basins to Western Pacific Ocean, 12th Scientific Colloquium of the University of Rijeka, Rijeka, Croatia, 22/12/2017.

(D) Troselj J., Ozanic, N. Influence of Planned Reservoir Zoretici to Possibilities of Using Water Resources of Rjecina River, Proceedings of University of Rijeka, Faculty of Civil Engineering, Vol. 15, pp. 59-83, 2013. 

(2) Coastal and Ocean engineering

I am conducting numerical modeling using ROMS model and downscaling it to very fine scales (200 m). Hindcasts of the downscaled fine resolution scale coastal dynamics are important to quantitatively analyze variations in storm surge heights, water temperature, salinity and high velocities which induce shoreline changes. This methodology can realistically represent ocean dynamics in coastal zones, where ocean dynamics is the most complex and the most challenging to be modeled due to the associated shallow water environment. This modeling approach is helpful in understanding and assessing shoreline changes and damages on the associated coastal aquaculture and applicable for climate change impact assessment, in which context it can ultimately serve as a guideline for developing adaptation policies.

Past contributions related to the research interest (2):

(A) Trošelj J., Ninomiya J., Takewaka S. and Mori N. Dynamical Downscaling of Coastal Dynamics for Two Extreme Storm Surge Events in Japan, Frontiers in Marine Science 7: 566277, doi.org/10.3389/fmars.2020.566277, 2021.

(B) Troselj J., Imai Y., Ninomiya J., Mori N. Seasonal Variabilities of Sea Surface Temperature and Salinity on Ibaraki Coast, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), Vol. 75, No. 2, pp. 1213-1218, doi.org/10.2208/kaigan.75.I_1213, 2019. 

(C) Troselj J., Imai Y., Ninomiya J., Mori N. Coastal Current Downscaling Emphasizing Freshwater Impact on Ibaraki Coast, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), Vol. 74, No. 2, pp. 1357-1362, doi.org/10.2208/kaigan.74.I_1357, 2018. 

(D) Troselj J., Imai Y., Ninomiya J., Mori N. Invited Talk. Downscaling of Coastal Current to 200 m Scale in the Ibaraki Prefecture with Included Freshwater Outflow Impact, Japan Geoscience Annual Meeting, Tokyo, Japan, 21/5/2018.

(E) Hamano, R., Ninomiya, J., Troselj J., Mori N. Analysis of Polar Front and Thermal Environment in the Sea of Japan using Long-Term Ocean Reanalysis Data, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), Vol. 75, No. 2, pp. 1201-1206, doi.org/10.2208/kaigan.75.I_1201, 2019. 

(F) Ninomiya J., Hamano R., Mori N., Troselj J., Ishikawa Y., Nishikawa S. Evaluation of Reproducebility and Water Flux Analyses at Straits of Japan Sea using Long-term Ocean Reanalysis Data, Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), Vol. 74, No. 2, pp. 988-993, doi.org/10.2208/jscejoe.74.I_988, 2018. 

(3) Biophysics (Biohydrodynamics)

I am looking for collaborators who would be interested to collaborate with me in developing a fundamentally new approach which can real-time forecast seasonal migration routes of sea animals, such as whales.  Furthermore, I am looking for collaborations who have high resolutions observed seasonal migration data of sea animals, for validation of the above mentioned fundamentally new approach. I think that this research topic is pretty much unexplored and uncertain by nowadays science. In other words, migration routes of whales are known because of existence of observed data, however there is no any methodology currently developed which can precisely forecast the migration routes as a function of oceanic currents, water density, swimming depth and similar associated parameters.

Past contributions related to the research interest (3):

This idea is still in development and not yet published. My new fundamental approach might eventually lead to proposing of a new physical non-dimensional number in future, which I call Navigability Number. Navigability Number describes environmental conditions for ease of sea animals’ movement through the water. The equation for Navigability Number can be expressed as complex combination of relative pressure (“static” component of Navigability Number) and relative inertia (“dynamic” component of Navigability Number). This equation can be independently derived on three different ways, using momentum-momentum, momentum-energy and energy-energy approaches. Navigability Number is approximately inversely proportional to the total drag.

Some preliminary plots of Navigability Number for Pacific Ocean for 1st of January, 2015 on depth 1.9 m in east-west direction (u-Navigability, upper plot) and north-south direction (v-Navigability, lower plot) are shown below. Yellow color indicates locations where swimming by sea animals in east/north directions is easy whereas blue color indicates locations where swimming in west/south directions is easy. I am going to test and validate such preliminary results with observed seasonal migration data of sea animals.

 

Additionally, below are listed some of scientific questions which might be possibly answered by using the Navigability Number:

1a. Which is the way (or formula) to determine long distance migration paths (Longitude/Latitude and depth) for whales? Which are the most important input parameters? Which-is-the-way-or-formula-to-determine-long-distance-migration-paths-longitude-latitude-and-depth-of-whales?

1b. If airplanes have the most optimal altitude for long distance flying, do submarines similarly have the most optimal depth for long distance diving?

1c. Which is the way (or formula) to determine the fastest (in terms of physical parameters) long distance diving path (Longitude/Latitude and depth) for submarines?Which are the most important input parameters? Which-is-the-way-to-determine-the-most-optimal-long-distance-diving-latitude-and-altitude-for-submarines?

1d. Which is the formula to determine the most optimal (the fastest while spending the least amount of fuel) long distance flying Longitude/Latitude and altitude for airplanes? Is input only the wind speed or other parameters are important as well? Which-is-the-formula-to-determine-the-most-optimal-long-distance-flying-latitude-and-altitude-for airplanes?

1e. Which is the way (or formula) to determine long distance migration paths (Longitude/Latitude and depth) for birds? Which are the most important input parameters? Which-is-the-way-or-formula-to-determine-long-distance-migration-paths-longitude-latitude-and-altitude-for-birds?

2. In 6 meters deep swimming pool, at which of these depths a professional diver can achieve the highest maximum horizontal diving velocity, at 1, 3, or 5 meters under water? https://www.researchgate.net/post/What_is_the_relation_between_dept_of_diving_and_horizontal_diving_speed?fbclid=IwAR0ThsOUyKnLQUn_whAxiIuKtT5AlQd_GB2jeeOHSVwicRY-MHeJW2gYPrk

3. Which is impact of fluid velocity direction to supercavitation, if fluid velocity direction is: A) the same as floating object; B) opposite than floating object; C) zero? Which-is-impact-of-fluid-velocity-direction-to-supercavitation?  https://en.wikipedia.org/wiki/Supercavitation

4a. Is electromagnetic buoyancy, in addition to gravitational buoyancy, also an important factor which should be taken into account in order to explain phenomena of long distance flying by airplanes and/or long distance diving by submarines? https://en.wikipedia.org/wiki/Electromagnetic_buoyancy

4b. Is electromagnetic buoyancy an important factor which should be taken into account in order to explain phenomena of long distance flying by spiders? https://en.wikipedia.org/wiki/Ballooning_(spider)

(4) Structural Mechanics

I taught Structural Mechanics as a Student’s tutor for several years and from that teaching experience I have developed an innovative and simple method which can quickly and easily determine geometric stability of structures. Therefore, my new method can precisely answer to this complex question, where the idea itself is explained in more detail: https://www.researchgate.net/post/How_to_Determine_Geometric_Stability_of_Complex_Structural_Frames

Note, the question above is the first offered solution when keywords ‘geometric stability frames’ are entered into the Google Search, because it was read by more than 2100 unique internet users in less than 3 years, thus adding to my assumption that this question is unanswered or unclearly answered in nowadays science.

Past contributions related to the research interest (4):

(A) I participated among the 15 qualified finalists in the science contest Falling Walls Lab Tokyo 2018: https://euraxess.ec.europa.eu/worldwide/japan/science-communication-events/falling-walls-lab-tokyo/falling-walls-lab-tokyo-2018

I did not yet publish this method because I want to develop and polish it further in order to be applicable not only to frames but also to trusses and in principle to every structure in general. I am looking for collaborators who can explain if these structural systems (open-loop frames, closed-loop frames and trusses) drawn below are stable or unstable using currently known methods and who are willing to collaborate with me in advisory role in publishing the new determination method.

(5) Psychology

I think that visions and hallucinations are greatly misunderstood phenomena in nowadays medical science and psychology because of a very thin line which separates these phenomena from each other. This is because visions should not be classified as a mental disorder, but hallucinations should definitely be classified as a mental disorder.

Past contributions related to the research interest (5):

I have not published past contributions on this topic yet. However, my contribution to better understanding of visions and hallucinations will be a new research paper, which I am currently writing as a co-author with a student. The working title of the paper is: “Visions are like dreams, but hallucinations are like nightmares”. The working hypothesis of the paper is as follows. Current literature states: “There are not existing hallucinations without psychosis.” However, the objective of our study is to introduce this new hypothesis: “Visions are hallucinations without psychosis”. As both the student and me do not have any medical background, we welcome collaborators who have medical background relevant to this topic.

(6) Co-authorship optimization

My hypothesis: The most optimal ratio of co-authorship responsibilities for the published contents among main author and all co-authors together is 23:77%.

Academics who support this hypothesis are the ones who thinks that science is team work. 

(7) Natural currents oscillations

My hypothesis: Wind and ocean currents should be deterministically defined as damping harmonic oscillators.

Academics who support this hypothesis agree with quotes which was already envisioned by Albert Einstein and Nikola Tesla.

Albert: “Everything in Life is Vibration

Tesla: “If you wish to understand the Universe think of energy, frequency and vibration.“

I search for collaborators on publishing hypothesis. 

“Science is the art of asking right questions instead of providing right answers.”

My greatest skill and advantage as a researcher is conceiving creative and original ideas to construct innovative science and engineering solutions with important societal impact and their applications which can be beneficial for people, environment and nature in general. As my ideas are often expanding beyond the scope of my formal educational background, I welcome curious collaborators with strong theoretical background from the particular fields.

I would hereby classify my research interests into five categories: (1) Hydrology, (2) Coastal and Ocean Engineering, (3) Biophysics (Biohydrodynamics), (4) Structural Mechanics (5) Psychology, (6) Co-authorship optimization and (7) Natural currents oscillations. Below are each of these research interests explained in more details, with references to my past contributions from the particular research interest.

(1) Hydrology

I am developing Early Warning Systems (EWS) for human evacuations as a result of flash floods from rivers and associated pollution transport in the coastal zones. It is challenging to develop such EWS because river-runoff modelling calculation is complicated because of a lot heterogeneous parameters which are occurring simultaneously in a river watershed, such as landuse, vegetation type, soil type, soil depth, soil vertical profile, porosity, slope, hydraulic conductivity and spatiotemporal distribution of rainfall, among others. In this context, my research goal is optimization of parameters of numerical models, in order to be able to represent above mentioned parameters as much as possible realistically by using data of historically recorded the most extreme floods (model calibration). When model parameters are calibrated on such way, then they can be used for real-time forecasting of river water levels and discharges using a meteorological real-time rainfall forecast as the river modeling input (model validation). On this way, floods can be predicted with high accuracy several hours of days. Quality of methodologies that I am developing can be evaluated in terms of lower or higher prediction accuracy of river water levels and discharges, and in this context I am constantly trying to propose original ideas and new methodologies which can be contributory to the current scientific knowledge.

Past contributions related to the research interest (1):

(A) Trošelj J. and Lee HS. Modelling Typhoon-Induced Extreme River Discharges: A Case Study of Typhoon Hagibis in Japan, Journal of Hydrology: Regional Studies 34: 100776, doi.org/10.1016/j.ejrh.2021.100776, 2021.

(B) Troselj J., Sayama T., Varlamov SM., Sasaki T., Racault M-F., Takara K., Miyazawa Y., Kuroki R., Yamagata T., Yamashiki Y. Modeling of extreme freshwater outflow from the north-eastern Japanese river basins to western Pacific Ocean, Journal of Hydrology, Vol. 555, pp. 956-970, doi.org/10.1016/j.jhydrol.2017.10.042, 2017. 

(C) Troselj J., Invited Lecture. Modeling of Extreme Freshwater Outflow from the North-Eastern Japanese River Basins to Western Pacific Ocean, 12th Scientific Colloquium of the University of Rijeka, Rijeka, Croatia, 22/12/2017.

(D) Troselj J., Ozanic, N. Influence of Planned Reservoir Zoretici to Possibilities of Using Water Resources of Rjecina River, Proceedings of University of Rijeka, Faculty of Civil Engineering, Vol. 15, pp. 59-83, 2013. 

(2) Coastal and Ocean engineering

I am conducting numerical modeling using ROMS model and downscaling it to very fine scales (200 m). Hindcasts of the downscaled fine resolution scale coastal dynamics are important to quantitatively analyze variations in storm surge heights, water temperature, salinity and high velocities which induce shoreline changes. This methodology can realistically represent ocean dynamics in coastal zones, where ocean dynamics is the most complex and the most challenging to be modeled due to the associated shallow water environment. This modeling approach is helpful in understanding and assessing shoreline changes and damages on the associated coastal aquaculture and applicable for climate change impact assessment, in which context it can ultimately serve as a guideline for developing adaptation policies.

Past contributions related to the research interest (2):

(A) Trošelj J., Ninomiya J., Takewaka S. and Mori N. Dynamical Downscaling of Coastal Dynamics for Two Extreme Storm Surge Events in Japan, Frontiers in Marine Science 7: 566277, doi.org/10.3389/fmars.2020.566277, 2021.

(B) Troselj J., Imai Y., Ninomiya J., Mori N. Seasonal Variabilities of Sea Surface Temperature and Salinity on Ibaraki Coast, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), Vol. 75, No. 2, pp. 1213-1218, doi.org/10.2208/kaigan.75.I_1213, 2019. 

(C) Troselj J., Imai Y., Ninomiya J., Mori N. Coastal Current Downscaling Emphasizing Freshwater Impact on Ibaraki Coast, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), Vol. 74, No. 2, pp. 1357-1362, doi.org/10.2208/kaigan.74.I_1357, 2018. 

(D) Troselj J., Imai Y., Ninomiya J., Mori N. Invited Talk. Downscaling of Coastal Current to 200 m Scale in the Ibaraki Prefecture with Included Freshwater Outflow Impact, Japan Geoscience Annual Meeting, Tokyo, Japan, 21/5/2018.

(E) Hamano, R., Ninomiya, J., Troselj J., Mori N. Analysis of Polar Front and Thermal Environment in the Sea of Japan using Long-Term Ocean Reanalysis Data, Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering), Vol. 75, No. 2, pp. 1201-1206, doi.org/10.2208/kaigan.75.I_1201, 2019. 

(F) Ninomiya J., Hamano R., Mori N., Troselj J., Ishikawa Y., Nishikawa S. Evaluation of Reproducebility and Water Flux Analyses at Straits of Japan Sea using Long-term Ocean Reanalysis Data, Journal of Japan Society of Civil Engineers, Ser. B3 (Ocean Engineering), Vol. 74, No. 2, pp. 988-993, doi.org/10.2208/jscejoe.74.I_988, 2018. 

(3) Biophysics (Biohydrodynamics)

I am looking for collaborators who would be interested to collaborate with me in developing a fundamentally new approach which can real-time forecast seasonal migration routes of sea animals, such as whales.  Furthermore, I am looking for collaborations who have high resolutions observed seasonal migration data of sea animals, for validation of the above mentioned fundamentally new approach. I think that this research topic is pretty much unexplored and uncertain by nowadays science. In other words, migration routes of whales are known because of existence of observed data, however there is no any methodology currently developed which can precisely forecast the migration routes as a function of oceanic currents, water density, swimming depth and similar associated parameters.

Past contributions related to the research interest (3):

This idea is still in development and not yet published. My new fundamental approach might eventually lead to proposing of a new physical non-dimensional number in future, which I call Navigability Number. Navigability Number describes environmental conditions for ease of sea animals’ movement through the water. The equation for Navigability Number can be expressed as complex combination of relative pressure (“static” component of Navigability Number) and relative inertia (“dynamic” component of Navigability Number). This equation can be independently derived on three different ways, using momentum-momentum, momentum-energy and energy-energy approaches. Navigability Number is approximately inversely proportional to the total drag.

Some preliminary plots of Navigability Number for Pacific Ocean for 1st of January, 2015 on depth 1.9 m in east-west direction (u-Navigability, upper plot) and north-south direction (v-Navigability, lower plot) are shown below. Yellow color indicates locations where swimming by sea animals in east/north directions is easy whereas blue color indicates locations where swimming in west/south directions is easy. I am going to test and validate such preliminary results with observed seasonal migration data of sea animals.

 

Additionally, below are listed some of scientific questions which might be possibly answered by using the Navigability Number:

1a. Which is the way (or formula) to determine long distance migration paths (Longitude/Latitude and depth) for whales? Which are the most important input parameters? Which-is-the-way-or-formula-to-determine-long-distance-migration-paths-longitude-latitude-and-depth-of-whales?

1b. If airplanes have the most optimal altitude for long distance flying, do submarines similarly have the most optimal depth for long distance diving?

1c. Which is the way (or formula) to determine the fastest (in terms of physical parameters) long distance diving path (Longitude/Latitude and depth) for submarines?Which are the most important input parameters? Which-is-the-way-to-determine-the-most-optimal-long-distance-diving-latitude-and-altitude-for-submarines?

1d. Which is the formula to determine the most optimal (the fastest while spending the least amount of fuel) long distance flying Longitude/Latitude and altitude for airplanes? Is input only the wind speed or other parameters are important as well? Which-is-the-formula-to-determine-the-most-optimal-long-distance-flying-latitude-and-altitude-for airplanes?

1e. Which is the way (or formula) to determine long distance migration paths (Longitude/Latitude and depth) for birds? Which are the most important input parameters? Which-is-the-way-or-formula-to-determine-long-distance-migration-paths-longitude-latitude-and-altitude-for-birds?

2. In 6 meters deep swimming pool, at which of these depths a professional diver can achieve the highest maximum horizontal diving velocity, at 1, 3, or 5 meters under water? https://www.researchgate.net/post/What_is_the_relation_between_dept_of_diving_and_horizontal_diving_speed?fbclid=IwAR0ThsOUyKnLQUn_whAxiIuKtT5AlQd_GB2jeeOHSVwicRY-MHeJW2gYPrk

3. Which is impact of fluid velocity direction to supercavitation, if fluid velocity direction is: A) the same as floating object; B) opposite than floating object; C) zero? Which-is-impact-of-fluid-velocity-direction-to-supercavitation?  https://en.wikipedia.org/wiki/Supercavitation

4a. Is electromagnetic buoyancy, in addition to gravitational buoyancy, also an important factor which should be taken into account in order to explain phenomena of long distance flying by airplanes and/or long distance diving by submarines? https://en.wikipedia.org/wiki/Electromagnetic_buoyancy

4b. Is electromagnetic buoyancy an important factor which should be taken into account in order to explain phenomena of long distance flying by spiders? https://en.wikipedia.org/wiki/Ballooning_(spider)

(4) Structural Mechanics

I taught Structural Mechanics as a Student’s tutor for several years and from that teaching experience I have developed an innovative and simple method which can quickly and easily determine geometric stability of structures. Therefore, my new method can precisely answer to this complex question, where the idea itself is explained in more detail: https://www.researchgate.net/post/How_to_Determine_Geometric_Stability_of_Complex_Structural_Frames

Note, the question above is the first offered solution when keywords ‘geometric stability frames’ are entered into the Google Search, because it was read by more than 2100 unique internet users in less than 3 years, thus adding to my assumption that this question is unanswered or unclearly answered in nowadays science.

Past contributions related to the research interest (4):

(A) I participated among the 15 qualified finalists in the science contest Falling Walls Lab Tokyo 2018: https://euraxess.ec.europa.eu/worldwide/japan/science-communication-events/falling-walls-lab-tokyo/falling-walls-lab-tokyo-2018

I did not yet publish this method because I want to develop and polish it further in order to be applicable not only to frames but also to trusses and in principle to every structure in general. I am looking for collaborators who can explain if these structural systems (open-loop frames, closed-loop frames and trusses) drawn below are stable or unstable using currently known methods and who are willing to collaborate with me in advisory role in publishing the new determination method.

(5) Psychology

I think that visions and hallucinations are greatly misunderstood phenomena in nowadays medical science and psychology because of a very thin line which separates these phenomena from each other. This is because visions should not be classified as a mental disorder, but hallucinations should definitely be classified as a mental disorder.

Past contributions related to the research interest (5):

I have not published past contributions on this topic yet. However, my contribution to better understanding of visions and hallucinations will be a new research paper, which I am currently writing as a co-author with a student. The working title of the paper is: “Visions are like dreams, but hallucinations are like nightmares”. The working hypothesis of the paper is as follows. Current literature states: “There are not existing hallucinations without psychosis.” However, the objective of our study is to introduce this new hypothesis: “Visions are hallucinations without psychosis”. As both the student and me do not have any medical background, we welcome collaborators who have medical background relevant to this topic.

(6) Co-authorship optimization

My hypothesis: The most optimal ratio of co-authorship responsibilities for the published contents among main author and all co-authors together is 23:77%.

Academics who support this hypothesis are the ones who thinks that science is team work. 

(7) Natural currents oscillations

My hypothesis: Wind and ocean currents should be deterministically defined as damping harmonic oscillators.

Academics who support this hypothesis agree with quotes which was already envisioned by Albert Einstein and Nikola Tesla.

Albert: “Everything in Life is Vibration

Tesla: “If you wish to understand the Universe think of energy, frequency and vibration.“